PESTICIDE MONITORING IN THE IRRIGATION AREAS OF SOUTH

PESTICIDE MONITORING IN THE IRRIGATIONAREAS OF SOUTH-WESTERN NSW

1990 - 1995

K H Bowmer, W Korth, A Scott, G McCorkelle, M Thomas

Technical Report 17/98; April 1998

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PESTICIDE MONITORING IN THE IRRIGATIONAREAS OF SOUTH-WESTERN NSW,

1990 - 1995

K H Bowmer, W Korth, A Scott, G McCorkelle, M Thomas

CSIRO LAND & WATER

April 1998

TECHNICAL REPORT 17/98

Acknowledgments

The authors gratefully acknowledge Gillian Napier of the CSIRO, and the technical officers ofthe NSW Department of Land & Water Conservation, NSW EPA, Murrumbidgee Irrigation,NSW Agriculture and NSW Department of Health who provided valuable information andadvice.

Funding of pesticide research from 1990-1995 at the CSIRO laboratories in Griffith, NSWwas provided by CSIRO Division of Water Resources, Land & Water Resources ResearchDevelopment Corporation, Murray-Darling Basin Commission, NSW Department of Land &Water Conservation, and the NSW Environment Protection Authority.

Cover photo; vegetable crop in the Murrumbidgee Irrigation Area being sprayed withinsecticide. (Bill van Aken, CSIRO)

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TABLE OF CONTENTS

Executive Summary 41. Introduction 102. Irrigation areas of south-western NSW 11

2.1 Location and size of irrigation areas and districts 112.2 Types of irrigated crops grown 142.3 Supply of water to irrigation farms 142.4 Disposal of drainage water from irrigation farms 15

3. Pesticide use in the irrigation areas of south-western NSW 163.1 Records of pesticide use patterns 163.2 Pesticide use on a crop by crop basis 163.3 Summary of pesticides most commonly used 193.4 Adjuvants 203.5 Aquatic weed control 213.6 Methods of pesticide application 213.7 Other biologically active chemicals, and pesticides used in the past 21

4. Fate and biological impact of pesticides 234.1 Physical pathways for pesticide transport 234.2 Partitioning of pesticides to soil or water 254.3 Persistence in the environment 264.4 Pesticide toxicity 264.5 Bioaccumulation of pesticides 274.6 An environmental risk ranking of pesticides 33

5. Water quality guidelines for pesticides 375.1 Australian water quality guidelines developed by ANZECC 375.2 Drinking water guidelines developed by NHMRC/ARMCANZ 385.3 Other points to consider 40

6. Monitoring and sampling of pesticides 426.1 Sources of pesticide contamination in drainage waters 426.2 Sampling techniques 436.3 Sampling frequency 446.4 Assessment techniques 45

7. Pesticide concentrations in the irrigation areas of S-W NSW, a review of data 517.1 MIA surface water quality project 1991-93 517.2 MIA surface water quality project, 1994-95 537.3 CIA surface water quality data report 1991-93 547.4 CIA surface water quality monitoring 1994-95 567.5 Murray Valley surface water quality report 577.6 Toxicity of rice and maize pesticides from 5 farms at Willbriggie, MIA 587.7 Pesticide dissipation in rice bays 667.8 Pesticides in drainage water leaving individual farms 687.9 Pesticide export from a rice-pasture area - 1991 sampling 697.10 Pesticide export from a rice pasture area - 1993-94 sampling 717.11 Runoff from summer cropping (maize) 727.12 Tile drainage from horticulture 727.13 Surface water runoff from a citrus farm 737.14 Grab samples from Mirrool creek, 1991 737.15 Mirrool Creek study, Oct-Dec 1994 747.16 The impact of pesticides used in rice agriculture on larval chironomid

morphology83

7.17 Groundwater contamination 83

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7.18 Pesticide concentrations in soil 847.19 Pesticide concentrations in biota 857.20 Surveys of pesticide residues in food 857.21 Monitoring pesticide residues in drinking water 877.22 Cholinesterase levels in farmers of the MIA 887.23 Other uses of agricultural pesticides 887.24 Other pesticide studies by the CSIRO Laboratory in Griffith 89

8. Reducing the impact of pesticides 918.1 More efficient use of pesticides 918.2 More efficient irrigation techniques 938.3 On-farm water re-use schemes 948.4 Whole farm planning 958.5 Alternative pest management methods 958.6 Handling and disposal of pesticides 968.7 Regional water re-use schemes 978.8 Vegetation in drains 978.9 Constructed and managed wetlands 978.10 Land & Water Management Plans 988.11 Maintaining a ‘clean green’ image 98

9. Future research 999.1 Alternative pest control methods 999.2 Pesticide monitoring studies 999.3 Ecotoxicology and pesticide impact on aquatic food webs 1009.4 Analytical techniques 1019.5 Other issues 101References 102AppendicesA) Details of pesticide use patterns for the main irrigated cropsB) Solubilities in water of the common pesticidesC) Information on the monitoring of drinking water for pesticide

contaminationD) Raw data from CSIRO pesticide monitoring programs

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EXECUTIVE SUMMARY

While many agricultural industries have taken measures to reduce pesticide use in recent years,problems can still arise when these chemicals are dispersed beyond their target area. This isparticularly so in irrigation areas, such as those in south-western NSW, where there is a risk ofpesticides entering local waterways via tile drainage or surface runoff from irrigated fields.

Information is sought by environmental managers on the pathways by which pesticides leave the site ofapplication and the resulting concentrations in nearby streams, lakes and rivers. This data is essentialfor assessing the environmental impacts and developing best management practices.

The aim of this report was to provide such information for the irrigation areas of south-western NSW,and includes details of:• Pesticides most commonly used,• Pesticide toxicity to aquatic organisms,• Monitoring and sampling techniques,• Pesticide monitoring studies carried out by the CSIRO and other agencies from 1990 to early 1995,• Strategies and guidelines that will help reduce contamination.

Quantities of pesticides used in 1994-95Since there were no records of the actual quantities of pesticides used each season on the irrigationfarms, these were estimated by obtaining information on; the areas of each crop grown, the standardapplication rates of pesticides used on each crop, and the average number of sprays per season.

The most commonly used herbicide was molinate which was applied to rice crops throughout theirrigation areas of S-W NSW. Other herbicides commonly used in the irrigation areas were theknockdown herbicides (such as glyphosate, diquat and paraquat) which were used for general weedcontrol and seed-bed preparation for a variety of crops, and the soil applied herbicides such as atrazineand diuron.

Despite relatively low rates of application per hectare, the greatest quantities of insecticides were usedon rice crops due to the large areas grown. These included malathion, chlorpyrifos and trichlorfon.Chlorpyrifos was also used on a range of other crops such as cereals, canola, maize, grapes andvegetables. Other common insecticides were endosulfan (which was used on canola, maize andvegetables) and pyrethroids such as cypermethrin and deltamethrin.

Fungicide use varies greatly from season to season depending on the weather. The largest quantitiesused in the MIA were on grapes, vegetables and stone fruit. The most common types included coppercompounds, mancozeb, metalaxyl, chlorothalonil, benomyl and sulphur compounds.

Pesticide toxicityThe insecticides most toxic to aquatic fauna, and commonly used in the irrigation areas, werechlorpyrifos and endosulfan both of which have LC50s of 0.1 µg/L or less. Other insecticides with lowLC50s included malathion (0.6 µg/L), parathion (0.6 µg/L) and the pyrethroids deltamethrin (0.4µg/L), fenvalerate (0.7µg/L) and lambda-cyhalothrin (0.3 µg/L).

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Generally most herbicides tend to be less toxic than insecticides to the aquatic fauna in rivers andstreams. However, many herbicides (such as atrazine), can be highly toxic to aquatic plants and algae.These herbicides have the potential to alter the food webs and the structure of aquatic ecosystems byeliminating the more sensitive plant species.

An environmental risk ranking of pesticidesThe Commonwealth Environment Protection Agency (CEPA) introduced a process (developed by theUSEPA) to predict the environmental hazard of pesticides to water bodies. This method was applied tothe pesticides commonly used in the irrigation areas of S-W NSW, and the calculated hazard ratings (orQ values) indicate that endosulfan and chlorpyrifos posed the highest environmental risk to aquaticecosystems. Other pesticides with high hazard ratings include carbaryl, malathion, deltamethrin,parathion, benomyl and dimethoate. Although the herbicides atrazine and diuron had hazard ratingswhich are lower than many other pesticides, they posed an environmental risk due to their persistenceand mobility in both surface water and groundwaters. Molinate also deserved special mention, since itwas detected in most irrigation drains during October-December when it was being applied to ricefields, and often exceeded guidelines both for drinking water and for the protection of the aquaticenvironment.

Sampling of drainage water for pesticide analysisWhen developing a sampling protocol, consideration should be given to the best sampling location, thefrequency of sample collection, the type of sampling vessel used, sample preservation, and the holdingtime prior to analysis.

While manual ‘grab’ samples are commonly used for pesticide analysis, automatic samplers offerconsiderably more scope, particularly for sites that may be remote or when human resources arelimited. Sampling frequency and mode can easily be adjusted to a predetermined regime to maximisereturn of information and minimise sampling effort.

Sampling frequency is a major consideration when establishing a sampling protocol for the detection ofpesticides in waters. A monitoring regime based on the use of autosamplers for the collection ofcomposite samples every 2 to 8 days was determined to be the minimum required to obtain a reasonablyaccurate reflection of pesticide contamination in irrigation drainage water.

Pesticide assessment techniquesTechniques based on analytical chemistry have, until recently, been the basis of most water qualitymonitoring protocols for the assessment of pesticide contamination. Biological techniques to assesswater quality (such as biosurveys and ecotoxicology) are assuming greater importance in recognition ofthe fact that the quality of water is reflected in the type and abundance of aquatic biota that is present.However, a combination of both techniques is often required to fully assess the impact of pesticides onthe aquatic environment and to identify the likely cause.

Immunoassay Techniques (or Enzyme Linked Immunosorbent Assays) are a form of bioassay whichrelies on the formation of antibodies to a pesticide antigen in mammalian blood. The main advantagesof this technique are the relatively low cost and that it can be carried out in the field semi quantitatively.Some disadvantages are the need for several different kits to screen mixtures of compounds, and thatcross reactivity of pesticides with similar three dimensional shapes can occur.

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Review of pesticide monitoring dataA review of the pesticide monitoring that has been carried out in the irrigation areas of south-westernNSW by Government agencies and the CSIRO was undertaken. A summary of the main findings ispresented below:

Supply water from the Murrumbidgee or Murray RiverWater taken from the Murrumbidgee or Murray River is of a high quality, and generally no pesticideswere detected. The only exceptions were;• September 1992, when atrazine was detected at a level of 0.08 µg/L in the Main Supply channel at

Yanco,• January 1994, when endosulfan sulphate at a level of 0.02 µg/L was detected in the Coleambally

supply channel (at Sturt Highway),• Mulwala supply offtake on the Murray River tested positive on three occasions during 1990-94,

with three different pesticides being detected; atrazine (one detection at 0.2 µg/L), molinate(twodetections at 7.2 µg/L and 0.5 µg/L) and 2,4-D (one detection at 0.5 µg/L).

Supply water within the irrigation areasAs supply water enters the irrigation areas, there is the potential for it to become contaminated with lowconcentrations of pesticides due to spraydrift or overspray. Also, in some regions the supply water isshandied with drainage water from upstream irrigation areas. Pesticide contamination of these shandiedsupplies is common, as shown by measurements of supply water for the farms in the Willbriggie districtwhere supply water is shandied with MIA drainage water via the Sturt canal. Maximum concentrationsdetected (µg/L) and the proportion (%) of samples in a 55 day monitoring period with detectable levelsof each pesticide, were as follows: atrazine 0.35 µg/L (20%); malathion 0.06 µg/L (2%); chlorpyrifos0.05 µg/L (2%); molinate 3.6 µg/L (90%). The maximum chlorpyrifos concentration was fifty timeshigher than the guidelines for ecosystem protection, but well below the NHMRC drinking waterguideline of 10 µg/L. The high frequency of molinate contamination was due to the measurementsbeing taken in spring and early summer when this herbicide was being applied to rice crops.

Pesticide levels in large drainage channelsWater in the large drainage channels contain runoff from a variety of crops, and pesticide residues werepresent, particularly in spring and summer. Molinate was detected in most drains during October-December when it was being applied to rice fields, and often exceeded guidelines both for drinkingwater and for the protection of the aquatic environment. Other pesticides commonly detected at levelswhich exceeded the guidelines for ecosystem protection were; diuron, atrazine, endosulfan, chlorpyrifosand malathion. Less frequently detected pesticides which have been found to exceed guidelines forecosystem protection, included thiobencarb, metolachlor, bensulfuron methyl, diazinon and MCPA.

Tile drainageTile (sub-surface) drainage water was monitored for bromacil and diuron at 49 horticultural farms inthe MIA on three occasions in 1992 (January, May and August). Approximately 28% of the 49 farmsmonitored, contained detectable levels of both bromacil (>0.50 µg/L) and diuron (>0.05 µg/L).Furthermore, an additional 10% of the farms showed detectable levels of just one compound.Maximum concentrations detected for bromacil and diuron were 11 and 28 µg/L respectively.Investigation of on-farm management practices indicated that those farms using these herbicides tocontrol weeds were likely to have detectable levels of these compounds in their sub-surface drainagewater.

Pesticide contamination of groundwaterThe Australian Geological Survey Organisation conducted some testing of shallow groundwater (0.9 -7.1 metre depth) in the Berriquin and Denimein Irrigation Districts. Pesticide compounds were detected

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in 5 out of 16 bores, although the concentrations were very low. Desethylatrazine (DEA), a metaboliteof the triazine herbicide atrazine, was present in three samples although the parent compound was notdetectable. Other compounds detected were the herbicides simetryn and trifluralin.

Reducing the impact of pesticidesMuch can be done through the adoption of best management practices to minimise drainage volumesand chemical loads leaving individual farms and also to prevent drainage water from reaching naturalwaterbodies. Many agricultural industries have already adopted best management practices and havesignificantly reduced pesticide loads entering rivers. Some of these practices are:

a) More efficient use of pesticides. This will not only result in more effective pest control but will alsoreduce the risk of environmental contamination. This includes the following practices;• Choosing the most effective pesticide for the weed or insect being targeted.• Only applying pesticide when it is required.• Using the recommended rate of application.• Applying the pesticide at the correct time of season.• Applying the pesticide only if the weather is suitable.• Avoiding spray drift and overspraying of drains.• • Using the most efficient application methods and equipment.

b) Increasing irrigation efficiency minimises the total load of pesticides (and nutrients) in drainagewater since there will be less runoff (tailwater) leaving the field. More efficient irrigation not onlyreduces the impact of pesticides on the environment but also provides financial benefits by reducinglosses of valuable chemicals from the field, and reducing irrigation water requirements.

c) Water re-use schemes can greatly reduce (or eliminate) the amount of drainage water, and associatedcontaminants, leaving irrigated farms. The simplest form of water re-use is the diversion of drainagewater to irrigate further crops or pasture. Other schemes consist of an enlarged drainage sump whichcan be pumped out into adjacent supply channels. In other areas, drainage can be pumped into damswhere it is stored for later gravity diversion and shandying with supply water.

d) A whole farm plan is essential to maximise the effectiveness of irrigation techniques, irrigationscheduling, and drainage water re-use schemes. Productivity and efficiency gains from developing awhole farm plan can be considerable.

e) Alternative pest management methods. This approach often makes good economic sense since it canreduce the need for expensive chemical applications. In addition, produce can be marketed ascontaining less chemicals and may command a premium price. Many agricultural industries areactively reducing their pesticide use, some very successfully.

f) Regional water re-use schemes utilise drainage water before it enters a major watercourse, therebyreducing the total volume discharged. This already occurs in several parts of the Murray-Darling Basinincluding the downstream regions of the Murrumbidgee Irrigation Area in NSW, and sections of theGoulburn and Kerang regions of northern Victoria.. Water re-use schemes will become increasinglyattractive if upstream farmers can reduce the loads of contaminants entering drainage water, thusreducing the risk of water quality problems when water is re-used on crops or for stock and domesticpurposes by downstream farmers.

j) Land & Water Management Plans. Some communities, with assistance from governments, have setup Land & Water Management Plans. This leads to a catchment based management plan containingrecommended actions and implementation targets aimed at sustainable land use and reliable water

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quality. Land & Water Management Plans are being developed for each of the three main irrigationareas in south-western NSW; the MIA, CIA and Murray Valley.

k) Maintaining a ‘clean green’ image: If the agricultural industries in the irrigation areas of S-W NSWare to expand their markets both within Australia and overseas, it is essential that the region maintainsa ‘clean green’ image. This requires co-ordinated action by growers, government authorities andresearch institutions to implement effective pesticide reduction programs.

Future researchTo determine the full impact of pesticides on aquatic ecosystems in the irrigation areas of S-W NSW,and develop better farm practices for the reduction of pesticide contamination, the following researchneeds to be pursued.

a) Alternative pest control methods.• Development of alternative pest control methods will reduce the need for pesticides. This includes,

- integrated pest management strategies,- biological pesticides (such as Bacillus thuringiensis),- soft chemical alternatives (eg white oil on citrus),- research into identifying biological controls (such as the use of predators),- encouraging the use of low chemical regimes and organic farming practices.

• Development of new pest resistant crops to reduce or eliminate the need for pesticides.

b) Pesticide monitoring studies• The impact of pesticides on the major rivers. Most monitoring work has concentrated on

measuring the concentrations of pesticides in drainage channels within the irrigation areas. Futuremonitoring should also focus on determining the quantities (and resulting ecological impacts) ofpesticides entering the major rivers in the region.

• Pesticide loads entering waterways during storms. High concentrations and large quantities ofpesticides can enter waterways during high flow events.

• Pesticides in runoff from dryland farms. Monitoring of runoff from dryland farming needs to beundertaken to determine the level of pesticide contamination entering streams and rivers in theMurrumbidgee and Murray catchments.

• Crop specific data. This would help identify any problems of pesticide contamination associatedwith particular crops, and could be used to develop better management practices.

• Different irrigation regions. Much of the pesticide monitoring in S-W NSW, and in particular thework undertaken by the CSIRO, has been centred around the MIA. Future monitoring shouldinclude more studies in the Coleambally and Murray Valley Irrigation Areas to help develop a morebalanced perspective of pesticide contamination of all regions.

• Calculation of pesticide loads entering waterbodies , not just concentrations. Monitoring programsshould always endeavour to collect flow data so that the total pesticide loads entering rivers andstreams can be calculated.

• Monitoring of pesticide residues in sediments. It is recommended that general monitoring schemes

should examine sediments for pesticide accumulation, and the resulting impact on benthicorganisms.

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c) Ecotoxicology and pesticide impact on aquatic food webs.• Research into the impact of pesticides on the aquatic food webs, including species higher up the

food chain such as frogs, waterfowl and other vertebrates. Other parts of the food web that needfurther study include the impact that herbicide residues have on aquatic plant communities of therivers and lakes in the region.

• Impacts of pesticide additives. Very little information is available on the impact that the chemicalsadded to pesticide formulations might be having on aquatic ecosystems in the irrigation areas.

d) Analytical techniques• Immunoassays. Further development is needed so that a much wider range of pesticides can be

tested using these techniques.

• Automatic monitoring stations Another area for future research is the development of automaticpesticide monitors which could be placed in waterways and continuously record the pesticideconcentrations of the water. The data could then be transmitted to a central office for assessmentby the local water authority.

e) Other issues• Developing ways to get a strong message across to landholders and commodity groups to change

farming practices. Techniques being used in other countries (such as Sweden, Denmark, theNetherlands and the USA) should be reviewed.

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1. INTRODUCTION

The use of pesticides has increased substantially in the last 4 decades and has contributed to bothincreased crop yields and decreased production costs. However, pesticides also pose a threat to boththe environment and human health. While many agricultural industries have taken measures to reducepesticide use in recent years, problems can still arise when these chemicals are dispersed beyond theirtarget area. This is particularly so in irrigation areas, such as those in south-western NSW, where thereis a risk of pesticides entering local waterways via tile drainage or surface runoff from irrigated fields.

Information is sought by environmental managers on the pathways by which pesticides leave the site ofapplication and the resulting concentration in nearby streams, lakes and rivers. Such data is essentialfor assessing the environmental impacts and developing best management practices. The aim of thisreport was to provide such information for the irrigation areas of south-western NSW, and includesdetails of:• Pesticides most commonly used on irrigated crops in south-western NSW,• Pesticide toxicity to aquatic organisms,• Monitoring and sampling techniques,• Pesticide monitoring studies carried out by the CSIRO and other agencies in the irrigation areas of

south-western NSW from 1990 to early 1995.• Strategies and guidelines that will help reduce contamination.

The report concentrates on the use of pesticides on irrigated farms and does not address issues relatingto pesticides use in dryland farming, or the use of chemicals in urban and industrial areas of theregional towns,

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2. IRRIGATION AREAS OF SOUTH-WESTERN NSW

2.1 Location and size of irrigation areas and districts

Irrigation farms in south-western NSW are located in both the Murrumbidgee and Murray Valleys, andin 1994 covered a total of 1.3 million hectares (Figure 1a, 1b). In the Murrumbidgee Valley, irrigationfarms are located in eight main regions, and in 1994 covered 560,700 hectares (Table 1).

Table 1. Irrigation Farms in the Murrumbidgee RegionIrrigation area or district Number of

farmsTotal area of

farms (ha)Yanco Irrigation Area 1,173 88,760Mirrool Irrigation Area 1,249 74,791Coleambally Irrigation Area 345 79,161Hay Irrigation Area 64 1,252Benerembah Irrigation District 138 44,235Wah Wah Irrigation District 151 261,955Tabbita Irrigation District 22 10,473Gumly Irrigation District 51 137Total 3,193 560,764

(source: NSW DWR 1993-94 Annual Report)

In the Murray Valley there were 716,000 hectares of irrigation farms located in the following regions;

Table 2. Irrigation Farms in the Murray RegionIrrigation area or district Number of

farmsTotal area of

farms (ha)Tullakool Irrigation Area 18 6,326Berriquin Irrigation District 1,406 321,504Deniboota Irrigation District 275 132,318Denimein Irrigation District 164 53,021Wakool Irrigation District 338 202,524Total 2,201 715,693


There were also a small number of farms in the Lower Murray-Darling Region covering an area of4,200 hectares (Table 3)

Table 3. Irrigation Farms in the Lower Murray-Darling RegionIrrigation area Number of

farmsTotal area of

farms (ha)Buronga 26 361Coomealla 277 2,788Curlwaa 123 1,107Total 426 4,256


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Figure 1a: Irrigation Areas of south-western NSW

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Figure 1b Murrumbidgee Irrigation Areas and Districts (source; MDBC 1992)

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2.2 Types of irrigated crops grown

Broadly speaking, there are two types of irrigation farms. Firstly, there are small area farms (orhorticultural farms) which average 15-20 hectares in area, most of which are centred around thetownships of Griffith and Leeton, and have permanent plantings of citrus, stone fruit, and grapes.Secondly there are large area farms of 200-300 hectares on which rice, winter cereals, row crops andpasture are the major crops. However, in the last few years the difference in the two types of farms hasbecome less distinct, with the expansion of permanent horticulture (mostly grapes) onto large areafarms in the MIA. Table 4 provides information on the major irrigated crops grown in 1994.

Table 4 Major irrigated crops of south-western NSW in 1994crop MIA

(hectares)

Hay

(hectares)

CIA

(hectares)

MurrayValley

(hectares)

LowerMurray

(hectares)

TOTAL

(hectares)rice 37,000 5,500 24,000 54,000 120,500winter cereals 20,000 24,000 23,000 67,000vegetables 5,650 500 1,015 7,165soybeans 2,500 100 2,600citrus 9,000 1300 10,300grapes 6,500 2350 8,850maize/sorghum 2,000 3,900 600 400 6,900canola 4,000 2,000 2,000 8,000stone fruit 900 40 940

(information obtained from technical officers of NSW Agriculture in the Murray and Riverina regions)

2.3 Supply of water to irrigation farms

The farms in the Murrumbidgee Valley receive water from the main supply channel which diverts waterfrom the Murrumbidgee River at the Berembed Weir, east of Narrandera. The Mirrool and YancoIrrigation Areas take water directly from the main supply canal and hence receive high quality water.The Wah Wah and Benerembah Irrigation Districts however, receive a lower quality mixture ofdrainage water (from the Mirrool and Yanco Irrigation Areas) and fresh supply water.

The Coleambally Irrigation Area receives high quality water via a main supply channel from theMurrumbidgee River commencing at Gogeldrie Weir near Leeton. Some farms in this region also usebore water for irrigation. This is obtained from a sand aquifer approximately 150 metres below thesurface and is high quality water. Farms downstream of the CIA re-use much of the drainage waterleaving the irrigation area.

The irrigation farms in the Murray Valley obtain water from the Murray River via the Mulwala supplychannel and from water diverted into the Edward River system. As with the Murrumbidgee andColeambally irrigation areas, the downstream farms often receive a mixture of fresh supply water andlower quality drainage water.

An increasing percentage of farms in both the Murrumbidgee Valley and the Murray Valley arecollecting drainage water from their farms and recycling it back onto crops. Recycled water tends to beof a poorer quality due to higher salinities and might also contain low concentrations of pesticides.

Finally, a sizeable number of farms which border either the Murray River or the Murrumbidgee Riverobtain water by pumping directly out of the river.

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2.4 Disposal of drainage water from irrigation farms

There is a considerable volume of excess water generated by the irrigation farms which collects inirrigation drains. The main sources of drainage water are;

• surface runoff (both irrigation tailwater and stormwater) from irrigated fields and crops,• water from subsurface drains (or tile drains) which have been constructed under permanent

horticulture to control waterlogging and salinity problems,• excess water which overflows from the irrigation supply channels.

Most of the drainage waters leaving the Mirrool and Yanco Irrigation Areas flow west towards BarrenBox Swamp and are re-used in the Benerembah and Wah Wah Districts. On a few occasions duringwet weather, excess drainage water leaving Barren Box Swamp has passed through the Lower MirroolCreek floodplain and reached the Lachlan River system. There is also some drainage water from thesouthern part of the Yanco Irrigation Area that flows south into an anabranch of the MurrumbidgeeRiver; most of which then enters the Sturt supply channel, although on occasions (such as wet weather)will flow into the main river channel.

Drainage from Coleambally Irrigation Area is returned to the Edward River via Yanco and Billabongcreeks. However, much of this drainage water is re-used by downstream landholders before it reachesthe Murray.

In the Murray valley not all farms have access to drainage systems. Where drains do exist, theynormally run into the local creeks which in turn flow into the Edward River (and eventually back intothe Murray River). As with the Coleambally Irrigation Area, much of the drainage water gets shandiedwith supply water and is re-used by downstream farmers.

Virtually all drainage water in the Lower Murray Irrigation Areas (Coomealla, Curlwaa and Buronga)is discharged inland to Fletchers and Hollands Lake for disposal by evaporation.

Drainage water contains low concentrations of salt, nutrients, and also traces of pesticide residues.Therefore, if it is recycled on-farm or re-used by farmers downstream, care needs to be taken to ensurethat the salt or pesticide residues do not harm the crop and also meet drinking water guidelines.

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3 PESTICIDE USE IN THE IRRIGATION AREAS OFSOUTH-WESTERN NSW

In order to assess the environmental impacts of pesticide use in the irrigation areas of S-W NSW, it isimportant to have a good knowledge of the following points;

• what pesticides are most commonly used,• the crops they are applied to,• when the pesticides are used,• the application rate, and the number of applications per season,• the total quantity of pesticide used,• chemical and physical properties of each pesticide such as toxicity, persistence and solubility.

In this chapter an overview of the pesticides most commonly used in the irrigation areas of S-W NSWin 1994-95 is presented. This information (along with details of toxicity and persistence) will beapplied in later chapters for estimating the pesticides of greatest environmental impact (section 4.6).Details of what pesticides are used on each crop and when they are applied, is also useful whendesigning monitoring programs, in particular, determining where to locate monitoring stations, howfrequently to take samples, and what to analyse for (see Chapter 6).

3.1 Records of pesticide use patterns

The types of pesticides recommended for each crop and the application rate (in grams/hectare), werereadily available from the NSW Department of Agriculture. However, the actual quantities used by thefarmers varies from year to year depending on what crops they decide to plant, and what insect pests orweeds are causing a problem. There are no records available of the actual quantities used by eachfarmer, and this can only be estimated by the areas of each crop grown, the standard application rate,and the likely number of sprays per season. An alternative source of information on the quantities ofpesticides used would be from local retailers or manufacturers, however this information is not publiclyavailable.

It would be very useful for environmental managers if the pesticide industry could provide records ofuse patterns, enabling calculation of pesticide loads and environmental impact. While this might beseen as a retrograde step by some, it is necessary to guarantee proper use of an ever more complex andwide range of chemicals, and to ensure that Australian produce maintains a ‘clean’ image. Records ofpesticide sales could be maintained either by each farmer, or more simply by local retailers.

3.2 Pesticide use on a crop by crop basis

A summary of the pesticides used on the main irrigated crops of south-western NSW in 1994-95 ispresented below. For further details, refer to Appendix A.

RiceThe largest use of pesticides in the irrigation areas of S-W NSW was for the growing of rice. This wasdue both to the large area of rice grown (120,000 ha) and also the relatively high quantities applied perhectare. The main herbicides used were molinate and bensulfuron-methyl which were applied in

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October-November to control grasses and broadleaf weeds. The most commonly used insecticides weremalathion, chlorpyrifos and to a lesser extent trichlorfon, for the control of bloodworm or leaf miner.Other chemicals used included copper sulphate for the control of algae and snails.

Winter cereal crops (wheat, barley, oats)Large areas of cereals (67,000 ha) were grown during winter in the irrigation areas as a rotation cropon rice farms. Following rice cropping, pest problems are usually minimal, and it is common for nopesticides to be used. Remaining non-rice areas would have similar pesticide use to dryland cropping.However irrigation farms tend to avoid the sulfonyl urea and other residual herbicides because ofrestricted plant-back times which may interfere with summer cropping schedules. Typical herbicidesincluded MCPA, 2,4-D, diclofop and fenoxaprop. Insecticides are not usually needed althoughoccasionally chemicals such as chlorpyrifos, methomyl or fenvalerate might be used.

Irrigated pastureHerbicides were applied to pastures to selectively remove unwanted species. This was most common inhay-making enterprises where weed contamination affects quality. Knockdown herbicides were oftenapplied prior to cropping, either to kill off the pasture, or at low rates to reduce seed set (and thereforeseed carry-over). The most common herbicides used on pasture included MCPA, 2,4-D, glyphosate,dicamba, paraquat and diquat.

Insecticides were applied to pastures to control Red Legged Earth Mite or in rare instances plagues ofgrass hoppers, cut worm etc. Generally it is not economic to treat pastures except for high value areasgrown specifically for hay or intensive grazing (dairying). There are many insecticides that can beused, some of the most popular being chlorpyrifos, dimethoate, omethoate, fenitrothion andmonocrotophos.

CanolaCanola was planted at the end of autumn as a winter crop, with harvesting occurring in November.Pre-emergent herbicides such as trifluralin, and post-emergent herbicides such as fluazifop-p-butyl andclopyralid were used to control weeds. Insecticides were applied from May-October and includedchlorpyrifos, endosulfan, lambda-cyhalothrin and dimethoate

SoybeansSoybeans are a summer crop and are mainly grown in the Coleambally Irrigation Area. The total areaplanted varies greatly from season to season depending on market prices. Both pre-emergenceherbicides (such as trifluralin), and post emergence herbicides (such as sethoxydim, fluazifop-p-butyland haloxyfop) were used for grass weed control. Insecticides such as endosulfan, methomyl and arange of pyrethroids (cypermethrin, deltamethrin, and lambda-cyhalothrin) were used to controlheliothis, green vegetable bug and a range of other insect pests.

Maize and sorghumMaize and sorghum are summer crops grown in the MIA, CIA, Murray valley and near Hay. Sorghumis generally not grown in large areas although this does vary depending on market prices. The mainherbicide used is either atrazine or a mixture of atrazine and metolachlor. Insecticides, includingendosulfan, chlorpyrifos and pyrethroids were used to control pests such as heliothis and armyworms.

GrapesMost grapes were grown on horticultural farms near the townships of Griffith and Leeton. However,quite a few new vineyards were being established, and many of these were located on large area farmswithin the MIA. Herbicides such as glyphosate, oryzalin, simazine and paraquat/diquat were applied inAugust-September to eliminate any weeds that have established over the winter months. Insecticide usewas declining as farmers turn to other methods of control, especially biological control methods. Themain pest is the light brown apple moth and grape vine moth which can be controlled by the biologicalinsecticide, Bacillus thuringiensis or by synthetic insecticides such as chlorpyrifos and malathion.Sulphur sprays, dicofol and carbaryl were used to control mites. In most years the threat of fungal

18

outbreaks is a problem and fungicides such as copper sprays, sulphur sprays and mancozeb are usuallyapplied. Insecticides and fungicides are applied between October and March.

Citrus and stone fruitCitrus crops were located in the horticultural areas near Griffith and Leeton. Bromacil and diuron werethe most common herbicides used to control weeds. Often no insecticides were used apart fromsummer oil for scale control. Copper compounds were seasonally applied to control fungal outbreaks.

The stonefruit industry is located in the MIA and centred mainly around Griffith and Leeton. In 1994-95, there were uncertainties in the industry and the areas planted had declined. There were manypesticides registered for use on stonefruit, but most were only used occasionally. Fungal diseases werethe main reason for spraying which in a wet year can be intensive. To counter resistance, most growersalternate between the different product groups. Typical fungicides used include chlorothalonil,mancozeb, benomyl, copper compounds, zineb and propiconazole. In a dry season few sprays areapplied.

VegetablesMost of the vegetable crops were grown in the MIA (and to a lesser extent the Murray Valley), and in1994-95 covered a total area of approximately 6000 hectares. Vegetable production was steadilyincreasing, although it can vary from year to year depending on market conditions. The main cropswere tomatoes, cucurbits (such as rock melons, water melons and pumpkins), onions, potatoes andcarrots. A wide range of herbicides (such as fluazifop-p-butyl, trifluralin and linuron), insecticides(such as chlorpyrifos, endosulfan and dimethoate) and fungicides (such as mancozeb, copper andsulphur compounds) were used, depending on the type of vegetable grown, the seasonal conditions, andwhich pests were causing a problem.

Knockdown herbicidesSeveral knockdown herbicides were widely used in agricultural systems for cleanup and seed-bedpreparation work. Which product is used depends on weed spectrum, growth stage and season ofapplication. These herbicides have become essential tools in most operations. In horticulture,knockdown herbicides were used mainly for cleanup work along headlands, channels, drains and undertree/vine plantings. In field cropping systems they were used for similar cleanup work, but their mainuse is for seed-bed preparation where large quantities were used.

Seed-bed preparation using knockdown herbicides has become universal, the advantage being timelinessof planting, speed of ground preparation, cost savings over cultivation, guaranteed weed kill in wetconditions, elimination of erosion, and soil structure preservation. The two most widely used productswere the bipyridyls (diquat and paraquat) and glyphosate. The bipyridyls were most widely used inwinter (work better under low light intensity) whilst glyphosate was used widely during summer.Glyphosate was the preferred product for general cleanup work because of its safe handling andeffectiveness on perennials.

Seed dressingsPractically all seeds sown commercially are treated with fungicide seed-dressing compounds to controlseed-borne diseases. The seed-dressing might also contain insecticides to control soil active insects. Alist of pesticides used as seed dressings are presented in Appendix A.

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3.3 Summary of pesticides most commonly used

Tables 5 and 6 provide a summary of the pesticides most commonly used in each of the major irrigationareas in 1994-95. These lists have been compiled by considering the types (and area) of crops grown,and the types, application rates and frequency of pesticides applied to each crop. As mentionedpreviously, much of this information can only be estimated, and hence these lists are not definitive.Knowing which pesticides are used most often (and in what season) is essential information whenplanning a monitoring program, or assessing which pesticides may have the greatest impact on theenvironment.

The largest use of herbicides in the irrigation areas of S-W NSW was for the growing of rice. Thisreflects both the large area of rice grown and also the relatively high quantities applied per hectare.Although the herbicide molinate was only used on rice, the total quantities applied each season(>100,000 kg in the MIA alone) far exceeded any other herbicide. Bensulfuron-methyl was anotherherbicide used by many farmers on rice crops.

Other herbicides commonly used in the irrigation areas were the knockdown herbicides (such asglyphosate, diquat and paraquat) which were used for general weed control and seed-bed preparationfor a variety of crops, and the soil applied herbicides such as atrazine and diuron.

Despite relatively low rates of application per hectare, the greatest quantities of insecticides were usedon rice crops due to the large areas grown. These include malathion, chlorpyrifos and trichlorfon.Chlorpyrifos was also used on a range of other crops such as cereals, canola, maize, grapes andvegetables. Other common insecticides were endosulfan (which is used on canola, maize andvegetables) and pyrethroids such as cypermethrin and deltamethrin.

Fungicide use varies greatly from season to season depending on the weather. The largest quantities areused in the MIA on grapes, vegetables and stone fruit. The most common types included coppercompounds, mancozeb, metalaxyl, chlorothalonil, benomyl and sulphur compounds.

Table 5 Pesticides most commonly used in the MIA in 1994-95herbicides crops applied to; insecticides crops applied to;2,4-D winter cereals, pasture carbaryl grapes, cucurbitsacrolein aquatic weed control chlorpyrifos rice,cereals,canola,maize,vegetablesatrazine maize cypermethrin maize, vegetablesbensulfuron methyl rice deltamethrin maize, vegetablesbromacil citrus dimethoate vegetablescopper rice (algae control) endosulfan canola, maize, vegetablesdiquat general use fenvalerate winter cerealsdiuron citrus malathion rice, citrus, cucurbitsfluazifop-p-butyl canola, vegetables summer oil citrusglyphosate general use trichlorfon riceMCPA rice, cereals, pasturemetolachlor maize fungicidesmolinate rice benomyl grapes, vegetables, stone fruitoryzalin grapes chlorothalonil grapes, stone fruitparaquat general use copper citrus, grapes, vegetables, stone fruitpropanil rice mancozeb grapes, vegetables, stone fruitsimazine grapes metalaxyl grapes, vegetablesthiobencarb rice sulphur compounds grapes, vegetablestrifluralin canola, vegetables

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Table 6 Pesticides most commonly used in the CIA and Murray Valley in 1994-95herbicides crops applied to; insecticides, crops applied to;2,4-D winter cereals, pasture chlorpyrifos rice,cereals,canola,maize,vegetablesacrolein aquatic weed control endosulfan canola, maize, soybeans, vegetablesatrazine maize malathion ricebensulfuron methyl rice methomyl maize, winter cereals, soybeanscopper rice (algae control) trichlorfon ricediclofop winter cereals deltamethrin soybeans, maize, vegetablesdiquat general use cypermethrin soybeans, maize, vegetablesglyphosate general use fenvalerate winter cerealsMCPA rice, cereals, pasturemetolachlor maize fungicidesmolinate rice mancozeb soybeans, vegetablesparaquat general use copper vegetablespropanil ricethiobencarb ricetrifluralin canola, soybeans

3.4 Adjuvants

Most pesticide formulations contain additives (or adjuvants). These are necessary to enhance activityor to enable mixing of an otherwise insoluble active ingredient. Adjuvants may include wetting agents,emulsifiers, dispersing agents, penetrants, anti-foam agents, inert carriers, buffering agents, stickers,petroleum solvents and other specialised formulating products. The amount of these products in eachformulation varies considerably, but can comprise more than half of the final product applied to a crop.There is therefore considerable quantities of these products used in the environment. However, theirimpact and fate does not seem to be widely considered. The importance of considering the impact ofthe additives as well as the pesticide, is demonstrated by comparing the toxicity of glyphosate with thatof the commercial formulations (pesticide plus a surfactant);

organism chemical 24 hr LC50rainbow trout surfactant 2.1 mg/L

glyphosate 140 mg/LRoundupR 8.3 mg/L

fathead minnow surfactant 1.4 mg/Lglyphosate 97 mg/LRoundupR 2.4 mg/L

(data from Trotter et al. 1990)

Unfortunately, in most cases it is not possible to determine from the label what adjuvants have beenadded.

At the farm level, wetting agents are the most commonly added adjuvant. These are necessary to enablestandard formulations to give adequate coverage on hairy or waxy plants, or to copewith other local problems such as hard water. Some products require the addition of petroleum basedcrop oils instead of wetters. Crop oils are widely used with the grass selective herbicides likesethoxydim and fluazifop-p-butyl when used on broadacre broadleaf crops such as lupins, canola, fababeans and peas. Commonly available wetters are listed in Appendix A.

21

3.5 Aquatic weed control

Another important use of herbicides is the control of aquatic weeds in channels to enable better flow ofwater. Both drains and supply channels are treated once or twice per year.

The herbicide most commonly used by the irrigation agencies for the control of submerged and floatingweeds in supply channels is acrolein, which is directly injected to the flowing water. In NSW acroleinis usually applied at a concentration of between 2-20 mg/L for 1-8 hours. This allows weed growth tobe controlled in approximately 10 km of channel. As treated water passes downstream the acroleingradually evaporates, so the concentration is steadily reduced. Acrolein contaminated supply water isdiverted into drainage channels via escape points.

For control of emergent weeds along channels, glyphosate is used, and to a lesser extent 2,2-DPA andamitrole. Soil residual herbicides such as diuron and atrazine are used by some farmers (sometimes atvery high rates of application) to maintain season long weed control in on-farm channels.

3.6 Methods of pesticide application.

The most common method of pesticide application is spraying. The spray unit may be hand carried,attached to a tractor or mounted to an aircraft. Aerial spraying is the most common method on ricefarms in the Riverina, whereas the smaller horticultural farms use air-blast spray units attached totractors. Some pesticides (nematicides or herbicides) are applied directly into the soil rather thanapplied to the surface. Other pesticides, typically selective rice herbicides, may be applied directly withirrigation water, a process termed herbigation.

The method of application is an important factor in determining the amount of pesticide that misses thetarget area and becomes a potential source of contamination. Notably, the precision of ground basedapplication is greater than aerial spraying and has reduced risk of drift and overspraying (this assumesthat the groundrig is well maintained and properly used).

3.7 Other biologically active chemicals, and pesticides used in thepast.

Although this report focuses on pesticides used in agriculture, it should be noted that there are otherpollutants and sources of contamination that can impact on the aquatic environment in rural districts.Some of these are;

• effluent from intensive rural industries (avermectins, antibiotics),• nutrients from soil erosion and fertilizer,• sewage, stormwater,• metals and other pollutants in industrial effluents,• use of pesticides to control outbreaks of aquatic weeds (such as alligatorweed in Barren Box

swamp),• domestic use of pesticides on gardens and for the control of termites.

These other sources of pollutants also need to be considered when developing management plans andguidelines for aquatic systems within the irrigation areas of S-W NSW.

22

Contaminants such as metals, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls(PCBs) are not normally used on (or near) irrigation farms and are more likely to be associated with theindustrial pollution of large cities.

Copper however, which is commonly used as an algicide and fungicide is an exception, andaccumulation of this metal in soils used for growing crops such as grapes, citrus and stone fruit couldbe expected (see section 7.16). Some fungicides also contain low levels of zinc and manganese,however this is not expected to cause a problem in the soils of S-W NSW.

It is also worth noting that in some regions of NSW high cadmium levels in soils has been caused bythe large use of phosphatic fertilisers (Wade 1995). Plants can take up cadmium from the soil andsurveys at the Sydney Markets have detected some vegetables with cadmium levels above the maximumpermitted concentration (MPC). Further testing of cadmium levels in soils, particularly in areas wherevegetable crops are grown, is recommended.

Organochlorine pesticides were widely used prior to 1980 on many crops including rice, cotton,vegetables, fruit and maize, and also on livestock such as sheep, cattle and poultry (AustralianAcademy of Science 1972, NRA 1993). Residues of these pesticides can remain in the soil for manyyears and are still detected in some districts (see section 7.18).

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4. FATE AND BIOLOGICAL IMPACT OF PESTICIDES

4.1 Physical pathways for pesticide transport

In order to assess the environmental impact of pesticides, it is necessary to understand the pathways bywhich they are transported from the point of application to the surrounding environment (Figure 2).The pathway for a particular pesticide will depend on many factors including;

- application method,- weather conditions,- spray droplet size,- soil types,- when rainfall occurs or irrigation water is applied,- physical and chemical characteristics of the pesticide.

A summary of the major pathways by which pesticides are transported from the point of application arepresented below, with particular reference to the irrigation areas of S-W NSW.

Figure 2 Fate and transport pathways for pesticides in natural waters(adapted from Peterson & Batley 1993)

DustParticles

AIRAerial Drift

Rainfall,Overspray

Surface microlayer

DISSOLVEDSUSPENDED

PARTICULATE

BIOTA

Drainage Water

Drainage Water

Evaporation

PhotolysisWATER

Hydrolysis

MicrobialDegradation

SEDIMENTPARTICULATE

DISSOLVED INPORE WATER

BIOTA SEDIMENTMicrobial

Degradation

Photolysis

24

a) Spray drift and overspraying.With the exception of some herbicides which are applied directly to the soil, direct spraying of crops isthe normal method of application. During application, and especially if aerial spraying is used,overspraying and spray drift can result in pesticides reaching nearby water bodies. The extent of spraydrift is determined by droplet size and weather conditions. The environmental impacts of oversprayingand spray drift can be minimised by the use of buffer zones between water bodies and crops. Toprotect nearby residents from spray drift, the 1978 NSW Pesticides Act specifies a 150 metre bufferzone between aerial spraying and houses.

The aerial transport of pesticides (in particular endosulfan) from cotton farms has been investigated bythe University of Queensland (Woods 1995).

b) Pesticides in Surface RunoffSurface runoff due to storms or irrigation, will transport pesticides in both the dissolved form andattached to soil particles. The first flush of runoff immediately after pesticide application can containhigh levels of pesticides. The contaminated runoff flows into irrigation drains or local streams, whicheventually lead to waterbodies such as Barren Box Swamp or rivers such as the Murrumbidgee orMurray.

Inefficient methods of irrigation such as furrow irrigation, which often produce large quantities oftailwater, are much more likely to wash pesticides off the field (both in dissolved form and attached tosoil particles) than more efficient methods such as microsprays or drip irrigation where very littledrainage water leaves the field.

c) Percolation of pesticides into tile drainage and groundwaterSome pesticides may be leached from the soil surface by rain or irrigation water , and may percolatedown through the soil column. In many horticultural areas this will result in contamination of tiledrainage water. Shallow groundwater can also become contaminated, particularly if the pesticide hashigh solubility and does not attach strongly to soil particles. Atrazine for example, has been detected ingroundwater in many parts of the world, including the USA (USEPA 1990, Ritter 1990, Domagalski &Dubrovsky 1992, Hallberg 1989), Europe (Kuhnt and Franzle 1994, Croll 1991) and Australia (Bauldet al. 1992, Stadter et al 1992).

d) VolatilisationSome pesticides are relatively volatile and may evaporate either during spraying or from leaf surfacesand soil. These vapours can precipitate out, many kilometres from the point of application, although inmost cases the level of contamination is low (Tabatabai 1983). The problem is restricted principally tothe ester formulations of phenoxy herbicides (Peter Stoneman, NSW Agriculture, pers. comm.), and theherbicide 2,4-D has been known to damage sensitive crops such as grapes and tomatoes when appliedon nearby farms.

e) Application of pesticides to irrigation drains for weed controlAquatic plants in irrigation channels are often controlled by the application of herbicides. Thisincludes;• the direct spraying of emergent weeds along the channel banks with knockdown herbicides such as

glyphosate,• residual soil-applied herbicides such as atrazine or diuron, which are used when the channels are

dry,• the direct injection of herbicides such as acrolein to the flowing water to control submerged weeds.The residues of these herbicides not only affect the aquatic ecosystem but in some cases (eg. atrazineand diuron) can also harm crops if the water is re-used for irrigation.

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4.2 Partitioning of pesticides to soil or water

In an aquatic ecosystem most pesticides will be dissolved in the water or attached to soil particles whichare either suspended in the water column or have settled to the bottom. Insoluble compounds mightalso be present in a thin layer of organic scum on the water surface. The extent to which a pesticidewill partition into these various compartments depends largely upon its chemical properties. Althougha compound may be water soluble, there may be a preference for it to adsorb onto soil particles andhence be effectively removed from solution. Soil particles generally contain both mineral and organiccomponents, and it is the organic matter that binds (or adsorbs) most of these pesticides. Therefore,soils with high levels of organic matter tend to adsorb the greatest quantities of pesticides.

The adsorption of a pesticide into a soil is related to its hydrophobicity or its tendency to partition fromwater onto organic matter, and this is called the ‘soil organic carbon sorption coefficient’ (Koc). Itshould be noted that there are a number of other factors (apart from soil organic matter content) thatcan affect pesticide adsorption to a soil, including the soil pH, and the type of clay particles present.Therefore a wide range of Koc values have been reported in the literature, depending on the soil type andexperimental conditions used for the study. (The adsorption of a pesticide to organic matter is alsosometimes estimated by the octanol-water coefficient, Kow which measures the partitioning of apesticide between water and octanol, an organic liquid).

Pesticides which have a high Koc value, and hence are readily adsorbed onto soil particles, tend topersist in the environment for longer since they can be slowly released from sediments many weeks (ormonths) after the initial contamination. These pesticides do not readily dissolve in surface runoff, theycan still be transported to nearby streams or rivers attached to suspended soil particles. Pesticides withhigh Koc values are also more likely to be found in the organic microlayers (or scums) on the watersurface.

Pesticides with low Koc values stay in solution and will be present (in dissolved form) in surface runoff.These pesticides also have a greater tendency to leach through soil profiles and reach tile drainage orshallow aquifers. A list of Koc values for some commonly used pesticides is presented in Table 7.

Table 7 Koc values of some common pesticides.

Herbicide Koc insecticide, fungicide Kocparaquat 1,000,000 lambda-cyhalothrin 180,000diquat 1,000,000 cypermethrin 100,000glyphosate 24,000 endosulfan 12,400diclofop-methyl 16,000 chlorpyrifos 6,070trifluralin 8,000 fenvalerate 5,300fluazifop-p-butyl 5,700 parathion 5,000thiobencarb 900 dicofol 5,000diuron 480 mancozeb >2000bensulfuron-methyl 370 benomyl 1,900metolachlor 200 malathion 1,800molinate 190 chlorothalonil 1,380propanil 149 methidathion 400simazine 130 carbaryl 300atrazine 100 methomyl 72bromacil 32 metalaxyl 50MCPA (diethylamine) 20 dimethoate 202,4-D 20 trichlorfon 10Data obtained from Wauchope et al. (1992)

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4.3 Persistence in the environment.

There are many degradation processes which transform pesticides into new and potentially less toxicchemicals (or metabolites). The principal degradation process is the reaction with water, or hydrolysis.Photolysis (reaction with light) is also possible in surface waters. Biological degradation can beanother important degradation process especially in sediments. Figure 2 illustrates the degradationpathways for pesticides in natural waters.

The susceptibility of a pesticide to degradation is often described by its half-life (t1/2

), which is the time

for the concentration to degrade to half its initial value. Although pesticides are often assigned a singlevalue for the half life, it should be remembered that this value depends on the method of degradation(hydrolysis, photolysis, chemical or biological degradation), and also on environmental factors such astemperature and pH. Despite this limitation, the half-life is a good indicator of the pesticides which aremost likely to persist in the environment. In Table 8, estimates for half lives in soils are presented forsome commonly used pesticides.

It should be noted that most of these pesticides have considerably shorter half-lives in water.Endosulfan for instance, has a half life of only 2-3 days in water (Peterson and Batley 1991a)compared with 50 days in soil.

Table 8. Half lives of pesticides in soilHerbicide Half life

(days)insecticide, fungicide Half life

(Days)paraquat 1,000 metalaxyl 70diquat 1,000 mancozeb 70metolachlor 90 benomyl 67diuron 90 endosulfan 50atrazine 60 dicofol 45simazine 60 fenvalerate 35bromacil 60 chlorothalonil 30trifluralin 60 chlorpyrifos 30glyphosate 47 lambda-cyhalothrin 30diclofop-methyl 30 cypermethrin 30MCPA (diethylamine) 25 methomyl 30thiobencarb 21 parathion 14molinate 21 carbaryl 10fluazifop-p-butyl 15 trichlorfon 102,4-D 10 methidathion 7bensulfuron-methyl 5 dimethoate 7propanil 1 malathion 1Data obtained from Wauchope et al. (1992)

4.4 Pesticide Toxicity.

Toxicity of pesticides to aquatic life can be described as either chronic or acute. Chronic toxicitygenerally involves sub-lethal effects such as physical deformities or reduced fertility, whereas acutetoxicity causes a measurable mortality over a short period of time. The dissolved concentrations of apesticide resulting in acute toxicity are generally assessed from laboratory tests and are reported as theconcentration that results in 50% mortality (LC50) within a given time such as 24, 48 or 96 hours.Chronic toxicity is reported in a similar way, as the concentration that causes a nominated symptom oreffect in 50% of a test population (EC50). The Aquatic Information Retrieval System (AQUIRE)

27

database from the US EPA Environmental Research Laboratories in Duluth, contains a vast amount ofthe published toxicity data, and can be accessed publicly from Australia.

Tables 9 and 10 present toxicity data obtained from the AQUIRE database and other publishedliterature for the pesticides commonly used in the irrigation areas of S-W NSW. It should be noted thatthe toxicity values vary depending on the species tested and the experimental conditions used (such aspH, temperature). For instance, the LC50 values for endosulfan vary from 0.1 µg/L for carp, up to740 µg/L for the water flea Daphnia magna. This wide range makes the selection of the indicator (ortest) species an important point to consider when developing a monitoring or ecotoxicology program.Also, data is not always available for species native to Australian rivers. However, overseas data,although not ideal, can still provide valuable information, and can be used as a guide for predicting thetoxicity of a pesticide to similar Australian species. However, a long term objective should be to gathersufficient toxicity data of Australian aquatic species.

Table 10 indicates that the insecticides most toxic to aquatic fauna are chlorpyrifos and endosulfanboth of which have LC50s of 0.1 µg/L or less. Other insecticides with low LC50s include malathion(0.6 µg/L), parathion (0.6 µg/L) and the pyrethroids deltamethrin (0.4 µg/L), fenvalerate (0.7µg/L) andlambda-cyhalothrin (0.3 µg/L).

Generally most herbicides tend to be less toxic to aquatic fauna (see Table 9) than insecticides,although there are exceptions, such as acrolein which is highly toxic to fish. Many herbicides,however, can be highly toxic to aquatic plants and algae (see Table 11). Atrazine for instance, inlaboratory mesocosms, killed 50% of Ribbonweed plants (Vallisneria americana) at a concentration of12 µg/L for 47 days (Correll and Wu 1982). Delistraty and Hershner (1984) found that 10 µg/Lreduced the growth of seagrass when exposed for 21 days and the net photosynthesis of several plantspecies was reduced after long exposure to 5-10 µg/L (Correll and Wu 1982). Herbicide toxicity toaquatic plants has the potential to alter the food webs and structure of aquatic ecosystems byeliminating the more sensitive plant species.

4.5 Bioaccumulation of pesticides.

Pesticides which slowly accumulate in organisms such as fish, may eventually cause chronic or acutetoxicity. Although a pesticide might only be present in trace quantities in the water, it can exert a largebiological effect if it is selectively taken up and accumulated in an organism's flesh.

The ability of a pesticide to bioconcentrate can be predicted from measurements of the octanol-waterpartition coefficient (Kow), since octanol has similar solvent properties to the tissue lipids in which thepesticides tend to accumulate. Typically, pesticides with a strong tendency to bioconcentrate, have highlog Kow values (> 4). A comprehensive list of log Kow values for pesticides has been compiled by Noble(1993).

For bioconcentration to occur, the pesticide must also be resistant to degradation and therefore have along half life. Organochlorine pesticides such as DDT and dieldrin have high Kow values as well aslong half lives. For this reason, they became a major problem in the 1960s and 1970s as theyaccumulated up the food chain, causing damage to the ecosystem and contaminating foodstuffs such asmeat, milk and fish. (Refer to the papers by Bevenue, 1976 and Olsen et al, 1993 for furtherinformation on the bioaccumulation of organochlorines)

Endosulfan, one of the few remaining organochlorines still in use, has a shorter half life and a lower Kow

value than most other organochlorines and hence does not tend to bioconcentrate to the same degree. Ithas however been detected in the flesh of native fish (Nowak, 1990).

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Table 9 Toxicity (LC50) of herbicides to aquatic faunaherbicides LC50

(ug/L)speciestested

time oftest (h)

reference

2,2-DPA 6,000 Water flea (Daphniamagna)

24 Frear and Boyd (1967)

105,000 Bluegill 96 Johnson and Finley (1980)2,4-D 1,400 rainbow trout 96 Johnson and Finley (1980)

1,850 Calanoid copepod 48 Kader et al (1976)5,100 Carp 96 Vardia and Durve (1981)

25,000 Water flea (Daphniamagna)

48 Alexander et al. (1985)

236,000 Water flea (Ceriodaphniadubia)

48 Oris et al (1991)

acrolein 14 fathead minnow 96 Holcombe et al (1987)16 rainbow trout 96 Holcombe et al (1987)33 bluegill 96 Holcombe et al (1987)57 water flea 48 Macek et al (1976a)

amitrole 215,000 Waterflea (daphniamagna)

24 Crosby & Tucker (1966)

243,000 rainbow trout 96 Tscheu-Schluter & Skibba (1986)1,000,000 bluegill 48 Hughes and Davis (1962)

atrazine 720 Midge (Chironomustentans)

48 Macek et al (1976b)

4,500 rainbow trout 96 Bathe et al (1975)6,900 Water flea (Daphnia

magna)48 Macek et al (1976b)

15,000 fathead minnow 96 Macek et al (1976b)bensulfuronmethyl

>150,000 rainbow trout 96 Boulton (1991)

bentazone 3,874,000 Mosquitofish (Gambusiaaffinis)

96 Leung et al (1983)

bromacil 75,000 rainbow trout 48 Worthing (1987)186,000 fathead minnow 96 Geiger et al (1988)

bromoxynil 11,500 fathead minnow 96 Brooke et al (1984)chlorsulfuron >250,000 rainbow trout 96 Worthing (1987)copper sulphate 800-7,300 bluegills 96 Boulton (1991)dicamba 3,900 Scud (Gammarus

lacustris)96 Sanders (1969)

28,000 rainbow trout 96 Johnson and Finley (1980)diclofop-methyl 250 rainbow trout 96 Johnson and Finley (1980)diquat 1,000 striped bass 48 Hughes (1973)

3,000 Water flea (Daphniamagna)

48 Bishop and Perry (1981)

41,000 Bluegill 96 Berry (1976)70,000 rainbow trout 48 Alabaster (1969)

diuron 160 scud (Gammarusfasciatus)

96 Johnson and Finley (1980)

500 striped bass 48 Hughes (1973)1,200 stonefly 96 Sanders & Cope (1968)5,900 bluegill 96 Macek et al (1969)

14,200 fathead minnow 96 Call et al (1987)fluazifop-p-butyl

1,400 rainbow trout 96 Worthing (1987)

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Table 9 continuedherbicides LC50

(ug/L)speciestested

time oftest (h)

reference

glyphosate 1,400 rainbow trout 96 Folmar et al (1979)(as the RoundupR 1,800 Bluegill 96 Folmar et al (1979)formulation) 3,100 Carp 96 Liong et al (1988)

30,000 Midge (Chironomusplumosus)

48 Folmar et al (1979)

haloxyfop-methyl 400 rainbow trout 96 Worthing (1987)ioxynil 350 harlequinfish 48 Alabaster (1969)linuron 6,426 tilapia 48 Shafiei and Costa (1990)MCPA 1,500 bluegill 48 Hughes and Davis (1964)

20,000 rainbow trout 48 Lysak and Marcinek (1972)metolachlor 2,000 rainbow trout 96 Worthing (1987)

5,000 Water flea (Ceriodaphniacf dubia)

24 CSIRO unpublished data

metsulfuron >150,000 rainbow trout 96 Worthing (1987)molinate 200 rainbow trout 96 Cope (1965)

320 bluegill 96 Johnson and Finley (1980)340 stonefly 96 Sanders and Cope (1968)

1,300 rainbow trout 96 Worthing (1987)29,000 carp 96 Mansour and Mohsen (1985)

oryzalin 190 Scud (Gammarusfasciatus)

96 Johnson and Finley (1980)

paraquat 15,000 European carp 24 Liong et al (1988)500 Leopard frog 96 Linder et al (1990)

pendimethalin 420 channel catfish 96 Worthing (1987)propanil 350 goldfish (Carassius

auratus)48 Nishiuchi & Hashimoto (1969)

420 carp 48 Nishiuchi & Hashimoto (1969)8,600 fathead minnow 96 Geiger et al (1986)

simazine 49,000 guppy (Poeciliareticulata)

96 Bathe et al (1973)

85,000 rainbow trout 48 Alabaster (1969)90,000 bluegills 96 Bathe et al (1973)

thiobencarb 790 rainbow trout 96 Finlayson and Fagella (1986)1,420 carp 96 Metelev and Brichko (1980)

trifluralin 41 rainbow trout 96 Johnson and Finley (1980)47 bluegill 96 Macek et al (1969)50 Cyclopoid copepod 48 Naqvi et al (1985)60 Alonella sp. 48 Naqvi et al. (1985)89 bluegills 96 Worthing (1987)

Note 1: All toxicity data is for acute toxicity - not chronic.Note 2: When obtaining data from the AQUIRE database, only those with a ‘1’ or ‘2’ rating (reliable data)

were selected; less reliable data with a rating of ‘3’ or ‘4’ were not used.

30

Table 10 Toxicity of insecticides and fungicides to aquatic faunainsecticides andfungicides

LC50(ug/L)

speciestested

timeof test(h)

reference

azinphos-methyl 1.5 stonefly 96 Sanders and Cope (1968)4.2 bluegill 96 Macek et al (1969)

Bacillusthuringiensis

non toxic

benomyl 6 channel catfish (Ictaluruspunctatus)

96 Palawski and Knowles (1986)

120 rainbow trout 96 Palawski and Knowles (1986)carbaryl 1.1 Water flea (Daphnia

magna)24 Gaaboub et al (1975)

5.6 stonefly 96 Sanders and Cope (1968)11.6 Water flea (Ceriodaphnia

dubia)48 Oris et al (1991)

860 rainbow trout 96 Phipps & Holcombe (1985)1,190 carp 96 Kaur & Dhawan (1993)

chlorpyrifos 0.07 Scud (Gammarus pulex) 96 Van Wijngaarden et al (1993)0.12 Water flea (Daphnia pulex) 72 Siefert (1987)0.16 mosquito (Culex pipiens) 24 Nelson & Evans (1973)0.3 mayfly 96 Van Wijngaarden et al (1993)7.1 rainbow trout 96 Macek et al (1969)59 carp 48 El-Refai et al (1976)

cypermethrin 2.0-2.8 rainbow trout Meister (1992)deltamethrin 0.4 rainbow trout 96 Smith et al (1986)

0.9 European carp 96 Mestres & Mestres (1992)5.0 Daphnia magna 48 Mestres & Mestres (1992)

dicofol 262 rainbow trout 48 Holcombe et al (1982)390 Daphnia magna 26 Frear & Boyd (1967)650 stonefly 96 Johnson and Finley (1980)

dimethoate 2.3 Mullet (Mugilidae) 96 Aboul-Ela and Khalil (1987)7.8 frog (Rana hexadactyla) 96 Khangarot et al (1985)43 stonefly 96 Johnson and Finley (1980)

830 Water flea (Daphniamagna)

48 Beusen and Neven (1989)

4650 carp 96 Kulshrestha and Arora (1986)dimethirimol 87,000 eel (Anguilla japonica) 48 Yokoyama et al (1988)dithianon 130 channel catfish (Ictalurus

punctatus)96 Johnson & Finley (1980)

165 fathead minnow 96 Johnson & Finley (1980)endosulfan 0.1 European Carp 96 Sunderam et al (1992)

0.1 Cyclopoid copepod 48 Naqvi & Hawkins (19890.17 Rainbow trout 96 Lemke (1981)0.2 Bony Bream 96 Sunderam et al (1992)0.2 Water flea (Alonella sp.) 48 Naqvi & Hawkins (1989)0.5 golden perch 96 Sunderam et al (1992)2.1 Tiger frog 24 Gopal et al (1981)

2.3-2.4 silver perch 96 Sunderam et al. (1992)6-12 Mosquito fish (Gambusia

affinis)24 Joshi. & Rege (1980)

158-740 Water flea (Daphniamagna)

48 Naqvi & Hawkins (1989)

fenvalerate 0.7 fathead minnow 96 Bradbury et al (1985)0.9 Bluegill 48 Dyer et al (1989)4.2 Midge 24 Ali and Mulla (1978)30 carp 48 Reddy and Bashamohideen (1989)

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Table 10 continuedinsecticides andfungicides

LC50(ug/L)

speciestested

time oftest (h)

reference

lambda-cyhalothrin

0.3 Water flea (Ceriodaphniadubia)

48 Mokry & Hoagland (1990)

1.0 Water flea (Daphnia magna) 48 Mokry & Hoagland (1990)malathion 0.59 frog (Rana hexadactyla) 96 Khangarot et al (1985)

1.1 stonefly 96 Sanders and Cope (1968)1.6 water flea (Daphnia magna) 48 Maas (1982)3.4 mosquitofish (Gambusia

affinis)48 Tietze et al (1991)

85 carp 96 Verma et al (1981)mancozeb 1,300 Water flea (Daphnia magna) 48 Van Leeuwen et al (1985)

1,850 rainbow trout 48 Hejduk & Svobodova (1980)24,000 carp 48 Hejduk & Svobodova (1980)

methidathion 9 bluegill 96 Johnson & Finley (1980)14 rainbow trout 96 Johnson & Finley (1980)16 mosquito 24 Magnin et al (1988)

methomyl 32 midge 48 Johnson & Finley (1980)220 Water flea (Daphnia

longispina)96 Aboul-Ela & Khalil (1987)

870 snail 96 Aboul-Ela & Khalil (1987)1,000 rainbow trout 96 Sanders et al (1983)

monocrotophos 34 Crayfish (Procambarusacutus)

34 Carter & Graves (1972)

5200 rainbow trout 96 Johnson & Finley (1980)parathion 0.62 water flea (Daphnia magna) 96 Spacie et al (1981)

1.5 stonefly (Claasseniasabulosa)

96 Sanders & Cope (1968)

2.8 stonefly (Acroneuriapacifica)

96 Jensen & Gaufin (1964)

48 mosquitofish (Gambusiaaffinis)

48 Culley & Ferguson (1969)

3,200 carp 48 Nishiuchi & Hashimoto (1969)sulphur non toxicterbufos 6.7-16.8 rainbow trout 96 Howe et al (1994)

4 bluegill 96 Worthing (1987)13.3 fathead minnow 96 Geiger et al (1990)

trichlorfon 5.3 stonefly 96 Woodward and Mauck (1980)17 caddisfly 24 Carlson (1966)20 rainbow trout 96 Howe et al (1994)22 stonefly 96 Sanders and Cope (1968)

260 bluegill 96 Cope (1965)700 rainbow trout 96 Sanders et al (1983)

Note 1: All toxicity data is for acute toxicity - not chronic.Note 2: When obtaining data from the AQUIRE database, only those with a ‘1’ or ‘2’ rating (reliable data)

were selected; less reliable data with a rating of ‘3’ or ‘4’ were not used.

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Table 11. Effect of herbicides on aquatic floraherbicides Conc.

(ug/L)species tested and effect time of

testreference

2,4-D 200-2000 change in growth of parrot’sfeather (Myriophyllumbrasiliense)

14 days Sutton and Bingham (1970)

190-260 mortality of Water-milfoil(Myriophyllum spicatum)

70 days Van et al (1986)

100 change in productivity ofgreen algae (Scenedesmusquadricauda)

6 days Stadnyk et al (1971)

amitrole 1680 EC50, change in biomass ofgreen algae (Selenastrumcapricornutum)

14 days Turbak et al (1986)

atrazine 12 50% of Vallisneriaamericana killed

47 days Correll and Wu (1982)

10 reduced growth of seagrass 21 days Delistraty and Hershner (1984)5-10 net photosynthesis of several

plant species reducedCorrell and Wu (1982)

20 change in biomass of algae 2 days DeNoyelles et al (1982)1-100 Change in biomass of Sago

pondweed (Potamogetonpectinatus)

28 days Fleming et al (1991)

diquat 110 mortality of Elodea sp. 30 days Berry (1976)110 mortality of Lemna minor 30 days Berry (1976)

diuron 100 change in productivity ofgreen algae (Scenedesmusquadricauda)

2 days Stadnyk et al (1971)

glyphosate 1-10000 change in biomass of sagopondweed (Potamogetonpectinatus)

28 days Fleming et al (1991)

100-10000 change in growth of sagopondweed (Potamogetonpectinatus)

14 days Hartman & Martin (1985)

paraquat 600-1000 mortality of sago pondweed(Potamogeton pectinatus)

26 days Fry et al (1973)

propanil 51-100 EC50, change inproductivity of algae

3 hours Tucker (1987)

simazine 660-790 EC50, change inproductivity of algae

7 days Goldsborough & Robinson(1988)

2.2 EC50, change inproductivity of green algae(Selenastrumcapricornutum)

1 day Turbak et al (1986)

thiobencarb 20-38 EC50, change in numbers ofgreen algae(Selenastrumcapricornutum)

3 days Kasai and Hatakeyama (1993)

trifluralin 1000 change in biomass of greenalgae

30 days Johnson (1986)

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4.6 An environmental risk ranking of pesticides.

There are a large number of different pesticides used in agriculture and it is important for watermanagers to be able to assess which of these chemicals pose the greatest threat to the environment. Aproper assessment would include a large number of parameters and requires very complex computermodels. There are also some less accurate but much simpler equations which have been proposed andthese can provide a useful ‘first pass’ assessment. One such equation is;

Environmental Risk = (M x t1/2) / (LC50 x Koc)

where;M = the rate of pesticide application in (kg/ha)t1/2 = pesticide half life (days)LC50 = lethal toxicity to the most sensitive fish species (µg/L)Koc - soil organic carbon sorption coefficient

(This equation is similar to one proposed by Peterson and Batley (1993) except that the Koc valuehas been used rather than the Kow value)

Another ‘first pass’ approach is used by Environment Australia (formerly the CommonwealthEnvironment Protection Agency) for the environmental risk assessment of pesticides in water bodies(Curnow et al. 1993), and was initially developed by the USEPA (Urban & Cook 1986). First, theestimated environmental concentration (EEC) is calculated for the worst case of direct overspray to a15cm depth of standing water, at the maximum label rate. Second, the EEC is divided by the LC50 forthe most sensitive organism to obtain a hazard index called Q. If Q is less than 0.1, it means that theenvironmental concentrations should be one tenth or less of the LC50 value and it is assumed thatadverse environmental effects are unlikely. This method has been applied to the pesticides commonlyused in the irrigation areas of S-W NSW and the results are presented in Table 12.

Table 12. Q values for pesticides used in the Riverina.Herbicide Q value insecticide,

fungicideQ Value

acrolein(1) 71 chlorpyrifos 9520trifluralin 18 endosulfan 4700molinate 12 carbaryl 606oryzalin 12 malathion 340diuron 9 deltamethrin 208propanil 7 parathion 1612,2-DPA 4.4 benomyl 110atrazine 2.9 dimethoate 93thiobencarb 2.6 fenvalerate 57copper 2.5 trichlorfon 50diclofop 2.1 terbufos 502,4-D 0.5 azinphos-methyl 43glyphosate 0.5 cypermethrin 33metolachlor 0.4 lambda-cyhalothrin 20MCPA 0.3 monocrotophos 7.8diquat 0.2 methidathion 7.4fluazifop-p-butyl 0.15 methomyl 7.1bromacil 0.03 dicofol 2.5simazine 0.03 mancozeb 0.8paraquat 0.02bensulfuron <0.001

(1) Acrolein is used at high concentration doses of 2-20mg/L for 1-8 hrs, or low concentration doses of 0.1-1.0mg/L for 48 hrs (Bowmer and Sainty 1991). The Q value was calculated assuming a concentration of 1.0 mg/Lfor 48 hrs.

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The Q values indicate that the pesticides which pose the highest environmental risk are endosulfan andchlorpyrifos. Other pesticides with high Q values include carbaryl, malathion, deltamethrin, parathion,benomyl and dimethoate. Most herbicides have relatively low Q values, although this is partly due tothe lack of LC50 data for aquatic plants (most toxicity data for plants are expressed as EC50s ratherthan LC50s). In the following paragraphs, each of the pesticides with high Q values, and any otherswhich are also considered to pose an environmental risk, are discussed in further detail.

ChlorpyrifosChlorpyrifos, an organophosphate, poses a high environmental risk (Q value of 9520), due to its veryhigh toxicity and widespread use (including aerial spraying of rice). In natural waters the half life ofchlorpyrifos is short (16 to 33 hours reported by Marshall & Roberts (1978)), although this is stronglydependent on pH and temperature. Chlorpyrifos is readily adsorbed onto sediment and hence organismsinhabiting the sediment-water interface will receive larger concentrations than free swimming organisms(USEPA 1986)

EndosulfanEndosulfan is an organochlorine and poses a high environmental risk (Q value of 4770), due to its veryhigh toxicity to both fish and aquatic invertebrates. It does not readily bioaccumulate in food chains(Peterson and Batley 1991b, USEPA 1980a), but has been detected in the flesh of native fish species(Nowak 1990). Although it readily degrades in water, it also binds strongly to sediment and can beslowly released back into the water producing low level concentrations for many months (Peterson &Batley 1991a). Endosulfan is used on a number of crops in S-W NSW including vegetables, soybeansand maize, and is often aerially applied. This pesticide has been responsible for a number of fish killsin the cotton growing districts of northern NSW (Bowmer et al. 1995).

CarbarylCarbaryl is a carbamate insecticide and is applied to a range of crops including grapes and somevegetables. It has a high Q value since it is very toxic to invertebrates such as water fleas (LC50 of 1.1µg/L) and stone flies (LC50 of 5.6 µg/L), however it has a much lower toxicity to fish (LC50 forrainbow trout is 860 µg/L). It has a very low oral and dermal toxicity to mammals and is therefore alsoused as a lawn and garden insecticide (Ware 1983) .

MalathionMalathion is an organophosphate insecticide which is toxic to a range of aquatic organisms. Largequantities are used as a rice seed dressing to control bloodworm attack on germinating rice. Malathionposes an environmental risk due to its high Q value and the large quantities used each season. It doeshowever degrade fairly rapidly in both soil and aquatic environments.

Pyrethroid insecticidesPyrethroid insecticides (such as cypermethrin, lambda-cyhalothrin, deltamethrin and fenvalerate) arevery hydrophobic with low solubility and large octanol-water coefficients (see Table 7). Thus it isexpected that material entering the water will rapidly leave it, by either degrading to non-toxiccompounds or binding to organic matter in sediments. Although pyrethroids, as a family of chemicals,are highly toxic to both aquatic invertebrates and fish, the environmental risk is minimised by theirrapid dissipation from water bodies.

ParathionParathion is an organophosphate which is highly toxic to aquatic invertebrates and fish. It is alsohighly toxic to birds (Mulla and Mian 1981) has caused their accidental poisoning (Smith 1987).However parathion is only used in small quantities in the irrigation areas of S-W NSW and hence therisk to the environment is limited.

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DicofolAlthough dicofol has a fairly low Q value of 2.5, it requires special mention since it is a metabolite ofDDT and trace amounts of DDD, DDE and DDT may be present as impurities (Barrett et al. 1991).For this reason it has been banned from use in the dried fruit industry of the Lower Murray region(Creecy, NSW Dept Agriculture, Griffith, pers. comm. 1994).

AtrazineAtrazine is a selective herbicide which is applied to the soil. Since it does not adsorb strongly to soilsand is also relatively persistent, atrazine tends to move within the aquatic environment, contaminatingboth surface and groundwater. Atrazine has been detected more widely in groundwater than any otherherbicide. Concentrations of atrazine up to 88 µg/L have been found in groundwater in the USA,although most detections have been below 10µg/L (Ritter 1990). In Ontario, Canada, a survey ofdrinking water wells, found that 95% of them were contaminated with atrazine or its metabolite.(Hallberg 1989). Atrazine has been measured at concentrations from 0.2 to 1.4 µg/L in almost allsurface waters examined in a survey of agricultural regions of eastern England (Croll 1986, 1991).There are numerous other reports of atrazine contamination of both groundwater and surface water,including 18 lakes in Switzerland (Buser 1990), drinking water in Germany (Iwan 1988), groundwaterin Germany (Kuhnt & Franzle 1993, Skark & Zulleiseibert 1995), drinking water in California (Lam etal. 1994), and rivers in Austria (Chovanec & Winkler 1994). A study in an agricultural region of theUSA detected several herbicides and insecticides in rainfall, including atrazine at concentrations up to2.19 µg/L (Richards et al 1987). Similar observations have been made in Germany (Bester et al.1995)

In Australia, there have been a number of studies which have detected atrazine in surface orgroundwaters. Atrazine or simazine was detected in 50% of observation wells in the irrigation areasnear Shepparton, Victoria (Bauld et al 1992), while in the irrigation areas and pine plantations ofsouth-east South Australia it was detected in groundwater at four of the eight sites tested, withconcentrations ranging from <0.02 µg/L to 2.00 µg/L (Stadter et al, 1992). In Tasmania atrazine hasbeen detected in streams which have commercial forestry operations within the catchment (Davies et al.1994).

Although atrazine has a Q value which is much lower than many other pesticides (see Table 12), itposes an environmental risk due to its persistence and mobility in both surface and groundwaters, and itcould have a large impact on aquatic plants (Table 11).

DiuronDiuron is a herbicide widely used in the MIA for weed control in horticulture, particularly citrus. Itcan persist in the soil for many months and may persist into the next growing season. Diuron is alsoused in winter as a soil residual herbicide in irrigation channels, and the first flow of the season must bediverted due to trace levels still being present. Boulton (1991) reported that in the Deniliquin area therehave been problems in private irrigation schemes associated with misuse of diuron in drainage channels,with the resultant death of a significant number (over 100) of eucalypt trees.

Although the Q value for diuron is only 9, it poses an environmental risk due to its persistence in soil,in some cases for over one year.

MolinateAlthough molinate is only used on rice, the total quantities applied each season (>100,000 kg in theMIA alone) far exceed any other herbicide. It is detected in most irrigation drains during October-December when it is being applied to rice fields, and the concentrations often exceed the guidelines bothfor drinking water and for the protection of the aquatic ecosystem. Concentrations of over 100 µg/L(which is 40 times higher than the interim water quality guideline for ecosystem protection) have beenrecorded in drainage water from rice farm catchments (see Figures 6 and 12 in Chapter 7).

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AcroleinAcrolein is only registered for use in NSW by the Irrigation Boards, and specifically for the control ofsubmerged weeds in irrigation supply channels. It is highly toxic to fish and care must be taken not tocontaminate natural waterways. It does however dissipate rapidly from water leaving no phytotoxicresidues (Bowmer 1987) and based on its chemical properties bioaccumulation is not expected(Bowmer, pers. comm.).

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5. WATER QUALITY GUIDELINES FOR PESTICIDES.

5.1 Australian Water Quality Guidelines developed by ANZECC

The Australian Water Quality Guidelines were developed in 1992 by the Australian and New ZealandEnvironment & Conservation Council (ANZECC) as part of a national water quality managementstrategy that seeks to manage the nation’s water resources on a sustainable basis.

When developing guidelines for the whole nation, it was acknowledged that not all waterbodies wouldhave the same set of environmental values. This depends on the different uses and values that acommunity might have (eg agricultural water, swimming, fishing, protection of the ecosystem), and alsodepends on the existing condition of the waterbody. For instance, a pristine mountain stream mighthave different values and uses to those of drainage water in an irrigation channel.

Therefore, different guidelines were developed for five major uses or values of water. These were:

• protection of the aquatic ecosystem• drinking water supply• recreation and aesthetics• agricultural water• industrial water

Generally, the water quality guidelines for the ‘protection of aquatic ecosystems’ are the most stringentand most difficult to meet. For example, the pesticide chlorpyrifos has a guideline value of 2 µg/L for‘drinking water supply’, and a guideline for the ‘protection of the aquatic ecosystem’ of 0.001 µg/L, i.e.over a thousand times lower.

In terms of toxic chemicals such as pesticides, the guidelines that are most relevant to water quality inthe irrigation areas of S-W NSW are: ecosystem protection and drinking water supply. The quality ofthe water in two of the remaining three categories i.e. recreation and aesthetics and industrial watershould be similar to the guidelines for drinking water supply if human contact or consumption is likely.

The remaining environmental value i.e. agricultural water is further divided into the following threeintended uses: i) irrigation, ii) livestock and iii) farmstead water supply. Again, the ANZECCguidelines recommend that whenever human or animal contact or consumption is likely, the drinkingwater guidelines should apply. While this would be accepted by most as valid reasoning in terms ofwater for farmstead use, it may be argued that defaulting to the values for drinking water supply is overprotective with respect to livestock. However, ANZECC point out that “the recommendation thatdrinking water guidelines be adopted for maximum limits of pesticides in drinking water for livestockshould provide a margin of safety for livestock and prevent unacceptable pesticide residues in animalproducts” (ANZECC, 1992).

For irrigation use, the ANZECC guidelines suggest that herbicides are the most important compoundsas “these may enter irrigation water through treatment to control algae and submerged aquaticweeds or treatment of irrigation channels and ditches to control terrestrial weeds” (ANZECC, 1992).The guidelines recommend the maximum concentration of herbicides in irrigation water and an estimateof their hazard to crops resulting from residues in water. Of the 30 compounds listed only 4 have aspecific guideline limit: acrolein, 0.01 mg/L; amitrole 0.002 mg/L; diuron, 0.002 mg/L and 2,2-DPA,0.004 mg/L. The remaining herbicides are covered by a blanket limit of 0.1 mg/L. However, 22compounds are rated as having either a moderate or high potential of being hazardous to crops. Themajor concern regarding insecticides, is not because of crop damage but rather the effect of insecticidesin irrigation water or soil runoff water and the possible impact on aquatic ecosystems.

38

Drinking water guidelines are usually derived from toxicological data extrapolated from exposure ofersatz-human test animals (e.g. rats, mice etc.) to large doses of particular chemicals. On the otherhand, ecosystem protection guidelines are generally derived from ecotoxicological data resulting fromexposure of the most sensitive animals or plants of an ecosystem to a particular chemical.

When developing the ANZECC guidelines, an attempt was made to provide guidance on the range ofconcentrations or levels of each key indicator required to provide adequate protection of theenvironmental value, and it is important that these guidelines are not considered as blanket values fornational water quality. There are a wide range of ecosystem types throughout Australia, and to assumethat one set of specific values could apply equally to all would be ill advised. Local site specificinformation will be needed to supplement the broad information provided in the ANZECC guidelines,particularly for ecosystem protection.

Table 13 shows the ANZECC water quality guidelines for pesticides which were developed for the‘protection of aquatic ecosystems’. For the irrigation areas in south-west NSW, interim guidelines forsome common pesticides which were not included in the 1992 ANZECC guidelines, were developed bythe NSW EPA.

Table 13 Water quality guidelines for the protection of freshwater ecosystems.Guidelines (µg/L) Guidelines (µg/L)

Pesticide ANZECC NSW EPAInterim

Pesticide ANZECC NSW EPAInterim

aldrin 0.010 parathion 0.004chlordane 0.004 acrolein 0.200DDE 0.014 diazinon 0.00006DDT 0.001 atrazine 2dieldrin 0.002 bromacil 100endosulfan 0.010 0.010 bensulfuron-methyl 100endrin 0.003 2,4-D 4heptachlor 0.010 diuron 8lindane 0.003 glyphosate 65methoxychlor 0.040 MCPA 232mirex 0.001 metolachlor 8toxaphene 0.008 molinate 2.5chlorpyrifos 0.001 0.001 simazine 10demeton-s-methyl 0.100 thiobencarb 1azinphos-methyl 0.010 trifluralin 0.10malathion 0.070 terbufos 0.004

5.2 Drinking Water Quality Guidelines developed byNHMRC/ARMCANZ

Although the 1992 ANZECC guidelines included values for ‘drinking water supply’, a more up-to-dateand comprehensive set of guidelines for drinking water have been developed jointly by NHMRC(National Health & Medical Research Council) and ARMCANZ (Agriculture & ResourceManagement Council of Australia and New Zealand) in 1996, and are based on guidelines specified bythe World Health Organisation (WHO).

For pesticides, the drinking water guidelines were set at the concentration that does not result in anyrisk to the health of the consumer over a lifetime. The risk may be due to direct toxicity, or because the

39

chemical can cause (or is suspected of causing) cancer. The guideline values are very conservative,include a range of safety factors, and always err on the side of safety.

The guideline values are divided into two categories:

i) Health Risks: Water containing the pesticide at this level could be safely consumed over alifetime without adverse effects. The values are based on 10 % of the Acceptable Daily Intake (ADI)(as determined by the NHMRC Pesticide and Agricultural Chemicals Standing Committee)

ii) Limit of Determination: Pesticides should not be present in drinking water. Inpractical terms, this means that they should not exceed the limit of determination (the level atwhich the pesticide can be reliably detected using practicable and widely available methods). Ifpesticide contamination exceeds the level of determination, remedial action should be taken todetermine the source and if possible to stop further contamination. Exceeding the limit ofdetermination indicates that contamination of drinking water has occurred; it does notnecessarily indicate a hazard to public health.

Table 14 shows the drinking water guidelines with respect to pesticides developed both by ANZECC(1992) and NHMRC/ARMCANZ (1996). It should be noted that although a large number ofchemicals have been listed, many of these are unlikely to be found in Australian drinking watersupplies.

5.3 Other points to consider

a) The effect of variations in natural water quality parametersMost pesticides currently used in Australia are chemicals which do not occur in the naturalenvironment. They were specifically designed as biocides for agricultural, urban or industrial uses andwhich, if allowed to move into the general environment, continue to act as biocides to non targetorganisms. Factors which can influence the toxicity of these compounds in "real" systems includefluctuations in water quality, with respect to natural physico-chemical parameters. Variations in theseparameters can increase or decrease the toxicity of pesticides in natural environments makingextrapolation of laboratory derived toxicity data to the field difficult. The incorporation of safetyfactors into the development of water quality guidelines is designed to act as a safeguard against thesevariations in toxicity that might occur in natural waters.

b) Applying Water Quality Guidelines to irrigation drainage channelsDrainage waters from irrigated agriculture frequently contain mixtures of pesticides which may enternatural waterbodies directly or via a system of drainage channels. Most of these channels have beenbuilt specifically for receiving drainage water and are not natural. The question then arises as towhether the water quality in these drainage channels should have to meet the same set of stringentguidelines as the natural watercourses in the region (i.e. the guidelines for ecosystem protection) orwhether a more lenient set of guidelines is acceptable.

Issues that need to be considered when determining suitable water quality guidelines for drainagechannels are;• Is the drainage water being re-used downstream, and if so is it being used as drinking water for

stock or for human consumption. If it is, then the water quality should at least satisfy the drinkingwater guidelines.

40

Table 14 Australian Drinking Water Guidelines for Pesticides.ANZECC NHMRC ANZECC NHMRC

Pesticide WQG(µg/L)

WQG(µg/L)

LOD(µg/L)

Pesticide WQG(µg/L)

WQG(µg/L)

LOD(µg/L)

acephate 20 10 heptachlor (including itsepoxide)

3 0.3 0.05

alachlor 3 hexaflurate 60 30aldicarb 1 1 hexazinone 600 300 2aldrin (and dieldrin) 1 0.3 0.01 lindane 10 20 0.05ametryn 50 5 maldison (malathion) 100 50amitrole 1 10 1 methidathion 60 30asulam 100 50 methiocarb 5 5atrazine 20 0.5 methomyl 60 30 5azinphos-methyl 10 3 2 methoxychlor 300 0.2barban 300 metolachlor 800 300 2benomyl 200 100 metribuzin 5 50 1bentazone 400 30 metsulfuron-methyl 30bioresmethrin 60 100 mevinphos 6 5 5bromacil 600 300 10 molinate 1 5 0.5bromophos-ethyl 20 10 monocrotofos 2 1bromoxynil 30 30 nabam 30carbaryl 60 30 5 napropamide 1000 1carbendazim 200 100 nitralin 1000 500carbofuran 20 10 5 norflurazon 50 2carbophenothion 1 0.5 omethoate 0.4carboxin 300 2 oryzalin 60 300chlordane 6 1 0.01 oxamyl 100 5chlordimeform 20 paraquat 40 30 1chlorphenvinphos 10 5 parathion 30 10chlorothalonil 30 0.10 parathion-methyl 6 100 0.3chloroxuron 30 10 pebulate 30 0.5chlorpyrifos 2 10 pendimethalin 600 300chlorsulfuron 100 perfluidone 20clopyralid 1000 1000 1000 pentachlorophenol 10 0.01cyhexatin 200 permethrin 300 100 12,4-D 100 30 0.10 picloram 30 300DDT 3 20 0.06 piperonyl butoxide 200 100demeton 30 pirimicarb 100 5diazinon 10 3 1 pirimiphos-ethyl 1 0.5dicamba 300 100 pirimiphos-methyl 60 50dichlobenil 20 10 profenofos 0.6 0.33,6-dichloropicolinic acid 1000 promecarb 60 30dichlorvos 20 1 1 propachlor 50 1diclofop-methyl 3 5 propanil 1000 500 0.1dicofol 100 3 propargite 1000 50dieldrin (see aldrin) 1 0.3 0.01 propazine 50 0.5difenzoquat 200 100 propiconazole 100 0.1dimethoate 100 50 propoxur 1000diphenamid 300 2 propyzamide 300 2diquat 10 5 0.5 pyrazophos 1000 30disulfoton 6 3 1 quintozene 6 30diuron 40 30 simazine 20 0.5DPA (2,2-DPA) 500 500 sulprofos 20 10EDB 1 1 silvex (see fenoprop)endosulfan 40 30 0.05 2,4,5-T 2 100 0.05endothal 600 100 10 temephos 20 300 300endrin 1 terbacil 30 10EPTC 60 30 1 terbufos 0.5 0.5ethion 6 3 terbutryn 300 1ethoprophos 1 1 1 tetrachlorvinphos 100 2etridiazole 100 0.1 thiobencarb 40 30fenamiphos 0.3 thiometon 20 3fenarimol 30 1 thiophanate 100 5fenchlorphos 60 30 thiram 30 3fenitrothion 20 10 triadimefon 100 2fenoprop 20 10 trichlorfon 10 5fensulfothion 20 10 10 trichlorpyr 20 10fenvalerate 40 50 trifluralin 500 50 0.1flamprop-methyl 6 3 vernolate 30 0.5fluometuron 100 50formothion 100 50fosamine ammonium 3000 30glyphosate 200 1000 10

note: LOD = limit of determination

41

• Does the drainage water pass directly into a naturally occurring permanent waterbody such as theMurrumbidgee or Murray River, or is it re-used on downstream farms. If it is re-used beforeentering natural waterbodies, less stringent water quality guidelines might be acceptable.

• Is the receiving channel a naturally occurring ephemeral creek that has been converted into apermanent water body by the large volumes of drainage water (examples are Mirrool Creek, YancoCreek and Coleambally Creek)? If so, should these water bodies be regarded as ‘natural’ systemsand therefore have to meet the same water quality guidelines as other natural watercourses in theregion? This issue might need to be determined on a case by case basis.

• All drainage channels are inhabited (or used) by a range of plant and animal species, including alarge number of water birds. It is important to ensure that the water quality in drainage channels(whether they are ‘natural’ or ‘artificial’) is sufficiently high to ensure the protection of thesespecies.

Water Quality Guidelines for both the ‘natural’ and ‘artificial’ water bodies in these regions need to bedetermined by the community, using the National Guidelines as a basis. It is likely that differentguidelines might be applied to each waterbody depending on the environmental values of each system.The guidelines will also need to be reviewed on a regular basis as further knowledge about the aquaticecosystems and the impact of pollutants such as pesticides, becomes available.

c) Pesticides: concentration vs loadWater quality guidelines are based on concentration rather than total load since individual organismsrespond to the concentration of a toxin. However, exposure over time may also be important at boththe individual organism and ecosystem level. Constant exposure to low levels of pesticides, which areboth hydrophobic and persistent, may lead to bioaccumulation in individual organisms andbioconcentration within the food web of the ecosystem. The pesticide loading of an ecosystem,particularly a closed system, or the loading of ‘sinks’ within the system (e.g. sediment accumulationareas), may be critical in determining the long term viability of the ecosystem. The resulting ecosystemimpact will depend on the toxicity of the pesticides, their degradation rates, bioavailability and thevectors in which they reside. Constant loading of a system with respect to pesticides could result in adrift in ecosystem population because more resistant species are favoured.

Therefore, there might be instances where not only pesticide concentration, but also the total pesticideload entering the system will need to be considered.

42

6. MONITORING AND SAMPLING OF PESTICIDES

6.1 Sources of pesticide contamination in drainage waters

When monitoring pesticides in drainage water from irrigated agriculture, the sampling frequencyrequired to obtain a true reflection of fluctuations in water quality depends on;

• the timing of application of these chemicals to crops,• the irrigation regimes used and,• the weather conditions during or following application.

Furthermore, the distance a monitoring point is away from the catchment, changes the travel time, theduration and the height (maximum concentration) of a pesticide pulse. Increasing the catchment areabeing monitored results in a greater opportunity for dilution of drainage water while at the same time,depending on the farming practices in the catchment, it also increases the possibility of a greaternumber of different pesticides reaching the monitoring point.

The possibility of pesticides leaving the targeted field depends on many factors including;

• the type and amount of chemical applied (which in turn depends on the crop being grown),• the water management regimes being used.

In the irrigation areas of S-W NSW there are three main crop / water management regimes.

Surface Drainage (Irrigated Row Crops)These include permanent horticultural crops (e.g. grapes, citrus) and annual row crops (e.g. maize, soybeans). The highest pesticide concentrations tend to occur at the start of the first irrigation eventfollowing pesticide application. With furrow irrigation a series of pesticide spikes may be evident(when water from individual furrows reach the drain) the severity of which diminishes towards the endof the irrigation. Concentrations of pesticides in drainage water from subsequent irrigations are lowerunless a fresh application of the chemical occurred in the interim.

Subsurface Drainage (Irrigated Row Crops)This includes horticulture (e.g. grapes, citrus) which is tile drained and row crops (e.g. maize, soybeans) which have “mole” drains to remove subsurface water. Similar patterns of pesticide pulses willappear in drainage water from both the tile and mole drains as irrigation water percolates through thesoil to the sub-surface drains. However, the pesticide composition of tile drainage water may beinfluenced by encroaching groundwater which, depending on sump pump timing, may act as a diluent.Pesticide composition in sub-surface drains will be different to surface drainage since some pesticideswill be selectively removed by adsorption to soil particles before reaching a subsurface drain. There isalso likely to be a greater lag time between the initiation of an irrigation event and the appearance ofleached pesticides in tile subsurface drains as compared to surface drainage.

Flood Irrigated Rice FarmingIn rice farming, pulses of pesticides may be detected shortly after chemical application even though,theoretically, the rice floodwater is contained in bays. These pulses may be due to:i) aerial overspray events,ii) seepage / leakage of rice floodwater through the walls of the rice bays,iii) rain events, when the rainfall exceeds the water free volume of the rice bay,

43

iv) wind events, wave action can cause floodwater to both overtop bay walls and, due tocontinuous wave action, breach walls resulting in loss of rice floodwater and associatedchemicals (Korth et al., 1995a),

v) deliberate release of rice bay floodwater by farmers (e.g. by siphoning or breaking bay walls)to control algal slime problems.

6.2 Sampling Techniques

The most frequently used sampling regime employed to monitor waterbodies for pesticides involves thecollection of manual “grab” samples. Generally, a bottle or bucket is lowered into the surface waterand filled, and the sample is transferred to a cooled container for transport and storage prior to analysis.Several days may elapse before final testing is completed.

When developing a sampling protocol the following shortcomings should be kept in mind:

• the frequency of sample collection may not always be matched to the frequency of events occurringin the catchment

• surface water may be inappropriate for sampling as water may be temperature stratified, or in abackwater, or may be biased from an aerial overspray

• sampling vessels may be inappropriate, eg. plastic may adsorb pesticides and compromise sampleintegrity

• transport to the laboratory may be inappropriate eg. exposure to sunlight and ambient temperaturescan lead to degradation of various pesticides

• the longer the holding time prior to analysis the greater the opportunity for pesticide degradation.

Sampling locationGenerally, for flowing water bodies, samples should be taken at the point of maximum mixing which isusually the point of greatest flow and at ~ 1/3 water depth. To sample at this point it may be necessaryto use a corked bottle, or a Niskin/Nansen type bottle on a cable fitted with messengers, to take thesample. The sampling point should be well downstream of any tributary input to ensure adequatemixing has occurred (a good rule of thumb is to sample at a distance at least 48 channel widthsdownstream of the input (O’Loughlin, 1975). The sampling method should be consistent for everysample collected. Local conditions are extremely important and need to be considered when developingthe monitoring protocol and determining the location of sampling points. However, pre-judging theexpected sample composition may prejudice the choice of monitoring strategy and could result insignificant events being missed. This problem may be minimised by continuous or frequent sampling(possibly using an autosampler).

Sample preservationSample containers should be made of dark coloured glass, or covered clear glass, to minimise exposureof the sample to sunlight and the bottles should be ice cooled during transport and storage. If long termtransport and/or storage is anticipated, and freezing is not an option, a preservative such as mercuricchloride (~ 40 mg/L) may be added to prevent microbial degradation of pesticides. For some pesticidesit is more important to control pH by buffering the samples as significant losses of the compound mayoccur due to hydrolysis. For example, the half life of chlorpyrifos at pH 7 is ~ 100 days whereas it isonly ~ 1.5 days at pH 8. On-site extraction of pesticides into a solvent or onto a solid phase or on-sitetesting of the water using ELISA kits or biosensors may be mechanisms by which problems regardingsample stability can be overcome. Generally, despite sample preservation, the length of sample storagetime prior to analysis or extraction should be minimised (note: most pesticides, once in a solvent, arestable for at least 6 months).

44

Automatic SamplersWhile manual methods are commonly used to sample water for pesticide analysis, automatic samplersoffer considerably more scope, particularly for sites that may be remote or when human resources arelimited. Automatic samplers can be set to take a series of discrete samples and/or a composite sample(taken as a continuous sample or a series of individual samples which are pooled) over a fixed period oftime (usually 24 h). Sampling frequency and mode can easily be adjusted to a predetermined regime tomaximise return of information and minimise sampling effort. Composite samples will return theaverage pesticide concentrations seen over a given time period. Automatic samplers set to take discretesamples, can be adjusted to take fixed sample volumes at predetermined time intervals. Each discretesample provides a snapshot of sample composition at a particular point in time. The number of discretesamples taken depends on the volume collected (usually 500 or 1000 mL) at each time interval and thephysical size of the automatic sampler. While fixed time intervals for discrete sampling can be set tosuit a particular monitoring regime, short term fluctuations in sample composition occurring betweensample collections may still be missed. These problems may be minimised by using automatic samplerswhich offer advanced programming facilities and the ability to collect a combination of composite anddiscrete samples. Event triggered sampling accessories are available which are particularly useful formeasuring stormwater or irrigation events as they can be set to increase sampling frequency in responseto increasing discharge volumes. Problems regarding analyte stability resulting from holding samplesin the autosampler for long periods between sample collection and preparation may be minimised byhaving refrigerated or cooled sampling chambers, adding preservatives or buffers to the samplecontainers, or (under certain circumstances) by placing solvents or sorbents either in the samplingcontainers or between the pump and the containers. Transport of samples back to the laboratory maythen only be necessary at infrequent intervals depending on the battery life of the sampler and/or theavailability of power.

Automatic samplers have some drawbacks such as the possibility of breakdowns, the necessity forperiodic maintenance and the likelihood of damage caused by vandalism or exposure to severe stormevents. The length and type of material used for the sample tubing is also important and can influencethe integrity of the sample due to adsorption of pesticides onto the walls of the sample tube. Use ofmaterials such as glass and/or teflon should be maximised to reduce the possibility of analyte loss dueto adsorptive processes. The positioning of the sample inlet in a water body is as critical for automaticsampling as it is for manual sampling. However, because the inlet position is usually at a fixed point itmay be difficult to correct for fluctuations in water height resulting from rising and falling water levels.Float controlled foot valves may be a mechanism by which these problems could be overcome.

6.3 Sampling Frequency

Sampling frequency is a major consideration when establishing a sampling protocol for the detection ofpesticides in waters. Hourly, daily, weekly or monthly regimes give progressively weaker informationabout pulses of pesticides entering water bodies. Sampling too infrequently could result in pesticidepulses being sampled at their maximum concentration or missed entirely or sampled somewhere inbetween. While the analytical costs resulting from a frequent sampling regime are high, it is wise tosample intensively, at least on one occasion during the initial periods following pesticide application, todetermine the minimum sampling frequency necessary to provide a true representation of pesticidelevels. For example, Figure 3 shows the molinate concentrations detected at Mirrool Creek daily,compared to the data that would have been obtained if sampled every 8 or 28 days. Clearly, most ofthe original information would be missed by moving to a 28 day sampling regime whereas some wouldbe retained by moving to an 8 day regime.

45

0

5

10

15

20

25

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57

days

ug

/L1 day

8 days

28 days

Figure 3: Concentration of molinate detected at Mirrool Creek when sampled dailycompared to the data obtained if sampled every 8 or 28 days (Korth et al., 1995a).

To maximise monitoring efficiency, sampling frequencies may need to be tailored to suit specificsituations eg. seasonal cropping regimes, irrigation regimes, stormwater events, overspray events orworst case scenarios. Drainage water from irrigated agriculture in the MIA and CIA was found tofluctuate continuously in terms of pesticide concentration during an irrigation season. For example,chlorpyrifos and malathion were detected in short (one or two day) pulses while molinate, endosulfanand diuron were present for most of the monitoring period. Under those circumstances, a monitoringregime based on the use of autosamplers for the collection of composite samples every 2 to 8 days (andsubsampling every 2 to 4 hours) was determined to be the minimum required to obtain a reasonablyaccurate reflection of drainage water pesticide contamination (Korth et al., 1995a).

6.4 Assessment Techniques

Techniques based on analytical chemistry have been the basis of most water quality monitoringprotocols with respect to the assessment of pesticide contamination until recently. Biologicaltechniques to assess water quality are assuming greater importance in recognition of the fact that theenvironmental quality of water is best recognised by the organisms that inhabit it (ie. aquatic biotareflect water quality). In reality, a combination of both techniques would be required to fully assess theimpact of pesticides on the aquatic environment and to identify the likely cause. Both the chemical andbiological techniques are discussed in further detail below.

6.4.1 Chemical Assessment TechniquesChemical assessment of pesticides usually requires isolation and concentration of the pesticide bysolvent partitioning or solid phase extraction followed by a sample cleanup procedure (eg. by columnchromatography) and identification and quantification by spectrophotometry, electrochemicaltechniques, gas chromatography (GC) and/or high performance liquid chromatography (HPLC). Anumber of techniques are available for both extraction and analysis of pesticides (US EPA, 1983;AOAC, 1990; DFG 1987 and 1992). The NSW EPA has recently published a range of methods for

46

sampling and analysis in water quality investigations (NSWEPA 1995a). The techniques most oftenused in the CSIRO Griffith Laboratory to analyse pesticides in water, involve liquid-liquid extraction -gas chromatography - mass spectrometry (LLE/GC/MS) and solid phase extraction - high performanceliquid chromatography (SPE/HPLC). A list of compounds (and their detection limits) included in theLLE/GC/MS pesticide scan is given in Table 15.

Table 15: Compounds included in the GC-MS scan and their limits of reporting (LOR) at the CSIROGriffith laboratoryCompound Limit of Reporting

(µg/L)Compound Limit of Reporting

(µg/L)diuron * 0.05 metolachlor 0.05molinate 0.05 chlorpyrifos 0.01methomyl qualitative only methidathion qualitative only#

trifluralin 0.05 α-endosulfan 0.01monocrotophos qualitative only profenofos qualitative onlysimazine qualitative only fluazifop-p-butyl qualitative onlyatrazine 0.05 β-endosulfan 0.01terbufos qualitative only endosulfan sulfate 0.01diazinon qualitative only lambda cyhalothrin qualitative onlypropanil qualitative only cypermethrin 0.05bromacil 0.50 deltamethrin qualitative onlythiobencarb 0.05malathion 0.01* For diuron, quantification is based on the thermal breakdown product, as the compound degrades in the GC

injection port# Compounds not quantified, only presence or absence indicated

It should be noted that water samples are generally solvent extracted as received (ie without separationof suspended particulate matter from the water column) and therefore represent a total rather thandissolved pesticide determination. For hydrophobic pesticides (Log KOW > 4) the resultantconcentrations may be an overestimate of the water column pesticide concentration as the compoundsare adsorbed to suspended solids or sediment particles. To determine the bioavailability of thesecompounds biological techniques (eg. ecotoxicology) are required (see below). Adsorptive processesare important and need to be considered when assessing the potential hazard of the chemicals over time.The stability of adsorbed pesticides is often enhanced and the compounds may become available at alater date due to resuspension of the bottom sediment or changes in the redox environment at thesediment-water interface.

6.4.2 Immunoassay TechniquesEnzyme Linked Immunosorbent Assay (ELISA) is a form of bioassay which relies on the formation ofantibodies to a pesticide antigen in mammalian blood (usually a rabbit). The antibody, raised by therabbit’s immune system in response to an injection of a pesticide antigen, reacts or recognises the threedimensional shape of the same pesticide molecule, if present in the sample. The antibodies are usuallyspecific to individual pesticides or to a particular group of pesticides with the same three dimensionalshape. The method involves competition for antibody binding sites between the pesticide in the sampleand a pesticide enzyme conjugate added to the tubes or microwells containing antibodies. Thecompetition for binding sites is concentration dependant. Once equilibration is reached the sample isrinsed from the tubes or microwells and two other substances are added to produce a coloured endpoint. The colour formed is inversely proportional to the log concentration of the pesticide in thesample. A typical calibration curve (microwells only) is sigmoidal in shape and the linear portion of thecurve is used to determine the concentration of the analyte. For a detailed review of the ELISA withrespect to pesticide analysis see Hock (1993).

47

The advantages of this technique are:

• Pesticides can be detected at low (ppb) levels directly in the sample water without preconcentration.Such levels are often close to water quality guideline levels.

• Relatively low cost, typically $20 - $30 per test.• Can be carried out in the field semi quantitatively.• Relatively simple test to perform.• Will target a specific pesticide.• Sample matrix effects (turbidity, salinity) are minor.

Some disadvantages are:

• Need for several different kits to screen mixtures of compounds.• Some cross reactivity of pesticides with similar three dimensional shapes can occur e.g. diuron

antigen cross reacts with linuron by 30%.

Two types of kits are available:

i) microplate kits which require laboratory facilities and a microplate reader. This method isquantitative and several test samples can be completed within 1.5 h and

ii) field kits or tube kits which can be used on site to assess the concentration of pesticides visuallyor with a field photometer. The test is semi-quantitative giving a result which is above orbelow a standard of known concentration and above zero calibrator.

Kits have been commercially available for some time e.g. triazines, aldicarb, 2,4-D, benomyl, alachlorand cyclodienes (Envirogard, Millipore Australia ). Currently in Australia, kits are being developed totarget specific pesticides by Dr John Skerritt and associates at the CSIRO Division of Plant Industry incollaboration with the University of California, Davis. Kits that are expected to be commerciallyavailable in the near future are for endosulfan, chlorpyrifos, molinate and diuron. Other kits beingdeveloped include bromacil, thiobencarb and bensulfuron.

The CSIRO Division of Water Resources worked in collaboration with Dr Skerritt's group to fieldvalidate some of these kits. For example, using the microplate kit for diuron water samples from 21 tiledrains in the Griffith area were tested in August 1994. The samples were tested using the ELISAmicroplate and also HPLC (with preconcentration) and GC/MS (solvent extracted). Figure 4 shows thelinear relationship between these techniques and the ELISA. The linearity is good (r = 0.91 for HPLCand r = 0.94 for GC). The fit is very good at the lower end of the range but as HPLC could not detectbelow 0.2µg/L the HPLC values fall out at this point. The ELISA limit of detection (LOD) is0.02µg/L and the GC/MS is 0.05 µg/L.

Similar testing has been carried out for chlorpyrifos and molinate microplate kits. The semi-quantitative field 'tube' kits have also been tested for molinate and chlorpyrifos. Table 16 shows theresult of >100 test samples from rice drainage at Willbriggie in Oct/Nov 1993. It can be seen that 85-90% of the samples that were positive using GC/MS were found to be positive, and in the correctconcentration range using the tube kits. This test has considerable application for water qualityofficers, environmental agency officers and farmers concerned with the quality of water.

Table 16: Comparison of molinate field tube kits and GC/MS for 114 samples from Willbriggie, NSW1992.

Concentration Range (µg/L) % match to0 - < 5 5 - 50 > 50 GC-MS

GC-MS 49 40 25 NAField (visual) 41 35 18 85

Field (photometer) 39 40 19 88

48

0

0.2

0.4

0.6

0.8

1

1.2

0 0.2 0.4 0.6 0.8 1 1.2

ELISA (ug/L)

HP

LC

or

GC

-MS

(u

g/L

)

HPLC

GC-MS

Figure 4: Comparison of ELISA and GC-MS or HPLC for the determinationof diuron in sub-surface tile drainage water.

6.4.3 Biological Assessment TechniquesThese techniques involve the assessment of biota in the water, relying on the organisms’ sensitivities tochanges in water quality to indicate possible impact from pollutants. Many groups of organisms can beused in the assessment process, ranging from small bacteria and algae up to large vertebrates, such asfish. However, the most popular group of organisms used are the macroinvertebrates. This group, nowused in the Australian Monitoring River Health Initiative (Norris et al 1993), can be recommended dueto the well developed sampling methods, their abundance and heterogeneity and because identificationto species level is not always required. The main advantage of using macroinvertebrate populations asindicators is that there are some species which are highly sensitive (and others which are tolerant) toselected pollutants and due to their relatively sedentary habit they tend to integrate the effect of changesin water quality over time.

i) BiosurveyA survey of the biota in a waterbody, including taxonomic identification and abundance measurements,will give several clues to the quality of a water body when compared to baseline data sets from known,unimpacted sites of a similar waterbody. The structure of the biotic community will adjust to anecosystem impact in accordance with the severity of the impact. Certain taxonomic groupings may belost in the restructuring as the community 'adapts' to the impact and consequently other groups will beadvantaged and increase in numbers. In the case of a toxic impact some overall loss in the variety ofspecies present might occur, and cause an imbalance in ratios between particular taxonomic groups e.g.producers/consumers and filter feeders/grazers. Presence or absence of a particular species may act asan indicator of a particular impact (e.g. a pesticide).

The biota of an ecosystem act as integrators of the impacts or stresses seen over time. Changes seenover each monitoring cycle may indicate improvements or worsening of the situation with regard to the'health' of a waterbody.

49

The main difficulty with biosurveys, especially in regions such as the irrigation areas of NSW, isfinding suitable reference sites which have not been impacted, and can be used to obtain the baselinedata.

ii) Indicator OrganismsIndicator organisms are often identified following a comprehensive biosurvey of an ecosystem eitherbecause of their presence and/or absence, or their abundance. Certain species may be advantaged by animpact (e.g. due to the loss of predators) while others may be resistant to the impact. It follows that thepresence of the abundant species (or the absence of the impacted species) are useful indicators of anenvironmental impact.

Chironomid (midge) larvae have been suggested as useful indicator species as they are widespread inaquatic systems, have great species diversity and certain species are often found in waters known to be'polluted' (eg. waters with high organic matter or with heavy metals contamination).

There are also other approaches such as the study of 'bilateral asymmetry' or deformities in organismsexposed to chemical impact. The mouthparts of chironomids, for example, have been shown to bedeformed due to the presence of both heavy metals and organics (PCBs) in water (Warwick, 1988). MrV. Pettigrove, working in the MIA, has shown convincing correlation of mouthpart deformities ofchironomid larvae, in the 2nd to 4th instar stages, following colonising of rice bays after the pesticidesapplied had decayed to sub lethal levels (Pettigrove et al., 1995). It is suggested by some that thedeformities are a somatic effect of the chemical during larval development and it may be possible tolink a particular deformity, or deformities in particular species to certain chemical types. Assumingthere is no genetic damage the deformity would not be carried to the next generation in which case theexposed larval stages act as integrators of sub-lethal chemical impacts during their lifetime (a few daysto several weeks depending on the species life cycle). Knowledge of their biology will give the timeinterval for each instar and thus the exposure time.

Fluctuating asymmetry is another version of the same phenomenon where differences in anatomybetween each side of the body (e.g. the number of teeth to the left and right side of a mouthpart) aregiven a ratio or index which can be compared to that of a 'normal' population (Clarke, 1993).Variations from the normal are thought to be due to environmental stressors such as chemicals and cantherefore be related to ecosystem impacts. Aquatic insect larvae and small crustacea are considered tobe useful organisms for the examination of such phenomena.

iii) EcotoxicologyEcotoxicology generally uses laboratory cultured organisms under controlled conditions to establish theimpact of a toxin on the organism. There are usually two forms of testing procedures, acute toxicitytests and chronic toxicity tests, both of which are described in Section 4.4. The organisms chosen fortesting may inhabit any part of the food web of an aquatic system and include bacteria, algae,cladocerans (water fleas), chironomids (midge larvae), large crustacea (yabbies), and fish. Aquaticmacrophytes are also used (e.g. duckweed).

In the MIA, effluents from irrigated agriculture have been tested at the CSIRO Griffith Laboratoryusing Ceriodaphnia sp. as the test organism with a modification of the acute and chronic US EPAtesting procedures (US EPA, 1991d). Drainage samples collected daily and containing mixtures ofpesticides were tested for possible chronic and/or acute toxicity (Korth et al. 1995b). The bioassayfrequently indicated higher toxicity than was expected from the chemistry and appropriate LC50 testingof the individual chemicals (Figure 5).

50

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

20/1

0

23/1

0

26/1

0

29/1

0

1/11

4/11

7/11

10/1

1

13/1

1

16/1

1

19/1

1

22/1

1

25/1

1

28/1

1

1/12

4/12

7/12

date

toxi

city

(T

U)

to C

. cf

du

bia

measured toxicity

predicted toxicity

Figure 5: Predicted (from chemistry and LC50s) versus actual toxicity of drainage water collecteddaily from a common drain below a 5 farm catchment at Willbriggie (Korth et al., 1995b).

Clearly, the bioassay has indicated an ecosystem problem that was not predicted by the knownchemistry (Fig 5, 11/11, 15/11, and 20/11 to 7/12). On occasions the effluent was also found to be notas toxic as the chemistry predicted (Fig 5, 21/10 to 23/10 ). Furthermore, other experiments, involvingan MIA creek system, have shown that chronic toxicity can occur regularly during the early part of theirrigation season (Korth et al., 1995a). These results demonstrate that ecotoxicological assays arevaluable in detecting possible ecosystem effects.

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7. PESTICIDE CONCENTRATIONS IN THE IRRIGATIONAREAS OF S-W NSW, A REVIEW OF DATA

In this chapter, a review of the pesticide monitoring that has been carried out in the irrigation areas ofSouth-Western NSW by state agencies and the CSIRO from 1990 to early 1995 is presented. Eachsection provides a summary of the type of monitoring undertaken, the pesticides analysed for, a briefsummary of the results, and a reference where further information can be obtained.

7.1 MIA Surface Water Quality Project 1991-1993

Work carried out by: NSW DWR, assisted by CSIRO Division of Water ResourcesDate of study: 1991 to early 1994Location and frequency ofmonitoring:

MIA: Supply channels and large drainage channels, at approximately 3monthly intervals.

Measurements taken water samples analysed using the following screening tests; herbicides,USEPA methods 3100, and 525; insecticides, USEPA method 507 andorganochlorines, USEPA method 608.

Method of measurement GC-MS and HPLC at DWR labs in Arncliffe, and LLE-GC/MS at CSIROGriffith lab.

Reference: - From Shepheard (1994).- also, for CSIRO raw data, see ‘Griff 21’ in Appendix D.

a) Supply water (from Murrumbidgee River, entering the main canal at Yanco):Water taken from the Murrumbidgee River was high quality, and generally no pesticides were detected(Table 17). The only exception was in September 1992 when atrazine was detected at a level of 0.08µg/L which is well below the drinking water guideline of 20 µg/L and also below the interim guidelinefor the protection of the aquatic environment of 2.0 µg/L.

Table 17 Pesticide concentrations in MIA supply at Yanco, 1991-93pesticide total no. of

samplesno. of

samples >detection

limit

detectionlimit

(ug/L)

max conc.detected(ug/L)

Protection ofaquatic

environment(ug/L)

NHMRCDrinking

waterguidelines

(ug/L)diuron 12 0 0.1,0.05 - 8 30atrazine 12 1 0.1, 0.05 0.08 2 20molinate 12 0 0.1,0.05 - 2.5 5malathion 12 0 0.1,0.05 - 0.07 50bromacil 12 0 1.0,0.5 - 100 300

Note: Detection limits varied depending on which laboratory analysed the sample

b) Water in the large drainage channelsWater in the large drainage channels of the Murrumbidgee Irrigation Area contain runoff from a varietyof crops, and pesticide residues are present, particularly in spring and summer. The two pesticidesmost often detected in drainage water were diuron and molinate (Table 18). Diuron originates fromcitrus orchards and from the direct application to drainage channels for the control of aquatic weeds,and was detected throughout the year. Molinate was detected in most drains during October-Decemberwhen it is being applied to rice fields, and on occasions exceeded both the guidelines for drinking waterand for protection of the aquatic environment. In October 1993 the concentration of molinate indrainage water leaving the MIA, which was supplied to the Wah Wah Irrigation District for stock and

52

domestic purposes, exceeded drinking water quality guidelines and resulted in a drainage ban beingimplemented by the DWR. Malathion, an insecticide used on rice crops, was also detected in theOctober-December period, although not as frequently as molinate. The maximum levels detected ofmalathion, atrazine and diuron all exceeded the guidelines for ecosystem protection but not the drinkingwater guidelines.

Table 18 Pesticide concentrations in large drains of the MIA, 1991-93 pesticide no. of

samplesno. of

samples >detection

limit

detectionlimit

(ug/L)



environment(ug/L)

NHMRCDrinking

waterguidelines

(ug/L)diuron 71 29 0.1,0.05 9.5 8 30atrazine 71 9 0.1,0.05 5.4 2 20molinate 71 32 0.1,0.05 37.5 2.5 5malathion 71 6 0.1,0.05 1.8 0.07 50bromacil 71 10 1.0,0.5 4.9 100 300

Note 1; Drains tested were Yanco Main Southern, Gogeldrie Main Southern, Little Mirrool Creek,Main Drain J, Mirrool Creek at McNamara Road, Willow Dam and Wah Wah Channel 1.Note 2; Detection limits varied depending on which laboratory analysed the sample

53

7.2 MIA Surface Water Quality Project, 1994-95

Water quality monitoring by the NSW DWR continued in the MIA through the 1994-95 season on amonthly basis. Results are summarised in Table 19.

Comments;• Molinate concentrations were very high in November, with a maximum concentration of 300 µg/L

which exceeds environmental guidelines by 120 times. It was detected in all drainage samples andone re-supply sample (Benerembah supply channel).

• There was a large number of drainage samples containing endosulfan during December, including avalue as high as 2.5 µg/L, which not only exceeds the environmental guidelines but would alsocause fish kills (the lethal concentration for carp is 0.1 µg/L, for golden perch 0.3 µg/Land forsilver perch 2.3 µg/L (Sunderam et al 1992)).

• The only sampling site where no pesticides were detected was the main supply at the Narranderaregulator.

Table 19 Pesticide concentrations in MIA surface water, 1994-1995 seasonMonthly results, showing number of samples > detection limit (and max concentration detected in brackets).chemical detect

limitug/L

env.guide.ug/L

Sept. Oct. Nov. Dec Jan Feb Mar Apr May

diuron0.1 8

5(3.4)

12(5.4)

6(1.4)

6(2.7)

1(0.82)

2(0.72)

2(0.45)

2(0.22)

8(0.68)

simazine0.1 10

1(1.1)

3(0.8)

2(4.8)

6(0.33)

3(0.16)

atrazine0.1 2

1(0.15)

3(0.7)

6(1.9)

2(3.5)

4(4.4)

2(0.16)

1(0.72)

2(0.1)

diazinon0.1 .0006

1(0.13)

bromacil0.1 100

3(1.8)

3(1.4)

1(0.18)

3(0.53)

MCPA0.5 232

1(0.15)

1(0.7)

2,4-D0.5 4

1(5.7)

2(2.0)

totalendosulfan 0.01 0.01

1(0.08)

3(0.06)

7(.034)

10(2.51)

11(0.73)

11(0.49)

9(0.13)

7(0.64)

3(.033)

chlorpyrifos0.01 0.001

malathion0.1 0.07

1(0.69)

4(0.47)

thiobencarb0.1 1

6(2.4)

metolachlor0.1 8

3(0.68)

4(2.2)

molinate0.1 2.5

8(15)

15(300)

12(5.6)

2(0.24)

total no. ofdetections

9 33 55 40 22 21 12 9 6

no. > env.guidelines

1 7 25 14 12 11 9 7 3

18 sites were sampled once per month, comprising 2 supply sites, 2 re-supply sites, 1 swamp, 2 lake sites, 1 creek and 10drain sites. Maximum concentrations detected are in ug/L.

54

7.3 CIA Surface Water Quality Data Report 1991-1993

Work carried out by: NSW DWR, with assistance from CSIRO Division of Water ResourcesDate of study: 1991 to early 1994Location and frequency ofmonitoring:

CIA: Supply channel at Sturt Hwy and large drainage channels. Samplestaken at 3 monthly intervals in 1991 to 1993, and then weekly in 1993/94.

Measurements taken - water and sediment samples analysed using the following screening tests;herbicides, USEPA methods 3100 and 525; insecticides, USEPA method 507and organochlorines, USEPA method 608.- Chironomid bioassays

Method of measurement GC-MS and HPLC at DWR labs in Arncliffe and LLE-GC/MS at CSIRO labin Griffith.

Reference: - From Buchan (1994), and additional information from Alistair Buchan atNSW DWR office in Leeton.- For raw data of samples analysed by CSIRO, see ‘Griff 21’ in Appendix D.

a) Supply water (from Murrumbidgee River, entering Coleambally Canal at Sturt Hwy):The supply water entering the Coleambally irrigation Area (CIA) from the Murrumbidgee River is of ahigh quality, and generally no pesticides are detected (Table 20). The only incident of concern was inJanuary 1994 when endosulfan sulphate was detected at a concentration of 0.02 µg/L, which is abovethe guideline for the protection of the aquatic environment of 0.01 µg/L, but well below the drinkingwater guideline of 30 µg/L.

Table 20 Pesticide concentrations in CIA supply at Sturt Hwy, 1991-94pesticide total no.

ofsamples

no. ofsamples >detection

limit

detectionlimit

(ug/L)



environment(ug/L)

NHMRCDrinking

waterguidelines

(ug/L)endosulfan 13 1 0.01 0.02 0.01 30atrazine 21 0 0.1,0.05 - 2 20molinate 19 0 0.1,0.05 - 2.5 5diuron 19 0 0.1 - 8 30simazine 13 0 0.1 - 20malathion 20 0 0.1 - 0.07 50trifluralin 20 0 0.1 - 50diazinon 20 0 0.1 - 0.00006 3chlorpyrifos 20 0 0.01 - 0.001 2thiobencarb 20 0 0.1 - 30metolachlor 13 1 0.1 0.1 8 300

b) Water in the large drainage channelsMolinate was the most commonly detected pesticide (Table 21), with levels reaching as high as 50 µg/Lduring spring, when it is being applied to rice crops. This greatly exceeds both the drinking waterquality guidelines (5 µg/L) and the guidelines for the protection of the aquatic environment (2.5 µg/L).Atrazine and endosulfan was also detected in a high proportion of samples, particularly in Dec 1993 -Jan 1994. Other pesticides which were detected in more than 10% of samples were diuron, thiobencarband metolachlor.

c) Sediment analysesSediment sampling indicated that molinate is only detected when high levels are also present inthe overlying water body.

55

Table 21 Pesticide concentrations in large drains of the CIA, 1991-93pesticide total no.

ofsamples

no. ofsamples >detection

limit

detectionlimit

(ug/L)

max conc.Detected

(ug/L)


environment(ug/L)

NHMRCDrinking water

guidelines(ug/L)

endosulfan 39 15 0.01 0.25 0.01 30atrazine 58 20 0.1,0.05 5.7 2 20molinate 51 40 0.1 50.3 2.5 5diuron 57 9 0.1 3.7 8 30simazine 39 2 0.1 0.1 20malathion 60 4 0.1 0.8 50trifluralin 60 0 0.1 - 50diazinon 60 2 0.1 0.1 3chlorpyrifos 60 1 0.01 0.1 10thiobencarb 60 7 0.1 1.5 30metolachlor 39 9 0.1 6 8 300

Note; Drains tested were Coleambally outfall drain (below all drainage canals), and drainage canals500A 800A, 400A & 600A..

d) Chironomid BioassaysIn general terms, the level of deformities (6-13% in drains) has indicated that there is some mild biociderelated stress to chironomid populations in drains when compared with deformities in populations fromsupply water (4%). This is consistent with the results of chemical analyses of drainage water.

56

7.4 CIA Surface Water Quality Monitoring 1994-95

Water quality monitoring by the NSW DWR continued in the CIA through the 1994-95 season on amonthly basis. Results are summarised in Table 22.

Comments;• Molinate and endosulfan were both detected in the supply channel within the CIA, in November.

This is probably due to overspraying or spray drift during aerial spraying.• Endosulfan was detected in the drainage canals for all months from October 1994 to June 1995.• Environmental guidelines were exceeded in drainage water for endosulfan (all months tested),

molinate (in October-December) and on one occasion for thiobencarb (in October).• No pesticides were detected in the main Coleambally supply.

Table 22 Pesticide concentrations in CIA surface water, 1994-1995 seasonMonthly results, showing number of samples > detection limit (and max concentration detected is recorded inbrackets).chemical detect

limitug/L

env.guide.ug/L

Oct. Nov. Dec Jan Feb Mar Apr May Jun

diuron0.1 8

1(0.3)

simazine0.1 10

1(0.2)

atrazine0.1 2

1(0.35)

2(0.3)

2(0.13)

1(0.21)

2(0.3)

MCPA0.5 232

1(0.59)

2,4-D0.5 4

2(2.1)

totalendosulfan 0.01 0.01

2(.03)

3(.028)

1(.013)

1(.011)

2(0.1)

2(.09)

2(.036)

2(0.03)

2(0.07)

malathion0.1 0.07

thiobencarb0.1 1

1(2.7)

molinate0.1 2.5

2(13)

3(20)

2(6.9)

1(0.45)

1(0.1)

total no. ofchemicaldetections

5 7 6 4 7 2 2 1 5

exceedanceof guidelines

5 5 2 1 2 2 2 1 2

4 sites were sampled once per month, comprising of 2 drainage sites (CODA and DC800A), the main supply (CCS) andan internal supply canal (CE160-2). Maximum concentrations detected are in ug/L.

57

7.5 Murray Valley Surface Water Quality Report

Work carried out by: NSW DWR, Murray Region.Date of study: 1990 to 1994Location and frequency ofmonitoring:

Water samples taken at Mulwala canal offtake at Lake Mulwala (supplywater), 5 creeks and drains within the irrigation districts, and in theWakool River at Kyalite. Samples collected in September, November,March and June, plus some additional samples for quality assurance or tomonitor particular events.Sediment samples also collected from March 1993 onwards.

Measurements taken Samples analysed for amitrole, atrazine, bensulfuron, chlorpyrifos, 2,4-D,diazinon, diuron, glyphosate, malathion, MCPA, molinate, TCA,thiobencarb and trichlorfon.

Method of measurement Water Environment Laboratory (Arncliffe, NSW) and State WaterLaboratory (Armadale, Vic.). Analyses were by GC-MS or HPLC.

Reference: O’Connell (1994).

The results indicate that pesticides are frequently found in surface waters of the Murray Region. Of the14 pesticides selected for analysis, 8 were found in water samples. All of these were herbicides, withnone of the four insecticides detected. Pesticides were detected most frequently at Box Creek (52% ofsamples), Tuppal Creek (29%) and Niemur Drain (28%). Surprisingly, on three occasions the samplestaken from the Mulwala supply offtake also tested positive.

On six occasions molinate exceeded the guidelines for the protection of aquatic ecosystems (2.5 µg/L),and four of these also exceeded the drinking water guidelines (5 µg/L). The maximum concentration of36 µg/L was recorded in November 1992 in the Niemur drain and is 14 times higher than the guidelinesfor ecosystem protection. The other herbicides detected were diuron, atrazine, bensulfuron, MCPA,2,4-D, glyphosate and thiobencarb.

Although all sites recorded some positive results in water samples, three sites showed particularly highincidence of contamination. These were Box Creek and Tuppal Creek, which receive drainage waterfrom the Berriquin Irrigation District, and Niemur Drain, which drains the Deniboota and Wakool-Tullakool Irrigation Districts. Both Box Creek and Tuppal Creek release water into the Edward River,and Niemur drain releases water into the Niemur River.

River water leaving the region was represented by the samples taken in the Wakool River at Kyalite.The one positive sample obtained here, molinate in March 1994, was coincident with three otherpositive samples for molinate in drainage water at other sampling sites.

On a monthly scale, both the greatest number and highest levels of pesticides were detected inSeptember and November. In September, the common pesticides detected were diuron, atrazine andbensulfuron, and in November they were atrazine, bensulfuron and molinate.

Sediment samples were taken at most sites from March 1993 to June 1994. Of the eight pesticidesselected for analysis, only one herbicide, molinate, tested positive in November 1993, at three sitesreceiving drainage water, with a maximum concentration of 0.03 mg/kg. In each case molinate wasalso detected in the overlying water.

58

7.6 Toxicity of rice and maize pesticides from 5 farms atWillbriggie, MIA.

Work carried out by: CSIRO, Division of Water Resources, Griffith.Date of study: 16th October to 9th December 1993 (start of irrigation season), and 2nd to

13th March 1994 (end of season)Location and frequency ofmonitoring:

Drainage channel common to a catchment of five rice and maize farms atWillbriggie, 20km south of Griffith in the MIA. The ‘upstream’ site was1.2 km below the start of the common drain, and the ‘downstream’ sitewas 3.1 km below the common drain.Supply water for these five farms was also tested (at Sturt Canal Supply,branch off Adams Rd).Samples were 24hr composites consisting of 150mls every 30 minutes.

Measurements taken - chemical analyses for chlorpyrifos, malathion, molinate, atrazine,metolachlor, thiobencarb, glyphosate, and bensulfuron- toxicity tests using Ceriodaphnia sp.

Method of measurement LLE-GC/MSReference: - Korth et al (1995b)

- Raw data; see ‘Griff 4’ (upstream sampling site), ‘Griff 5’ (downstreamsite) , ‘Griff 6’ (supply water) and ‘Griff 12’ (March 1994 data) ofAppendix D

Supply and drainage water were monitored by the CSIRO at the beginning of the irrigation season(16th October - 9th December 1993) and again at the end of the irrigation season (2nd march to 11th

march 1994) in a small catchment at Willbriggie, 20km south of Griffith in the MIA. The five farmswithin the catchment were growing rice and maize. Pesticides used during the study includedchlorpyrifos, malathion, molinate, thiobencarb, and bensulfuron-methyl for rice, and atrazine andmetolachlor for maize. Daily composite samples (consisting of subsamples taken every 30 minutes)were taken from the supply channel and at two locations in the drainage channel. The ‘upstream’ sitewas 1.2 km below the start of the common drain, and the ‘downstream’ site was 1.9 km furtherdownstream. No additional drainage water entered between the two sites.)

Pesticides in supply water entering the catchment.As supply water passes through the irrigation areas, there is the potential for it to become contaminatedwith low concentrations of pesticides due to spray drift or overspray. Also, in some regions (such asthe farms at Willbriggie), supply water is shandied with drainage water from upstream irrigation areas.Pesticide contamination of these shandied supplies is highly likely, and was confirmed by measurementsof supply water for the farms in this study. Contamination was generally low and infrequent with theexception of molinate which was detected in 90% of samples. Maximum concentrations detected(µg/L) and the proportion (%) of samples in the 55 day monitoring period showing detectableconcentrations were as follows:

- atrazine 0.35 µg/L (20%)- malathion 0.06 µg/L (2%)- chlorpyrifos 0.05 µg/L (2%)- molinate 3.6 µg/L (90%).

Although the maximum concentrations of both chlorpyrifos and molinate exceeded water qualityguidelines for the protection of the aquatic ecosystem of 0.001 µg/L for chlorpyrifos and 2.5 µg/L formolinate, they were both below the drinking water guidelines of 10 µg/L for chlorpyrifos and 5 µg/Lfor molinate. The high frequency of contamination is due to the measurements being taken in springand early summer when these pesticides are being applied to crops throughout the MIA. Contaminationof shandied supply water would be expected to be much less frequent during other periods of the year.

59

Pesticides in drainage water at the ‘upstream’ siteAll pesticides that were used on either the rice or maize crops were detected during the monitoringperiod. The maize herbicides, atrazine and metolachlor, were detected at high levels (a maximum of 88µg/L for atrazine and 140 µg/L for metolachlor) in drainage water immediately after application inearly November and then persisted at lower levels throughout the first monitoring period (Figure 6a).For most of this period both of these herbicides exceeded the water quality guidelines for ecosystemprotection (2 µg/L for atrazine and 8 µg/L for metolachlor). Atrazine also exceeded the drinking waterguideline of 20 µg/L on a number of occasions. Both herbicides were again detected in the secondmonitoring period at the end of the irrigation season (March 1994), but only at low levels (between 0.05and 3.0 µg/L for both chemicals).

The concentration of molinate in drainage water behaved in a similar manner, with peak levelsoccurring in October-November 1993 when it was being applied to rice crops within the catchment(Figures 6b). Peak concentrations (up to 269 µg/L) greatly exceeded the water quality guideline forecosystem protection (2.5 µg/L) and also the drinking water quality guideline (5 µg/L). Towards theend of the irrigation season (March 1994) molinate was only detected at very low levels (less than 1.0µg/L).

Malathion, chlorpyrifos and thiobencarb (Figure 6c and 6d) were only detected in short pulses and didnot persist throughout the season. The maximum levels for each of these pesticides exceeded the waterquality guidelines for ecosystem protection, but did not exceed drinking water guidelines.

0

20

40

60

80

100

120

140

16/1

0

20/1

0

24/1

0

28/1

0

1/11

5/11

9/11

13/1

1

17/1

1

21/1

1

25/1

1

29/1

1

3/12

7/12 3/3

7/3

11/3

date

con

cen

trat

ion

(u

g/L

)

atrazine

metolachlor

2nd March

Figure 6a : Concentration of atrazine and metolachlor (maize herbicides) detected in drainage watercollected daily at the upstream site

60

0

50

100

150

200

250

300

16/1

0

20/1

0

24/1

0

28/1

0

1/11

5/11

9/11

13/1

1

17/1

1

21/1

1

25/1

1

29/1

1

3/12

7/12 3/3

7/3

11/3

Date

con

cen

trat

ion

(u

g/L

) Molinate

2nd March

Figure 6b: Concentration of molinate, (a rice herbicide) detected in drainage water collected at theupstream site.

0

1

2

3

4

5

6

16/1

0

20/1

0

24/1

0

28/1

0

1/11

5/11

9/11

13/1

1

17/1

1

21/1

1

25/1

1

29/1

1

3/12

7/12 3/3

7/3

11/3

Date

Co

nce

ntr

atio

n (

ug

/L)

malathion

thiobencarb

Bensulfuron

2nd March

Figure 6c: Concentration of thiobencarb and bensulfuron (rice herbicides), and malathion (a riceinsecticide) detected in drainage water (24h composite samples) collected daily at the upstream site

61

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

16/1

0

20/1

0

24/1

0

28/1

0

1/11

5/11

9/11

13/1

1

17/1

1

21/1

1

25/1

1

29/1

1

3/12

7/12 3/3

7/3

11/3

Date

con

cen

trat

ion

(u

g/L

)

Chlorpyrifos 2nd March

Figure 6d: Concentration of chlorpyrifos (rice insecticide) detected in drainage water collected daily atthe upstream site.

c) Toxicity of drainage waterLethal and sublethal toxic effects of the selected pesticides were determined in the laboratory usingCeriodaphnia sp. (Table 23). LC50’s (concentration lethal to 50% of the test organisms), NOEL’s (noobserved effect levels) and LOEL’s (lowest observed effect levels) for molinate, chlorpyrifos andmalathion in irrigation supply water were determined.

Table 23 Acute toxicity (LC50) of Ceriodaphnia sp. to selected pesticidespesticide LC50 (ug/L)chlorpyrifos 0.25malathion 1.44molinate 430atrazine 18,300metolachlor 1,950thiobencarb 260glyphosate 7,990bensulfuron >30,000

Ceriodaphnia sp. was subsequently used to assess the toxicity of drainage water at the ‘upstream’ and‘downstream’ sites (approx 2km apart) in the 5 farm rice and maize sub-catchment area.

The drainage water samples were found to be toxic to Ceriodaphnia sp. on 22 occasions; 15 at theupstream site and 7 at the downstream site (Figure 7a). Several of the observed toxic events werematched by the presence of malathion. Observed toxicity was often higher than predicted from thelaboratory toxicity values, probably reflecting the presence of unmeasured toxic compounds in drainagewater, and/or synergy between known toxicants.

d) Reduction in toxicity between upstream and downstream sitesA reduction in toxicity between the upstream and downstream sites pointed to a dissipation in pesticideconcentration along the drainage channel. A greater reduction in downstream pesticide

62

concentrations was observed for the insecticides malathion (Figure 7c) and chlorpyrifos (Figure 7e)than for the herbicides atrazine (Figure 7b), metolachlor and molinate (Figure 7d). Malathion andChlorpyrifos have higher Koc values than the other chemicals and are more likely to be removed fromsolution through adsorption onto sediment particles and other surfaces (such as the leaves of aquaticplants) as they are transported along the drainage channel.

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

16/1

0

19/1

0

22/1

0

25/1

0

28/1

0

31/1

0

3/11

6/11

9/11

12/1

1

15/1

1

18/1

1

21/1

1

24/1

1

27/1

1

30/1

1

3/12

6/12

9/12

date

toxi

city

(T

U)

upstream

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

16/1

0

19/1

0

22/1

0

25/1

0

28/1

0

31/1

0

3/11

6/11

9/11

12/1

1

15/1

1

18/1

1

21/1

1

24/1

1

27/1

1

30/1

1

3/12

6/12

9/12

date

toxi

city

(T

U)

dow nstream

Figure 7a: Toxicity to Ceriodaphnia sp. of upstream and downstream sites

63

0

10

20

30

40

50

60

70

80

90

16/1

0

19/1

0

22/1

0

25/1

0

28/1

0

31/1

0

3/11

6/11

9/11

12/1

1

15/1

1

18/1

1

21/1

1

24/1

1

27/1

1

30/1

1

3/12

6/12

9/12

date

con

cen

trat

ion

(u

g/L

)

upstream

dow nstream

Figure 7b: Concentration of atrazine at upstream and downstream sites of a 2kmlong drainage channel.

0

1

2

3

4

5

6

16/1

0

19/1

0

22/1

0

25/1

0

28/1

0

31/1

0

3/11

6/11

9/11

12/1

1

15/1

1

18/1

1

21/1

1

24/1

1

27/1

1

30/1

1

3/12

6/12

9/12

date

con

cen

trat

ion

(u

g/L

)

upstream

dow nstream

Figure 7c: Concentration of malathion at upstream and downstream sites of a 2km longdrainage channel.

64

0

50

100

150

200

250

300

16/1

0

19/1

0

22/1

0

25/1

0

28/1

0

31/1

0

3/11

6/11

9/11

12/1

1

15/1

1

18/1

1

21/1

1

24/1

1

27/1

1

30/1

1

3/12

6/12

9/12

date

con

cen

trat

ion

(u

g/L

)

upstream

dow nstream

Figure 7d: Concentration of molinate at upstream and downstream sites of a 2kmlong drainage channel.

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

16/1

0

19/1

0

22/1

0

25/1

0

28/1

0

31/1

0

3/11

6/11

9/11

12/1

1

15/1

1

18/1

1

21/1

1

24/1

1

27/1

1

30/1

1

3/12

6/12

9/12

date

con

cen

trat

ion

(u

g/L

)

upstream

dow nstream

Figure 7e: Concentration of chlorpyrifos at upstream and downstream sites of a 2kmlong drainage channel.

65

0

20

40

60

80

100

120

140

160

9/11

11/1

1

13/1

1

15/1

1

17/1

1

19/1

1

21/1

1

23/1

1

25/1

1

27/1

1

29/1

1

1/12

3/12

5/12

7/12

9/12

date

con

cen

trat

ion

(u

g/L

)

upstream

dow nstream

Figure 7f: Concentration of metolachlor at upstream and downstream sites of a 2kmlong drainage channel.

66

7.7 Pesticide dissipation in rice bays

Work carried out by: CSIRO, Division of Water Resources, Griffith.Date of study: 11th October 1991- 5th November 1991Location and frequency ofmonitoring:

Two rice farms, a) Murray Rd, b) Hanwood Avenue in the MIA. Samplestaken daily near inlet and outlet of rice bays.

Measurements taken molinate, malathion and chlorpyrifosMethod of measurement LLE-GC/MSReference: - Bowmer et al (1994), Bowmer and Korth (1994)

- Additional unpublished information from Korth, CSIRO Division ofWater Resources, Griffith.- Raw data, see ‘Griff 8’ of Appendix D.

Results are available for dissipation of molinate (a herbicide), malathion, and chlorpyrifos (insecticides)from rice floodwater (standing water in aerially sown rice). Typical results are shown in Figures 8, 9and 10 where A and B are sampling stations closest to the inlet and outlet respectively.

Initial concentrations of chlorpyrifos measured within a few hours of spraying, reached only about 5µg/L maximum concentration. The concentrations measured are much lower than the expected value of50 µg/L, assuming no loss from the water and 10cm water depth evenly distributed through the bays.Concentrations declined to about 0.2 µg/L within 2 weeks after application. This concentration is still200 times higher than the concentration specified in the water quality guidelines for the protection of theaquatic environment (see Table 13).

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Figure 8 Concentration of chlorpyrifos in rice floodwater with time after application (trial 59). Note that A and B are sampling stations closest to inlet and outlet respectively.

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Molinate concentrations remained high (>~100 µg/L) for at least 2 weeks after treatment (Figure 9 and10). Dissipation half lives for molinate, chlorpyrifos and malathion were 4.5, 2.2 and 1.5 daysrespectively. Under these circumstances, calculated on-farm retention time for floodwater to ensuredissipation of each pesticide from initial (theoretical) to water quality guideline values for the protectionof the aquatic ecosystem were; molinate, 43 days; chlorpyrifos 34 days; and malathion, 13 days. Thisinformation is essential when developing management strategies which involve allowing natural lossprocesses to reduce pesticide concentrations.

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Figure 9b: Concentration of molinate in rice floodwater with time after application. (Trial 60)Note: apparently a second application was made about 2 weeks after the first.

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Figure 10 Concentration of malathion in rice floodwater after application on 18th October. (trial59). Note that A and B are sampling stations closest to inlet and outlet respectively.

7.8 Pesticides in drainage water leaving individual farms

Work carried out by: CSIRO, Division of Water Resources, Griffith.Date of study: Oct-Nov-Dec 1992 and 1993, and also March 1994Location and frequency ofmonitoring:

Samples taken at farm drain exits of rice farms in Willbriggie.

Measurements taken 1992; Molinate, atrazine, malathion, chlorpyrifos, thiobencarb, diuron andbromacil. In 1993 and 1994, also tested for thiobencarb, bensulfuron,endosulfan, and cypermethrin

Method of measurement LLE-GC/MS at CSIRO Lab, GriffithReference: Raw data, see ‘Griff 7’, ‘Griff 9’, ‘Griff10’ and ‘Griff13’ of Appendix D

a) In 1992 and 1993 (October-December), individual farm drains in the Willbriggie catchment weremonitored to determine pesticide levels. Pesticides detected in grab samples of drainage water (taken asthe drainage water left the farms), showed the following maximum concentrations:

maximumconcentration

(µg/L)

molinate 700malathion 30chlorpyrifos 25atrazine 79metolachlor 120thiobencarb 3bensulfuron 4.9

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In March 1994, at the end of the growing season when most pesticide spraying programs had beencompleted, all farms were re-tested and the maximum concentrations were much lower:

maximumconcentration

(µg/L)

molinate 0.3atrazine 1.1metolachlor 3.2bensulfuron 0.08thiobencarb 0.24.chlorpyrifos not detected

b) In 1992 (October) individual rice farms that were draining floodwater were monitored at the farmdrain exit. Pesticide concentrations determined in the drainage water were compared to the pesticideconcentrations found in the nearest rice bay of the farm. The maximum concentrations of ricepesticides detected in the bays and drains are shown below:

Maximum Concentrations (µg/L)Rice Bays Drains

molinate 1840 1480malathion 25 15chlorpyrifos 38 7.1

On at least one occasion (when a malathion concentration of 15 µg/L was detected), aerial overspray ofthe drain with malathion impregnated rice was indicated.

In general if rice floodwater overflowed to the drain, as opposed to seeping through rice bay banks orleaking at control gates, the difference in concentration of pesticide residues detected in the bayfloodwater compared with the concentration in the drainage water, was minimal.

7.9 Pesticide export from a rice-pasture area - 1991 sampling

Work carried out by: CSIRO, Division of Water Resources, Griffith.Date of study: 9th October-29th November 1991, and 5th March - 9th April 1992Location and frequency ofmonitoring:

drainage water from a broadacre rice-pasture catchment (15 farms) atWillbriggie, MIA.

Measurements taken daily samples of drainage water over 55 day period beginning on 9th October1991.

Method of measurement LLE-GC/MS at CSIRO Lab, GriffithReference: - Bowmer et al (1994), Bowmer and Korth (1994).

- Raw data, see ‘Griff 1’ and ‘Griff 2’ of Appendix D.

Chorpyrifos (aerially sprayed for bloodworm control) and malathion (a seed dressing for the samepurpose) both appeared in discrete pulses (Figure 11), perhaps reflecting overspraying and aerialseeding from rice fields overlapping into the drainage channels.

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Molinate increased steadily in concentration during the first 10 days of monitoring (Figure 12) and thenmaintained levels in the range 1-100 µg/L. Contamination may reflect overtopping and seepage fromaerial-sown rice, or flushing after application to dry soil in a single drill-sown crop.

Atrazine concentrations were surprisingly high and consistent (Figure 12). The herbicide was used as asoil sterilant for aquatic weed control in drainage channels and also was applied to a maize crop on asingle farm. The loss of atrazine represented only a very small proportion of the herbicide applied (lessthan 0.5%). As expected, loads and concentration of atrazine were higher in the first “flush” (watering)than in subsequent drainage events.

Average concentrations of molinate exceeded water quality guidelines for the safety of aquaticecosystems by more than 30 fold; malathion by 3 fold, chlorpyrifos by 170 fold and atrazine by 20 fold(Table 24).

Table 24 Fluxes of pesticides and nutrients from a rice-pasture catchment in Willbriggie, south ofGriffith, with a total area of 2129 ha including about 600 ha of rice

chemical flux averageconcentration(µg/L)

water qualityguidelines forecosystem protection(µg/L)

water 270 MLTotal N 322 kg 1200Total P 17.7 kg 65molinate 20.1 kg 75 2.5malathion 56 kg 0.21 0.07chlorpyrifos 45 kg 0.17 0.001atrazine 12.2 kg 45 2

Note: water quality guidelines were derived from ANZECC (1992) or NSW EPA interim guidelines

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Figure 11 Malathion and chlorpyrifos in drainage water from rice-pasture catchment

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Figure 12 Molinate and atrazine in drainage water from rice-pasture catchment

7.10 Pesticide export from a rice-pasture area - 1993-94 sampling

Work carried out by: CSIRO, Division of Water Resources, Griffith.Date of study: 16th October to 9th December 1993 and 1st-11th March 1994.Location and frequency ofmonitoring:

drainage water from a broadacre rice-pasture catchment (15 farms) atWillbriggie, MIA.

Measurements taken water samples tested for molinate, malathion, thiobencarb, chlorpyrifos,bensulfuron, atrazine, metolachlor, diuron, bromacil

Method of measurement LLE-GC/MS at CSIRO Lab, GriffithReference: - Bowmer and Korth (1994)


Concentrations of molinate and atrazine were similar to those measured in 1991 (see section 7.9) andwere generally in the order of 10-100 µg/L, which exceeds both drinking water guidelines andguidelines for the protection of the aquatic environment. Pulses of chlorpyrifos and malathion did notexceed 1 µg/L which is an order of magnitude smaller than those recorded in 1991. However bothcompounds still exceeded their respective water quality guidelines for ecosystem protection by severalorders of magnitude. The detection of short term pulses of pesticide contamination confirms the needfor a frequent sampling regime.

Monitoring in March 1994 (which is after the spraying season for rice) only detected very lowconcentrations of molinate, atrazine, metolachlor and bensulfuron (all less than 1 µg/L) and did notdetect malathion or chlorpyrifos.

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7.11 Runoff from summer cropping (maize)

Work carried out by: CSIRO, Division of Water Resources, Griffith.Date of study: December 1991Location and frequency ofmonitoring:

Water samples taken from furrows every 10-20 minutes over entireirrigation event

Measurements taken farm A (atrazine applied at 1.23 kg/ha), tailwater in two furrows sampledduring first irrigation only.farm B (atrazine applied at 1.1 kg/ha), tailwater in two furrows sampledduring 1st, 2nd and 4th irrigations.

Method of measurement LLE-GC/MSReference: - Bowmer and Korth (1994), Bowmer et al (1994)


Irrigation waters draining from the furrows of two maize farms were monitored for atrazine. Atrazinewas surface applied on both crops at 1.23 kg/ha (farm A) and 1.1 kg/ha (farm B). Runoff hydrographsand atrazine concentrations in irrigation drainage waters were measured during the first irrigation onboth farms. The loss of atrazine represented only a very small proportion of the herbicide applied(<0.5%). Maximum initial atrazine concentrations were 23 and 145 µg/L while averageconcentrations, measured over the entire first irrigation event, were 6 and 33 µg/L for farms A and Brespectively. Second and fourth irrigation events were also monitored for atrazine on farm B. Asexpected, loads and concentrations of atrazine were much higher in the first irrigation runoff than insubsequent runoff events. The potential of atrazine damage to sensitive crops, such as germinatingrice, needs to be considered if the practice of recycling tailwater is used as a management strategy.

7.12 Tile drainage from horticulture

Work carried out by: CSIRO, Division of Water Resources, Griffith.Date of study: January, May, and August 1992, and August 1994.Location and frequency ofmonitoring:

January 1992; snapshot of 49 horticultural farms in the MIA growingcitrus, grapes and stonefruit.May1992; 8 collections over a 2 week period of the same 49 farmsAugust 1992; 3 collections over a 2 week period of 48 of the same farmsAugust 1994; snapshot of selected drains

Measurements taken Tile drainage water analysed for bromacil, diuron, atrazineMethod of measurement GC/MS;

In May and September 1992 diuron was also measured using ELISAimmunoassay kits.

Reference: - Bowmer and Korth (1994), Bowmer et al (1994)- Immunoassay results are reported in Lee et al (in press)- Raw data, see ‘Griff 17’, ‘Griff 18’ and ‘Griff 19’ in Appendix D.

Tile (sub-surface) drainage water was monitored for bromacil and diuron at 49 horticultural farms inthe MIA on three occasions in 1992 (January, May and August). The sampling period in May was themost intensive involving the collection of 8 samples per farm over a 14 day period. Approximately28% of the 49 farms monitored, contained detectable levels of both bromacil (>0.50 µg/L) and diuron(>0.05 µg/L). Furthermore, an additional ~ 10% of the farms showed detectable levels of eithercompound. Generally, the same farms were positive with respect to either or both compoundswhenever monitored. Maximum concentrations detected for bromacil and diuron were 11 and 28 µg/Lrespectively. Investigation of on-farm management practices indicated that those farms usingherbicides to control weeds were likely to have detectable levels of these compounds in their sub-surface drainage water.

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7.13 Surface water runoff from a citrus farm

Work carried out by: CSIRO, Division of Water Resources, Griffith, in conjunction with theNSW Dep’t of Agriculture

Date of study: November 1992Location and frequency ofmonitoring:

Citrus farm at Merungle Hill, MIA. Samples taken for 6 hours during firstirrigation (although runoff from a storm had already occurred sinceherbicide application). Subsurface drainage 2 weeks after the firstirrigation event was also analysed.

Measurements taken Irrigation surface runoff and subsurface drainage both analysed for diuronand bromacil

Method of measurement GC/MSReference: - Bowmer and Korth (1994)


Surface water runoff from a citrus farm was monitored following the application of bromacil anddiuron. Heavy rainfall prior to irrigation prevented the collection of the initial flush of surface waterrunoff. However, samples were collected following the first irrigation event. Concentration ranges forbromacil and diuron were 2.2 to 15 µg/L, and 1.2 to 20 µg/L respectively over the monitoring period(~6 hrs). Sub-surface drainage water sampled two weeks after the first irrigation event showeddetectable levels of both herbicides (bromacil 2.7 µg/L, diuron 1.3 µg/L).

7.14 Grab samples from Mirrool Creek, 1991

Work carried out by: CSIRO, Division of Water Resources, Griffith.Date of study: 26/11/91Location and frequency ofmonitoring:

snapshot of water quality in Mirrool Creek at all road crossings betweenand including Darlington Point Rd and Willow Dam.

Measurements taken Grab samples tested for molinate, chlorpyrifos, atrazine, diuronMethod of measurement GC/MSReference: not published

Molinate was detected at all six locations along Mirrool Creek, ranging between 7.1 µg/L to 18 µg/L.These concentrations are all well above the value of 2.5 µg/L which is the guideline for protection ofthe aquatic environment and also above the drinking water guideline of 5 µg/L (NHMRC 1994).Diuron was also detected at all locations, ranging from 0.06 µg/L to 0.17 µg/L. At two locations highconcentrations of chlorpyrifos were also detected. Atrazine was detected at three of the six siteswhereas malathion was not detected at all.

Table 25 Pesticide levels in Mirrool Creek, November 1991molinate

(ug/L)malathion

(ug/L)chlorpyrifos

(ug/L)atrazine

(ug/L)diuron(ug/L)

site A, Darlington Pt Rd 10 <0.05 <0.05 0.06 0.06site B, Gum Creek Rd 11 <0.05 <0.05 0.06 0.09site C, Drew Rd 18 <0.05 17 2.2 0.09site D, Brogden Rd 16 <0.05 <0.05 <0.05 0.17site E, McNamara Rd 7.2 <0.05 14 <0.05 0.11site F, Willow Dam, 7.1 <0.05 <0.05 <0.05 0.17

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7.15 Mirrool Creek Study, Oct-Dec 1994

Work carried out by: CSIRO, Division of Water Resources, Griffith, for the NSW DWR.Date of study: 5/10/94 to 30/11/94Location and frequency ofmonitoring:

Murrumbidgee Irrigation Area. Drainage water in Little Mirrool Creek andMirrool Creek at McNamara Rd (just above Willow Dam), and supply waterat the Gogeldrie Supply Branch. Drainage water samples were dailycomposites (100ml every 30 minutes), and supply water was a daily grabsample.

Measurements taken GC-MS quantitative analysis for the following compounds; diuron,molinate, trifluralin, atrazine, bromacil, thiobencarb, malathion,metolachlor, chlorpyrifos, endosulfan, cypermethrin.

GC-MS qualitative screening for methomyl, monocrotophos, simazine,terbufos, diazinon, propanil, methidathion, profenofos, fluazifop-p-butyl,lambda-cyhalothrin, deltamethrin.

Toxicity tests using Ceriodaphnia sp.Method of measurement GC-MS at CSIRO Griffith labReference: - Korth et al (1995a)


Of the 24 pesticides monitored during the study period, ten (molinate, malathion, chlorpyrifos,thiobencarb, endosulfan, diuron, atrazine, metolachlor, simazine, and diazinon) were detected on aregular basis (see Figures 13-28). Four of those pesticides (molinate, chlorpyrifos, malathion, andendosulfan) frequently exceeded either ANZECC ecosystem or EPA interim environmental waterquality guidelines. For example, proportions of the 57 day monitoring period showing environmentalguideline exceedances for Little Mirrool Creek and Mirrool Creek respectively, were as follows:

• molinate 95% and 70%;• chlorpyrifos 63% and 70%,• malathion 35% and 23%;• endosulfans 79% and 81%.

Furthermore, three pesticides (molinate, chlorpyrifos and malathion) often exceeded the proposed EPAnotification and action levels as well. Molinate also exceeded drinking water guidelines for most of themonitoring period at both Little Mirrool Creek and Mirrool Creek.

Drainage water quality fluctuated considerably in terms of pesticide composition during the monitoringperiod. For example, chlorpyrifos and malathion were detected in short (one or two day) pulses whilemolinate, endosulfan and diuron were present for most of the monitoring period. A monitoring regimebased on the use of autosamplers and a frequency between 2 and 8 days was determined to be theminimum required to obtain a reasonably accurate reflection of drainage water pesticide contamination.

The drainage water was found to be toxic to the Australian cladoceran (Ceriodaphnia sp.) on sixoccasions at Little Mirrool Creek and on three occasions at McNamara Rd, Mirrool Creek. (Note;cladocerans (or waterfleas) are important components of the aquatic food web. They graze on algaeand other microorganisms and are consumed by larger predators (eg fish). They are part of theaquatic ecosystem that water quality guidelines are designed to protect and are known to be sensitiveand reliable test organisms which provide an indication of water toxicity to aquatic life.) The toxicevents were found to be chronic in nature (due to greater than 48 hour exposure) and were linked to thepresence of chlorpyrifos and malathion in the drainage water. One of the toxic periods observed inMirrool Creek (day 35) occurred during a period of high drainage flow which coincided with highconcentrations of pesticides.

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Chemical loads leaving the catchment (when calculated for rice pesticides), were found to be <0.5% ofthe total amount applied to the rice crop. Although this is a small percentage, the concentrations weresufficient to cause toxicity to aquatic organisms.

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Figure 13 Average daily molinate concentrations detected at Little Mirrool Creek during monitoringperiod (5 October to 30 November 1994)

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Figure 14 Average daily molinate concentrations detected at Mirrool Creek at McNamara Rd duringmonitoring period (5 October to 30 November 1994)

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Figure 15 Average daily malathion concentrations detected at Little Mirrool Creek during monitoringperiod (5 October to 30 November 1994)

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Figure 16 Average daily malathion concentrations detected at Mirrool Creek at McNamara Rd duringmonitoring period (5 October to 30 November 1994)

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Figure 17 Average daily chlorpyrifos concentrations detected at Little Mirrool Creek during monitoringperiod (5 October to 30 November 1994)

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Figure 18 Average daily chlorpyrifos concentrations detected at Mirrool Creek at McNamara Rdduring monitoring period (5 October to 30 November 1994)

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Figure 19 Average daily thiobencarb concentrations detected at Little Mirrool Creek during monitoringperiod (5 October to 30 November 1994)

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Figure 20 Average daily thiobencarb concentrations detected at Mirrool Creek at McNamara Rdduring monitoring period (5 October to 30 November 1994)

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Figure 21 Average daily endosulfan concentrations detected at Little Mirrool Creek during monitoringperiod (5 October to 30 November 1994)

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Figure 22 Average daily endosulfan concentrations detected at Mirrool Creek at McNamara Rd duringmonitoring period (5 October to 30 November 1994)

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Figure 23 Average daily diuron concentrations detected at Little Mirrool Creek during monitoringperiod (5 October to 30 November 1994)

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Figure 24 Average daily diuron concentrations detected at Mirrool Creek at McNamara Rd duringmonitoring period (5 October to 30 November 1994)

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Figure 28 Average daily metolachlor concentrations detected at Mirrool Creek at McNamara Rdduring monitoring period (5 October to 30 November 1994)

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7.16 The impact of pesticides used in rice agriculture on larvalchironomid morphology

Work carried out by: CSIRO, Division of Water Resources, Griffith.Date of study: Nov 1991 to Mar 1992.Location and frequency ofmonitoring:

Murrumbidgee Irrigation Area. 2 rice bays 10 km south of Griffith wereselected for testing.

Measurements taken Water samples were analysed for molinate, malathion and chlorpyrifosChironomid larvae collected with 300 um hand net at weekly intervals for14 weeks, and inspected for structural abnormalities

Method of measurement Water samples were analysed by GC-MS at CSIRO Griffith labReference: Pettigrove et al. (1995)

Two insecticides, (malathion and chlorpyrifos) and two herbicides (molinate and bensulfuron) wereapplied to two rice fields and their impact on larval chironomid morphology was determined. Nochironomids or other macroinvertebrates survived the application of these pesticides onto the rice bays.A total of 17 chironomid taxa colonised the bays within 3 months after the pesticide applications.Structural abnormalities were detected in fourth instars of Polypedilum nubifer (42%), DicrotendipesSWL sp.1 (34%), Chironomous februarius (20%) and Procladius paludicola (23%) that werecollected from the rice bays. The frequency of abnormalities in the P nubifer, Dicrotendipes SWL sp.1,and P paludicola (but not C februarius) populations in the rice bays were significantly higher than inpopulations collected from reference sites. No structural abnormalities were detected in Larsia albicepslarvae collected from the bays, therefore some larvae may be better indicators of pesticidecontamination than others.

7.17 Groundwater Contamination

The Australian Geological Survey Organisation (AGSO) is conducting a survey of groundwater qualitythroughout Australia, including catchments within the Murray-Darling Basin (Bauld 1995). One of thefirst aquifers to be tested was the shallow groundwater under the irrigation areas near Shepparton,Victoria, and atrazine or simazine was detected in 50% of observation wells (Bauld et al. 1992).Similar results have been observed in other countries, with the triazine herbicides (such as atrazine andsimazine) being most often detected (Ritter 1990, Hallberg 1989, Kuhnt & Franzle 1993, NationalResearch Council of USA 1986, Lees and McVeigh 1988).

The AGSO has also conducted some initial testing of shallow groundwater (0.9 - 7.1 metre depth) inthe Berriquin and Denimein Irrigation Districts (Bauld et al. 1995). Pesticide compounds were detectedin 5/16 bores, although the concentrations were very low. Desethylatrazine (DEA), a metabolite of thetriazine herbicide atrazine, was present in three samples although the parent compound was notdetectable. Other compounds detected were the herbicides simetryn and trifluralin. Further testing ofthe Wakool, Deniboota, Berriquin and Denimein Irrigation Districts is planned for 1995-96.

No monitoring of pesticide concentrations in the deep aquifer near Darlington Point appears to havebeen undertaken although it is unlikely that contamination would have occurred due to its depth (150metres) and the overlying layers of clay (J Bauld, AGSO, Canberra, pers. comm. 1994). Ifcontamination does occur, the most likely pathway is through a disused borehole.

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7.18 Pesticide concentrations in soil.

The pesticides most likely to persist in soil are the organochlorines since they not only attach strongly tosoil particles but also have very long half-lives. Most of these pesticides however, have not been usedfor 10-15 years and are no longer registered for agricultural use.

Residues of organochlorine pesticides such as DDT and dieldrin were detected in soil samples takenfrom irrigation areas in the late 1970s and early 1980s (Hill and Nicholson 1992). More recentmonitoring indicates that these concentrations are declining, although work by Davies (1992) indicatesthat trace levels are still present. Davies analysed sediments from Barren Box Swamp, Yanco MainDrain, Cooragool Lagoon, and three rice farms. Alpha-BHC, Dieldrin DDE and DDD were detected inone or more of the soil samples from rice farms, with the highest concentration being 0.136 mg/kg ofDDE (Table 26). Sediment samples from Yanco Main Drain and Cooragool Lagoon contained tracesof DDE, DDD and DDT but not alpha-BHC or dieldrin (Table 27). Although Davies did not detectorganochlorine residues in sediment from Barren Box Swamp, Garbin (1992), in a separate set ofmeasurements, detected trace levels of DDT residues in both sediment and biota.

Two organochlorines which are still registered for agricultural use are endosulfan and dicofol. Residuesof these pesticides might be detected in soil on farms where large quantities have been used in recentyears. Other pesticides, such as diuron or atrazine, which are directly applied to the soil and haverelatively long half lives (of a couple of months or more), will also be detected in soil at the site ofapplication for up to one year (or more).

Contamination of soil might also have occurred near the sites of old sheep and cattle dips, and alsoaround sheds where pesticide drums have been stored. Soil contamination might also be detected nearsites where pesticide drums have been disposed of.

Table 26 Organochlorine pesticide residues in soils on rice farms of the MIA (mg/kg)sample name αα BHC Dieldrin DDE DDD DDTFlanagan 1 0.024 n.d. 0.017 n.d. n.d.Flanagan 2 0.020 n.d. 0.024 n.d. n.d.Flanagan 3 0.037 n.d. 0.045 n.d. n.d.Little 1 0.047 0.005 0.018 0.021 n.d.Little 2 0.030 n.d. 0.014 0.024 n.d.Little 3 0.019 0.008 0.012 0.023 n.d.Barker 1 0.024 n.d. 0.136 0.048 n.d.Barker 2 0.021 n.d. 0.115 0.049 n.d.Barker 3 0.022 n.d. 0.101 0.052 n.d.

Note 1: Data obtained from Davies (1992).

Table 27 Organochlorine pesticide residues in sediments from the MIA (mg/kg)sample name αα BHC DDE DDD DDTYanco main drain 1 n.d. 0.002 0.001 0.002Yanco main drain 2 n.d. 0.003 0.001 0.002Yanco main drain 3 n.d. n.d. n.d. n.d.Cooragool Lagoon 1 n.d. 0.008 0.004 0.009Cooragool Lagoon 2 n.d. 0.023 0.009 n.d.Cooragool Lagoon 3 n.d. 0.015 0.005 n.d.Barren Box Swamp 1 n.d. n.d. n.d. n.d.Barren Box Swamp 2 n.d. n.d. n.d. n.d.Barren Box Swamp 3 n.d. n.d. n.d. n.d.

Note 1: Data obtained from Davies (1992).Note 2: Although no organochlorine pesticide residues were detected at Barren Box Swamp, three major

unidentified peaks were recorded.

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7.19 Pesticide concentrations in biota.

As discussed in Section 4.5, some pesticides tend to bioaccumulate in aquatic organisms. Thesepesticides are generally lipophilic (accumulate in fat tissue) and are also relatively stable. Theorganochlorine pesticides have a strong tendency for bioaccumulation and were detected in fish duringthe 1970s and early 1980s. Scribner et al. (1987) reported studies carried out in the MurrumbidgeeIrrigation Area during 1974-75 in which 9% of fish sampled contained DDT and 15% containeddieldrin. Since the removal of most organochlorines from agriculture in the early 1980s, concentrationshave fallen dramatically, and studies by Hill & Nicholson (1992) show that pesticide concentrations infish from the Murray River are now extremely low. Garbin (1992) also detected trace levels of DDTresidues in biota from Barren Box Swamp, but these were generally well below MRLs set by the NSWDepartment of Health.

However, fish caught from waterways which are immediately next to fields or orchards wherepesticides are currently being used, might contain trace levels of some pesticides. Nowak and Julli(1991) reported residues of endosulfan in nearly all the fish they sampled from the cotton growing areasof northern NSW.

Some of the pyrethroids (such as cypermethrin and deltamethrin) have also been detected in a smallpercentage of fish samples tested in the Australian Market Basket Survey (NHMRC, 1987). Theorganophosphate, chlorpyrifos is another pesticide which is lipophilic and could potentially accumulatein fish, although its relatively short half life is a mitigating factor. Most other groups of pesticides areless likely to accumulate in fish unless they are exposed to high concentrations.

Although there are no recent studies of pesticide residues in fish caught from irrigation drains in theMIA, CIA and Murray Valley, work in Northern NSW (Nowak and Julli, 1991) coupled with aknowledge of the pesticide concentrations in drainage water, would indicate that there is a highprobability that some pesticides (such as endosulfan) would be detected in the fish flesh. There havealso been no recent studies of pesticide residues in other aquatic fauna (such as frogs and waterfowl)which live or feed in irrigation drains of the MIA, CIA and Murray Valley.

7.20 Surveys of pesticide residues in food

The Australian Market Basket Survey

The Australian Market Basket Survey is conducted every two years and analyses a range of foods forthe presence of pesticides and other contaminants (National Food Authority 1992). Total dietaryintakes of each contaminant are estimated and then compared with the Acceptable Daily Intake (ADI)which is recommended by the World Health Organisation. Some of the pesticides detected in the 1992survey are summarised below and in Table 28;

• DDT was detected in 2 samples and DDE in 14 samples out of a total of 26 samples of human milktested for organochlorines. In all previous years, low levels of pesticides, in particular DDE havebeen found in every sample of human milk tested.

• Organochlorine residues detected in food included endosulfan, DDT, DDE, dicofol and dieldrin.

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• Fenitrothion, an organophosphorus pesticide, is one of the most commonly found pesticides in food.It is used in silos to protect wheat and other cereals from insect pests. Other organophosphatescommonly detected include parathion, chlorpyrifos and malathion.

• The estimated daily intakes of pyrethroids is very low compared with those for other insecticides.

Only three pyrethroids were detected, permethrin, cypermethrin, and fenvalerate. • No herbicide residues were detected in the foods surveyed.

• All samples analysed were within maximum residue limits (MRL) with exception of one sample ofgrapes, which had a chlorpyrifos residue of 0.02 mg/kg (the MRL for grapes is 0.01 mg/kg), andtwo samples of pears which had chlorpyrifos residues of 0.23 mg/kg and 0.22 mg/kg respectively(the MRL for pears is 0.20 mg/kg).

Table 28 Pesticides detected in selected fruit, vegetables and cereals during the 1992 Australian MarketBasket Survey.food pesticides detectedbeans - green DDE, dicloran, dieldrin, dithiocarbamates, endosulfan, heptachlor, permethrin.bread - white chlorpyrifos, chlorpyrifos methyl, fenitrothion, mevinphos, parathion methyl,

pirimiphos methylcarrots chlorthalonil, DDE, dieldrin, endosulfan sulphatecelery chlorfenvinphos, chlorthalonil, chlorpyrifos methyl, dithiocarbamates, endosulfan,

fenvalerate, malathion, methamidophos, parathion, parathion methyl, permethrin,vinclozolin.

grapes chlorpyrifos, dicofol, dithiocarbamates, monocrotophos.lettuce chlorthalonil, dichlorvos, dithiocarbamates, endosulfan, methamidophos,

parathion, vinclozolin.orange juice fenitrothion, malathion, mevinphos, parathion, parathion methyl.potatoes dicloran, dieldrinpumpkin chlorpyrifos, dieldrin, malathion.rice - brown chlorpyrifos-methyl, fenitrothion, parathion methyl, pirimiphos methyl.tomatoes chlorpyrifos, cypermethrin, dicloran, dicofol, dieldrin, dithiocarbamates,

endosulfan, fenvalerate, permethrin, vinclozolin.

National Residue Survey

The Bureau of Resource Sciences supervises the National Residue Survey which is a program formonitoring chemical residues and other contaminants in Australia’s exports of agricultural produce andfood commodities. This survey concentrates on two types of food;• meat, eggs and dairy products,• grain and grain products.

Monitoring pesticide residues in fresh fruit and vegetables by the NSW Department ofAgriculture.

The objectives of this monitoring program are:• to sample fresh fruit and vegetables sold at the Sydney Markets and analyse them for a range of

pesticide residues;• to trace back to the grower any sample which is found to contain unacceptable pesticide residues;• to take appropriate advisory or regulatory actions to ensure excessive residues do not recur; and

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• to provide information on pesticide residues in fresh fruit and vegetables.

Each week a selection of 10 fruit and vegetable samples are bought at the markets. This producecomes from all over NSW as well as interstate. Samples of the produce are analysed for up to 24pesticides. If a sample exceeds the Maximum Residue Limit (MRL), it is traced back to the grower todetermine the cause, and fines can be imposed. Samples grown in NSW are also traced back to thegrower when a residue exceeds 50% of the MRL, to provide advice on improved methods of pesticideapplication.

Results for 1989-1992 survey;• 423 fruit and 1086 vegetable samples were analysed and 98.3% contained either no detectable

residues or residues within the legal limits.• 25 samples contained a residues which exceeded the MRL. 15 of these were technical breaches in

which low residues of a chemical were detected on a crop for which it is not registered.• Eight samples exceeded the MRL for endosulfan (on chinese cabbage, lettuce and onion) and two

exceeded the MRL for chlorpyrifos (on carrot and pear).

Results for the 1992-1994 survey;• 390 fruit and 667 vegetable samples were analysed and 98.9% contained either no detectable

residues or residues within the legal limits.• Twelve samples contained a pesticide residue which exceeded the MRL. Seven of these were

technical breaches in which residues of a chemical were detected on a crop for which it is notregistered.

• Five samples exceeded the MRL on crops for which they were registered. These were forchlorpyrifos in capsicum and tomatoes (2 breaches), fenthion in peach, and parathion in peach.

Further information on these surveys can be obtained from NSW Agriculture Agnotes H1.4.4, (June1993) and DPI/91, (January 1995)..

7.21 Monitoring pesticide residues in drinking water

The NSW Department of Health (Division of Analytical Laboratories) routinely monitored the qualityof drinking water from rural public water supplies (Graham Cook, Division of Analytical Laboratories,pers. comm.). Samples were tested microbiologically for indicator organisms and chemically for a widerange of parameters including agricultural chemical residues. The Public Health Units in each regionof the state collected samples on an annual basis. The sampling date for some of the water supplies inthe irrigation areas of S-W NSW are provided in Appendix C. The chemical substances which weretested for on a routine basis are also presented in Appendix C.

It is worth noting that molinate (a rice herbicide) was not tested for in drinking water despite it beingthe most frequently detected pesticide in drainage water, and has also been detected (on two occasions)in irrigation supply water for the Murray Valley. Molinate is often applied by aerial spraying andspray drift could potentially contaminate the main channels supplying water to towns in the ricegrowing districts. Atrazine and diuron, which are commonly used in the irrigation areas and frequentlydetected in surface waters, were also not tested for on a routine basis. It is also worth noting that mostof the towns in the irrigation areas were not sampled in the months of September-December which iswhen contamination is most likely to occur due to aerial spraying operations. The Leeton and Griffithwater supplies for instance were sampled in June and March respectively.

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7.22 Cholinesterase levels in farmers of the MIA.

From 1983 until 1990, voluntary testing of farmers in the MIA was conducted to check for healtheffects caused by exposure to organophosphate or carbamate pesticides. Recent exposure (in the 3 to 4weeks prior to testing) to these pesticides can affect the amount of the enzyme cholinesterase that ispresent in the blood. The primary aim of the tests was to educate farmers in better handling procedureswith pesticides. If a farmer had a low cholinesterase level, the Community Health Workers wouldprovide advice on how to reduce the risk of exposure (such as wearing protective clothing).

There were however a number of problems with this testing program and these are outlined below;• Testing was only carried out in January -February. Preferably it should have occurred between

October-February as many farmers use organophosphate pesticides in late spring and earlysummer.

• There was not alot of correlation between low cholinesterase levels and poor handling proceduresby farmers (such as not wearing protective clothing), and hence the tests tend to give the farmersthe wrong message.

• If farmers had been exposed to pesticides other than organophosphates or carbamates, theircholinesterase levels would not be depressed, and hence they assumed there was no health risk andwould continue with poor handling practices.

Further details of the testing program are kept by the Community Health Centre in Griffith and resultsof the 1992-93 monitoring are reported by McMullen et al. (1993).

7.23 Other uses of agricultural pesticides

The largest quantities of pesticides used in the irrigation areas are applied to crops for the control ofweeds, insects etc. However another use of pesticides is for the control of pests which attack livestockincluding the treatment of gastro-intestinal worms in sheep (Schumann 1993, Davidson 1985a,b) andcattle (Costantoura 1986), and lice control in sheep (Taylor 1995). A range of chemicals have beenused to treat livestock, including DDT, organophosphates and synthetic pyrethroids, although many ofthese are no longer registered for use, or are ineffective due to increasing resistance.

There have not been any studies in the irrigation areas, which have specifically investigated potentialcontamination of the environment from chemicals used on livestock. Southcott (1980) howeverreported that the chemicals used as drenches are excreted in the animals’ faeces and urine and cancause low levels of contamination in paddocks, especially under heavy stocking rates. Contaminationcan also occur in small isolated areas where the chemicals are applied to the livestock. Traces oforganochlorine residues are still detected in soils surrounding sheep and cattle dips from the use of thesechemicals over 15 years ago.

At present, most research and monitoring of chemicals used on livestock is concentrating on theproblem of residues contaminating the meat (ASTEC 1989, BRS 1994).

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7.24 Other pesticide studies by the CSIRO Laboratory in Griffith

A list of other pesticide research (prior to 1995) that was published by the Griffith Laboratory of theCSIRO Division of Water Resources, is provided below.

Project Overview• Agricultural chemicals contaminating our waterways? by Kim Jenkins, Rural Research No. 168

Spring 1995, pp9-12.

Atrazine• “Atrazine persistence and toxicity in two irrigated soils of Australia” by K H Bowmer, Australian

Journal of Soil Research, 1991, vol 29, pages 339-350.

Dichlobenil• “Residues of dichlobenil in irrigation water” by K H Bowmer, E M O’Loughlin, K Shaw and G R

Sainty, Journal of Environmental Quality, 1976, vol 5 no. 3, pages 315-319.

Diuron• “Residues of diuron and phytotoxic degradation products in aquatic situations. I. Analytical

methods for soil and water” by K H Bowmer and J A Adeney, Pesticide Science, 1978, vol 9, 342-353.

• “Residues of diuron and phytotoxic degradation products in aquatic situations, part II,.- diuron inirrigation water” by K H Bowmer and J A Adeney, Pesticide Science, 1978, vol 9, pages 354-364.

• “Checking out a herbicide in irrigation water” by Bill Sheldon, Rural Research No. 105, Dec1979, pp14-17.

Dalapon & TCA• “Residues of dalapon and TCA in sediments and irrigation water”, by K H Bowmer, Pesticide

Science, 1987, vol 18, pages 1-13.

Glyphosate• “Residues of glyphosate in irrigation water”, by K H Bowmer, Pesticide Science, 1982, vol 13,

pages 623-638.• “Glyphosate-sediment interactions and phytotoxicity in turbid water” by K H Bowmer, M D

Boulton, D L Short and M L Higgins, Pesticide Science, 1986, vol 17, pages 79-88.• “Effect of glyphosate (Roundup) on citrus”, by K H Bowmer and G McCorkelle, Farmers

Newsletter (Irrigation Research and Extension Committee, Griffith) Horticulture No. 165, April1988, p21

Acrolein• “Some aspects of the persistence and fate of acrolein herbicide in water” by K H Bowmer and M L

Higgins, Archives of Environmental Contamination and Toxicology, (1976) Vol 5, pages 87-96.• “The use of acrolein treated water in rice”, by K H Bowmer, W A Muirhead, G McCorkelle, J

Lockhart, J Bonaventura, L Erskine, W Korth and V Naumovski, Farmers Newsletter (IrrigationResearch and Extension Committee, Griffith) Large Area No. 131, April 1988, p21.

• “The acrolein review. Use safety and environmental implications.”, by K H Bowmer and G RSainty, volume 1 is 55 pages of text, volume 2 is appendices. August 1990.

• “Herbicides for injection into flowing water: acrolein and endothal-amine” by K H Bowmer and GH Smith, Weed Research, 1984, vol 24, pages 210-211.

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On-farm recycling and contaminant breakdown.• “On-farm water recycling and herbicide residues”, by K H Bowmer and P G Weerts, Australian

Water Resources Council Research Project 84/163, 1987, 59pp.• “On-farm recycling of irrigation water.” by P G Weerts and K H Bowmer, ANCID Bulletin, Vol

13, June 1987, pp21-28.• “On-farm recycling of drainage water.” by P.G Weerts, K.H. Bowmer & W Korth, Farmers

Newsletter (Irrigation Research and Extension Committee, Griffith) Large Area No. 128, 1986,pp25-27.

• “Contaminant breakdown on farms.” In ‘Practical drainage management and the environment’Workshop Proceedings, Michengowrie near Boggabri, 18 Nov 1992, Irrigation Association ofAustralia, 10pp.

• “Eliminating on-farm contamination.” the Australian Cottongrower, Vol 14, No 2, pages 44-47.

Aquaculture• “Aquaculture and pesticides in the NSW Riverina” by K H Bowmer, J Roberts, A Scott, G Napier

and W Korth., published by the NSW Office of Labour Market Adjustment, Aquaculture Fishing& related Industries Committee, 1994, 45 pages (CSIRO Division of Water ResourcesConsultancy Report No. 94/17).

Ecotoxicology• “Rapid biological assay and limitations in macrophyte ecotoxicology: a review” by K H Bowmer,

Australian Journal of Marine and Freshwater Research, 1986, vol 37, pages 297-308.• “Selection of a suitable cladoceran species for toxicity testing in turbid waters”, by L Anderson-

Carnahan et al., Australian Journal of Ecology, 1995, vol 20, pages 28-33.

• “Development of methods for culturing and conducting aquatic toxicity tests with the Australiancladoceran Moina australiensis”. by L Anderson-Carnahan, CSIRO Division of Water Resources,Water Resources Series No. 13, 1994, 56pp.

Immunoassay• Development and application of laboratory and field immunoassays for chlorpyrifos in water and

soil matrices. by A S Hill et al. Journal of Agricultural and Food Chemistry, 1994, vol 42, pages2051-2058.

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8 REDUCING THE IMPACT OF PESTICIDES

Much can be done through the adoption of best management practices to minimise drainage volumesand chemical loads leaving individual farms and also to prevent drainage water from reaching naturalwaterbodies. Many agricultural industries have already adopted best management practices and havesignificantly reduced pesticide loads entering rivers.

A variety of on-farm and regional practices are discussed in the following sections.

8.1 More efficient use of pesticides

Correct use of pesticides will not only result in more effective pest control but will also reduce the riskof environmental contamination. This includes the following practices.

Choosing the most effective pesticide for the weed or insect being targeted.Poor choice of pesticides results in large quantities or repeated doses being used with little impact onthe target species. Choosing the correct pesticide will result in improved crop yields, more efficient useand less entering drainage systems.

Using the recommended rate of application.Using the application rate specified on the label will provide the most effective and most economic pestmanagement. Application at higher rates simply results in increased costs, greater risk ofenvironmental contamination, and rarely give better results.

Timing of applicationFor effective control of weeds or insects, many pesticides need to be applied at a critical time in theseason (in order to attack the target pest at its most vulnerable stage in growth). Application at thecorrect time will provide the best results and decrease the need for further pesticide use.

Careful monitoring for threshold damage levels from insect pests will not only minimise the damagecaused to the crop, but will also eliminate unnecessary use of insecticides.

Only apply pesticides if the weather is suitable.Some herbicides will wash off plant surfaces if applied just before rain, whilst others are not affected orneed some rain to incorporate and activate them. Therefore it is critical that instructions on labels thatrelate to the weather are read before the pesticide is applied.

No pesticides should be applied in high winds as there will be serious spray drift. Extremely hot daysshould also be avoided since much of the pesticide might be lost through volatilisation.

Avoid spray drift and overspraying of drains.Spray drift not only poses risks to the environment and neighbouring communities but can also causedamage to nearby crops.

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The following methods will minimise the risk of spray drift:

• Spraying should not occur during high winds. Ideally there should be a light breeze (4-10 km/hr)and stable atmospheric conditions (ie when there is no atmospheric inversion layer). A light breezeprevents clouds of ‘spray fog’ drifting and aids penetration of spray through the plant canopy.

• Drift of pesticides is also strongly dependent on the size of droplets formed during application. To

minimise drift and still achieve uniform distribution, the recommended spray pressure and nozzlesize should be used. Control the spray volume by changing nozzles, NOT by varying pressure, as ahigher pressure creates a finer spray and increases the chance of spray drift. Ensure sprayequipment is clean and in good working order, and maintain the correct height above the target toensure good coverage.

• Spraying should be confined to times when the wind is blowing away from sensitive areas such assupply channels, drains and public roads.

When using aircraft, drift can be reduced by spraying with the wind, and overspraying is

eliminated by cutting off early before crossing channels. • To avoid overspray, incorporate buffer strips between crops and irrigation channels.

Application methodThe efficiency of spray application can be very low if the correct application methods are not used.Below are some techniques that can increase the efficiency and reduce off-target losses.

• Herbicide application on fallow paddocks can use a boom spray fitted with electronic sensors sothat spraying only occurs when passing over a weed.

• The use of electrically charged spray droplets that are attracted to plants, is a system commonly

used for spraying grape vines. It reduces considerably the volumes of spray used. • For row crops, ground rigs can be used early in the season, band spraying the rows only.

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• Low volume spray equipment (Controlled Droplet Application) produces very even droplet size andreduces the ‘fines’ that cause drift problems. This equipment also eliminates run-off which occursat high volumes.

Whatever spray task is at hand, there should be a thorough understanding of the equipment available,crop characteristics, chemical formulations and nature of risks that might be present.

8.2 More efficient irrigation techniques

Pesticide and nutrient losses in drainage water can be minimised by increasing irrigation efficiency sothat there is less runoff (tailwater) leaving the field. More efficient irrigation not only reduces theimpact of pesticides and nutrients on the environment but also provides financial benefits by reducinglosses of valuable chemicals from the field.

Surface floodingThe efficiency of surface flooding (either bays or furrows) can be poor if the soil surface is uneven orthe wrong slope. Slow irrigation and poor drainage cause waterlogging and restrict plant growth.Water losses from run-off and deep seepage are often substantial.

However in recent years vast areas of irrigation land have been laser levelled. This is extremelyaccurate and produces flat regular shaped fields that water quickly and evenly. Much greater efficiencyof irrigation is now possible.

With furrow irrigation, excessive application of water often occurs at the head of the furrow in order tohave adequate application towards the far end. This can result in waterlogging and a high level ofseepage losses (with associated chemicals) at the head of furrows. Using primary and secondary flows,or surge flows, helps move the water quickly along the furrow and can improve the uniformity of waterapplication and reduce seepage.

Low pressure drip and micro-irrigationSurface flooding systems apply water to the entire soil surface. This can be wasteful for crops such asvines and trees, with root zones restricted to widely spaced, relatively small areas. In drip irrigation ormicro-irrigation (mini ground sprinklers) water is applied to individual plants at low pressure, wettingonly part of the soil surface. These systems can virtually eliminate surface drainage and the associatedloss of pesticides and nutrients, except during large storm events when surface runoff is inevitable.Most new vineyard and orchard developments use these systems because of their high water efficiency,low pressure requirements (compared with the older overhead sprinkler systems), and they can beinstalled over varying terrain at a relatively cheap cost.

Irrigation schedulingWhatever method of irrigation is used, sufficient water needs to be applied without waste, and at thecorrect time, to achieve optimum crop productivity and efficient uses of resources. Over-irrigation canresult in wastage of water through excessive runoff or seepage past the root zone and increasedquantities of nutrients and pesticide residues reaching irrigation drains. Irrigation scheduling can helpovercome these problems by enabling irrigators to determine when and how much water needs to beapplied to meet crop requirements. Irrigation requirements are determined by water holding capacity ofthe soil and losses of water to the atmosphere from the soil and crop (evapo-transpiration). Methodsused to estimate the soil moisture content range from simple subjective assessments to the use ofspecialised instruments and computers.

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8.3 On-farm water re-use schemes

Water re-use schemes can greatly reduce (or eliminate) the amount of drainage water, and associatedcontaminants, leaving irrigated farms. The simplest form of water re-use is the diversion of drainagewater to irrigate further crops or pasture. Other schemes consist of an enlarged drainage sump whichcan be pumped out into adjacent supply channels. This type of scheme is typical of irrigated pastureareas in northern Victoria. In other areas, drainage can be pumped into dams where it is stored for latergravity diversion and shandying with supply water. Some systems use the recirculation channel as astorage.

Cotton enterprises in northern NSW are required to retain all irrigation drainage and most storm runoffon their properties (see Figure 29). Similar requirements are being introduced in other regions.

Figure 29. Typical irrigated cotton farm with tailwater re-use system (from Barrett et al. (1991)

Issues that need to be considered before installing a recycling system are:

• The salinity of the recycled water and whether it needs to be mixed with fresh supply water beforeapplying it to crops.

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• Whether there are any contaminants present, such as pesticides (atrazine for example) or plantpests (such as nematodes), that might damage crops irrigated with recycled water. The effects ofpoor water quality in re-use schemes can often be reduced by careful irrigation management andalso by shandying the drainage water with high quality supply water.

• What the optimum design is (in terms of farm layout) and the associated cost of setting up a

recycling system, including the need for new pumps, and a storage dam. It is worth noting that astorage dam can provide added flexibility of operation and also allows runoff from storms to becollected.

Further information on drainage water re-use are provided by NSW Agriculture (1992) and Bowmer &Weerts (1987).

8.4 Whole farm planning

A whole farm plan is essential to maximise the effectiveness of irrigation techniques, irrigationscheduling, and drainage water re-use schemes. The preparation of whole farm plans and the designand installation of irrigation layouts have become highly skilled procedures. Consultants are usuallyengaged to prepare and implement these plans with active participation and input from the farmer. Thedesigns are usually planned to enable staging of the installation. It can therefore be done whenaffordable. Productivity and efficiency gains can be considerable.

8.5 Alternative pest management methods

There is growing awareness within the farming community that alternatives to pesticides are availablefor the management of pests. This approach often makes good economic sense since it can reduce theneed for expensive chemical applications. In addition, produce can be marketed as containing lesschemicals and may command a premium price. Many agricultural industries are actively reducing theirpesticide use, some very successfully (eg. stonefruit and grapes).

Some alternative pest management methods are described below:

• Crop rotation - This reduces the risk of pests multiplying to damaging levels by breaking diseaseand breeding cycles, and continues to be a widely used method of controlling pests in row andbroad acre cropping.

• Biological control - The encouragement of natural predators that consume the pest, has been

successfully implemented for a number of crops. One example is the control of mites on stonefruitthrough the use of predator mites. A similar strategy is being developed for the control of mites ongrapevines (James & Whitney, 1995). However in some instances the population of predators lagsbehind that of the pest, and significant damage to the crop might still occur. This problem can beovercome by releasing large numbers of predators when they are required. Parasitic wasps areregularly released by citrus growers to control scale insects. Another method of biological controlis the use of sprays incorporating bacteria, viruses or insect hormones, which act on the pestspecies. An example of this is the use of the bacteria Bacillus thuringiensis which is widely usedas an insecticide on many horticultural crops. Genetic engineering of pest resistant crops is alsoshowing a great deal of promise.

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Soft chemical alternatives - Examples include the use of white oil for control of pests on citrus,and the use of sulphur compounds for the control of powdery mildew on grape vines. Theseproducts have a narrow spectrum of activity and are more desirable than broad spectruminsecticides, since they only kill the target pest and do not harm predatory insects or otherbeneficial insects (such as bees).

• Integrated pest management - This is a strategy for low chemical use, and relies on determining

when pest control is necessary rather than applying pesticides at regular intervals as a preventativemeasure. It also uses other management practices to help reduce pest problems. For example, thegeneration of dust promotes mite and scale populations in orchards. These pests can therefore becontrolled without the use of chemicals simply by eliminating cultivation of the soil between therows and using mowed pasture swards instead. The use of soft chemicals, biological control andcrop rotation all form part of an integrated pest management strategy.

8.6 Handling and disposal of pesticides

Best Management Practices have been developed that ensure pesticides are handled and disposed of in amanner that is neither dangerous to the operator or the environment. They include the following points:

• Amnesty days should be declared by local authorities for the collection of unused chemicals toprevent disposal that may contaminate waterways or sterilise areas on farms.

• Tanks should never be rinsed out near drainage or supply channels, and any remaining chemicalshould be sprayed onto crops.

• When preparing chemicals, the empty pesticide container should be rinsed, and the rinse watertipped into the spray tank. The rinsings should then be sprayed onto the crop and must not bepoured down a drain.

• Empty containers must be disposed of (after rinsing) by taking to a recycling depot or crushing andburying. Never dispose of empty drums in dams, channels or near water.

Guidelines for the disposal of empty farm chemical containers have been developed by Avcare (1995).

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8.7 Regional water re-use schemes

The purpose of regional water re-use schemes is to utilise drainage water before it finally enters awatercourse, thereby reducing the total volume discharged. This already occurs in several parts of theMurray-Darling Basin including the downstream regions of the Murrumbidgee Irrigation Area in NSW,and sections of the Goulburn and Kerang regions of northern Victoria.. Water re-use schemes willbecome increasingly attractive if upstream farmers can reduce the loads of contaminants enteringdrainage water, thus reducing the risk of water quality problems when water is re-used on crops or forstock and domestic purposes by downstream farmers. Pricing of drainage water at a lower rate thangood quality supply water is a good way of encouraging regional water re-use schemes. In some areas,the introduction of a drainage charge is being considered as further incentive to reduce drainagevolumes.

8.8 Vegetation in drains

Long slow flowing vegetated drains are most likely to reduce pesticide and nutrient concentrations.Some chemicals are readily transported by the drainage system (nitrate and soluble herbicides such asatrazine, molinate, metolachlor) and only decrease in concentration over long distances. Othershowever (such as phosphorus and the insecticides chlorpyrifos and malathion) will decrease inconcentration over short distances. In general it is the hydrophobic chemicals which are most easilyremoved through adsorption to sediment particles and surfaces of aquatic plants, whilst the soluble(hydrophilic) chemicals remain in solution and move down the drain.

Although vegetated drains appear to remove pesticides more efficiently than unvegetated drains, thereare operational problems with having large amounts of vegetation in drains. These include a restrictionin drainage flow and increased problems with mosquito breeding. In rice areas, vegetation in drains canalso be a source of aquatic weeds that could spread into the rice bays.

8.9 Constructed and managed wetlands

Wetlands can be utilised as biological filters to remove or immobilise nutrients and other contaminantsfrom agricultural run-off. However, mechanisms for the removal of nutrients and contaminants are notfully understood and removal rates can vary widely from poor to high. There is also some debate aboutthe long term effectiveness of large regional constructed wetlands, and there are potential problems withaccessions to groundwater.

Small constructed wetlands on individual farms may be of some benefit for contaminant reduction inirrigation drainage. Feasibility will be restricted by availability of suitable flat, low lying land. Ifpumping is required, cost of treatment will escalate.

It has been suggested that natural wetlands should be utilised as biological filters to remove orimmobilise nutrients and other contaminants from agricultural and urban run-off, treated sewage andother sources of effluent. Extreme caution must be exercised when contemplating the use of naturalwetlands in this fashion. The change in flow regime, increases in nutrient loads, and the impact of other

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contaminants such as pesticide residues, can change the natural functioning of the wetland and greatlyreduce its biodiversity.

8.10 Land and Water Management Plans

“Water management must adopt an integrated approach, taking into account a widerange of ecological, economic and social factors ”

Managing water quality in irrigation areas is a big task. This requires a co-ordinated effort over anextended period of time between all levels of governments and all sectors of the local community.Actions must be coordinated both within and across catchments.

Some communities, with assistance from governments, have set up Land & Water Management Plansto tackle the problem. These plans are developed by local communities in partnership with stategovernments, through groups of local stakeholders. Each group analyses and assesses their catchmentto identify and quantify the water quality issues. This leads to a catchment based management plancontaining recommended actions and implementation targets aimed at sustainable land use and reliablewater quality.

Land & Water Management Plans are being developed for each of the three main irrigation areas insouth-western NSW; the MIA, CIA and Murray Valley.

8.11 Maintaining a ‘Clean Green’ image

If the agricultural industries in the irrigation areas of S-W NSW are to expand their markets bothwithin Australia and overseas, it is essential that the region maintains a ‘clean green’ image. Even if aproduct contains levels of pesticides well below the Maximum Residue Limit, the image of the productcan be badly tarnished, and this can have a large impact on market price. Examples of this would bethe 1987 'beef export' crisis when organochlorines were detected in meat exported to the USA; and themajor slump in fish sales in Sydney during 1989 after a report from the Sydney Water Board revealedlow levels of mercury in some fish species caught off Sydney beaches. In 1994, the detection of tracelevels of a cotton pesticide (Helix) in Australian beef caused the suspension of sales to overseasmarkets, and resulted in large financial losses to the cattle industry.

To maintain a ‘clean green’ marketing image, in the irrigation areas of S-W NSW, there needs to be co-ordinated action by growers, government authorities and research institutions to implement effectiveprograms for the reduction of pesticide use.

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9. FUTURE RESEARCH

To determine the full impact of pesticides on aquatic ecosystems in the irrigation areas of S-W NSW,and hence develop better farm practices for the reduction of pesticide contamination, the followingresearch needs to be pursued.

9.1 Alternative pest control methods.

• Development of alternative pest control methods will reduce the need for pesticides. This includes,- integrated pest management strategies,- optimising the rotation of crops,- biological pesticides (such as Bacillus thuringiensis),- soft chemical alternatives (eg white oil on citrus),- research into identifying biological controls (such as the use of predators),- encouraging the use of low chemical regimes and organic farming practices.

• Development of new pest resistant crops to reduce or eliminate the need for pesticides.

9.2 Pesticide monitoring studies

• The impact of pesticides on the major rivers. Most monitoring work has concentrated onmeasuring the concentrations of pesticides in drainage channels within the irrigation areas. Futuremonitoring should also focus on determining the quantities (and resulting ecological impacts) ofpesticides entering the major rivers in the region. The NSW Department of Land & WaterConservation has been undertaking a major river monitoring project in the cotton growing regionsof central and north-west NSW (Cooper 1994, Preece et al. 1993, Cooper 1995). A similarmonitoring program needs to be set up for the Murrumbidgee and Murray Rivers in southern NSW.This program should include both chemical and biological monitoring techniques.

• Studies to investigate the pesticide loads entering waterways during storms. During a major floodof the Mississippi River, USA in 1993, it had been anticipated that the higher streamflows woulddilute the pesticide concentrations that are normally detected. Instead, concentrations were similarto the maximum dry weather concentrations and the total loads considerably higher (Goolsby et al.1993). Similar observations have been made in the cotton growing districts of northern NSW(Preece & Whalley 1993). Monitoring of storm events should be undertaken in the irrigation areasof S-W NSW to determine the quantities of pesticides reaching waterways during high flowconditions. Methods of reducing these loads need to be investigated.

• Pesticides in runoff from dryland farms. There is very little data available on the types andconcentrations of pesticides in surface runoff from dryland farming in the Murrumbidgee andMurray river catchments. However, some initial testing by the NSW Department of Land & WaterConservation (G Carter, NSW DWR, Leeton office, pers. comm.) has detected simazine in theJugiong Creek (0.4 µg/L on 25th May 1995) and both simazine and atrazine in the MurrumbidgeeRiver at Wagga Wagga (0.3 µg/L simazine on 26th May 1995 and 0.2 µg/L atrazine on 6th July1995). Monitoring of runoff from dryland farming should occur during storm events when surfacerunoff (and hence the risk of pesticide contamination) is at its greatest.

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• Crop specific data. Most of the monitoring carried out to date has concentrated on pesticides indrainage water from rice farms and a good understanding of the expected concentrations has beengained. However there has only been a limited number of studies for other crops (such as grapes,citrus and summer crops). Future monitoring should include some projects that target pesticidesused on specific crops (other than rice). This data would help identify any problems of pesticidecontamination associated with a particular crop, and could be used to develop better managementpractices.

• Different irrigation regions. Much of the pesticide monitoring in S-W NSW, and in particular thework undertaken by the CSIRO, has been centred around the MIA. Future monitoring shouldinclude more studies in the Coleambally and Murray Valley Irrigation Areas to help develop a morebalanced perspective of pesticide contamination of all these regions. Practices in these regions canvary and it cannot be assumed that the results from one apply to others.

• Calculation of pesticide loads entering waterbodies , not just concentrations. Monitoring programsshould always endeavour to collect flow data so that the total pesticide loads entering rivers andstreams can be calculated.

• Monitoring of pesticide residues in sediments. Many pesticides are transient in the water column,either because they are rapidly dissipated by chemical or microbial processes, or are adsorbed ontosediments and/or vegetation. There is evidence that sediment uptake of pesticides such asendosulfan may result in protection for organisms in the water column, but raises concerns aboutthe possibility of gradual loading of the system, and risk for benthic organisms. It is recommendedthat general monitoring schemes should examine sediments for pesticide accumulation and theresulting impact on benthic organisms. (Any monitoring of sediment should include a screeningfor the accumulation of metals such as copper and cadmium.) Information on pesticide and metalconcentrations in sediments and soils could be stored on a Geographic Information System (GIS)along with information on the types of cropping, soil types, and the location and types ofwaterways.

9.3 Ecotoxicology and pesticide impact on aquatic food webs.

• Research into the impact of pesticides on the aquatic food webs, including species higher up thefood chain such as frogs, waterfowl and other vertebrates. Other parts of the food web that needfurther study include the impact that herbicide residues have on aquatic plant communities of therivers and lakes in the region. The food web studies should also investigate the long term chroniceffects that low levels of pesticides might have on aquatic ecosystems.

• Impacts of pesticide additives. Very little information is available on the impact that the chemicalsadded to pesticide formulations might be having on aquatic ecosystems in the irrigation areas. Toenable a proper assessment, the monitoring of drainage water for the presence of chemical additivesshould be carried out. If these chemicals are detected, then the concentrations need to be comparedwith toxicity data which is either available in the literature, or can be obtained from laboratorytests.

• Combined effect of multiple chemicals. Most ecotoxicological studies only investigate the impactsof one pesticide at a time. However in reality, aquatic organisms in rivers, lakes and drains areoften being exposed to more than one pesticide, especially during spring and summer when a rangeof herbicides and insecticides are being applied to crops. The combined effect of these chemicalsneeds to be investigated.

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• Further collection of toxicity data for Australian aquatic species, including those found inwaterbodies of south-western NSW. The water quality guidelines for waterbodies in S-W NSWcan then be modified as this data becomes available.

9.4 Analytical techniques

• Immunoassays. One of the major constraints with developing a comprehensive pesticidemonitoring programme, is the very high cost of chemical analysis. The immunoassay techniquesnot only provide a much cheaper alternative but also have the advantage that they can be performedin the field. Further development is needed so that a much wider range of pesticides can be testedusing these techniques.

• Automatic monitoring stations Another area for future research is the development of automaticpesticide monitors which could be placed in waterways and continuously record the pesticideconcentrations of the water. The data could then be transmitted to a central office for assessmentby the local water authority.

9.5 Other issues

• Developing ways to get a strong message across to landholders and commodity groups to changefarming practices. Techniques being used in other countries (such as Sweden, Denmark, theNetherlands and the USA) should be reviewed.

• Investigation of the use of constructed wetlands to filter out pesticides (and nutrients). Constructedwetlands have been considered as a possible method for filtering out pesticides and nutrients fromdrainage water before it enters the main river systems. There are a number of issues relating to theperformance of wetlands that need to be resolved before these systems are built. This includes;optimum design (including size, shape, hydrology, retention time); performance during floods,problems associated with increased groundwater accession, and possible accumulation of chemicalsin sediments.

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Yokoyama T., Saka H., Fujita S. & Nishiuchi Y. (1988) Sensitivity of japanese eel Anguilla japonicato 68 kinds of agricultural chemicals. Bull. Agric. Chem. Insp. Stn. 28:26-33

Information on pesticide use patterns in 1994-95 have been estimated by providing details of;the area of each crop grown, the types of pesticides used for each crop, the standard applicationrates and the typical number of applications per crop.

Apart from the application rates, this information was not readily available and in most casesonly rough estimates could be obtained. For instance, the planted area of a crop can varyrapidly from season to season depending on markets and on-farm factors. The type of pesticideused and the number of applications per crop can vary markedly from farm to farm, and fromseason to season depending on what pests are a problem and also on individual farmerpreferences. The products listed in the following sections are a representative selection of thepesticides most commonly used and was by no means exhaustive. Not all pesticides are appliedin each season, some substitute for each other, and in many cases unlisted alternatives exist.The number of applications of insecticides and fungicides can vary considerably depending onthe season. Herbicides are generally applied once, except for knockdown types which might beused several times in clean-up operations, depending on seasonal growth patterns.

The following lists only provide information on the major crops of the irrigation areas and manyother chemicals would have been used on diverse small crops areas. The MIA in particular isbecoming very diverse and the local spectrum of pesticides in use is changing as the cropschange. The lists presented below are not the complete range of chemicals used on each cropbut provide details of those which were most commonly used. (A selection of useful referenceswhich were used to obtain the following information is presented at the end of the Appendix)

APPENDIX A Details of pesticide use in 1994-95 on a crop by crop basis

Pesticides used for rice growing in 1994-95Chemical Trade name active

ingredientapplication

rate number methodtime ofseason

Herbicidesmolinate Molinate

Ordram960 g/L 3.75 L/ha nearly all crops,

once per seasonaerial,water-run,direct,boom

Oct-Nov

thiobencarb Saturn 800 g/L 3.8 L/ha minor use onceper season,

aerial,water-run,boom

Oct-Nov

bensulfuron-methyl

Londax 600 g/kg 50 g/ha nearly all crops,once per season

aerial Nov

propanil Ronacil 360 g/L 10 L/ha minor use, onceper season

boom Oct

dicamba Banvel 200 g/L 1.4 L/ha very minor use,once per season

aerial,boom Nov

MCPA MCPA 250 g/L 2.8 L/ha minor use, onceper season

aerial Nov-Dec

glyphosate Roundup 450 g/L 1 L/Ha minor use for drillsown rice, onceper season

boom Sept-Oct

paraquat,diquat

Sprayseed 125 g/L,75 g/L

2.8 L/Ha minor use, drillsown rice, onceper season

boom Oct

Insecticidesmalathion Maldison

Maldison1000 g/L 0.3 L/Ha nearly all crops,

once per seasonaerial, seed Oct-Nov

chlorpyrifos Lorsban 500 g/L 0.1 L/Ha nearly all crops, 1-2 sprays/season

aerial Oct-Nov,Feb-Mar

trichlorfon DipterexLepidex

500 g/L 0.8 L/Ha minor use onceper season

aerial Nov,Feb-Mar

Othercoppersulphate

bluestone 25% copper 6-12kg/ha

minor use onceper season,(controlof algae and snails

aerial Oct-Dec

Pesticides used on winter cereal crops (wheat, barley, oats) in 1994-95

Chemical Tradename

activeingredient

applicationrate number method

time ofseason

HerbicidesMCPA amine MCPA 500 g/L 0.7-2.1 L/ha 1 boom,aerial May-Aug2,4-D amine various 500 g/L 0.4-2.1 L/ha 1 boom,aerial Jun-Augdiclofop Hoegrass 375 g/L 1.5-2.0 L/ha 1 boom,aerial May-Julfenoxaprop Puma 60 g/L 0.5-2.0 L/ha 1 boom,aerial May-JulMCPA/diflufenicam

Tigrex 250 g/L,25 g/L

0.5-1.0 L/ha 1 boom,aerial May-Jul

Insecticidesfenvalerate Sumicidin 200 g/L 130-330 mL/ha 1 boom,aerial May-Augmethomyl Lannate 225 g/L 1.0-1.5 L/ha 1 boom,aerial May-Augchlorpyrifos Lorsban 500 g/L 0.14-0.3 L/ha 1 boom May-JunFungicidespropiconazole Tilt 250 g/L 0.25-1.0 L/ha 1-2 boom,aerial May-Septtriadimeton Bayleton 125 g/L 0.5-1.0 L/ha 1-2 boom,aerial May-Sept

Pesticides used on irrigated pasture in 1994-95

Chemical Trade name activeingredient


time ofseason

HerbicidesMCPA MCPA 500 g/L 0.35-2.1 L/ha 1, (common use) boom,aerial all year2,4-D amine various 500 g/L 0.7-4.0 L/ha 1 boom, aerial all year2,4-D ester various 800 g/L 0.7-4.0 L/ha 1 boom, aerial all year2,4-DB various 400 g/L 2.1-4.0 L/ha 1 boom,aerial all yearglyphosate Roundup 450 g/L 0.2-1.4 L/ha 1 boom, aerial all yeardicamba Banvel 200 g/L 0.7-2.8 L/ha 1 boom,aerialparaquat Gramoxone 200 g/L 0.5-1.5 L/ha 1, (common use) boom May-Julfluazifop-p-butyl

Fusilade 212 g/L 1 May-Sep

diquat Reglone 200 g/L 0.7-1.5 L/ha 1, (common use) boom Jun-Julsethoxydim May-Junhaloxyfop May-SepInsecticideschlorpyrifos Lorsban 500 g/L 0.1-1.5 L/ha 1-2 boom,aerial all yeardimethoate Rogor 400 g/L 0.085 L/ha 1-2(common use) boom,aerial Autumn,

Springomethoate Lemat 580 g/L 0.05 L/ha 1-2 boom, aerial Autumn,

Springdemeton-s-methyl

Autumn,spring

fenitrothion Folithion 1000 g/L 0.325 L/ha 1 boom,aerial Spring-summer

monocrotophos Azodrin 400 g/L 0.35-0.7 L/ha 1 boom,aerial Spring-summer

Pesticides used on canola in 1994-95



time ofseason

Herbicidestrifluralin Treflan 400 g/L 1.4-2.1 L/ha 1 boom Apr-Mayfluazifop-p-butyl

Fusilade 212 g/L 0.5 L/ha 1 boom May-Jul

clopyralid Lontrel 300 g/L 0.3 L/ha 1 boom May-JulInsecticideschlorpyrifos Lorsban 500 g/L 0.14-0.3 L/ha 1 boom May-Julendosulfan Endosulfan

Thiodan350 g/L 1.5-3.0 L/ha 1 boom May-Oct

lambda-cyhalothrin

Karate 50 g/L 0.18 L/ha 1 boom Sep-Oct

omethoate LeMat 580 g/L 35 mL/Ha 1-2 boom May-JuLdimethoate Rogor 400 g/L 40-55 mL/ha 1-2 boom May-Julfungicidesnot usuallyneeded

Pesticides used on soybeans in 1994-95



time ofseason

Herbicidestrifluralin Treflan 400 g/L 2.1 L/ha 1 (common) boom Sept-Novsethoxydim Sertin 186 g/L 1.0 L/ha 1 boom Nov-Decfluazifop-p-butyl

Fusilade 212 g/L 0.5-1.0 L/ha 1 boom Nov-Dec

haloxyfop Verdict 104 g/L 1-1.5 L/ha 1 boom Nov-Decimazethapyr Spinnaker 240 g/L 400 ml/ha 1 boom Nov-Decbentazone Basagran 480 g/L 2.0 L/ha 1 (common) boom Nov-DecInsecticidesendosulfan Endosulfan 350 g/L 2.1 L/ha 1-2 (common) aerial,boom Nov-Febmethomyl Lannate 225 g/L 1.5 L/ha 1-2 aeiral,boom Nov-Febcypermethrin Cymbush 250 g/L 0.4 L/ha 1-2 aerial, boom Nov-Febdeltamethrin Decis 250 g/L 0.5 L/ha 1-2 aerial,boom Nov-Feblambda-cyhalothrin

Karate 50 g/L 0.3-0.36L/ha

1-2 aerial,boom Nov-Feb

fungicidesmancozeb various 800 g/kg 2.2 kg/ha 1-2 boom Nov-Feb

Pesticides used on maize and sorghum in 1994-95



time ofseason

Herbicidesmetolachlor/atrazine

Primextra 227 g/L,223 g/L

5.3 L/ha 1 boom Oct-Dec

atrazine various 500 g/L 4.5-6.5 L/ha 1 boom Oct-DecInsecticidesendosulfan Endosulfan 350 g/L 2.1 L/ha 1-2 (commonly

used)aerial Jan-Feb

chlorpyrifos Lorsban 500 g/L 0.5-1.5 L/ha 1 boom Nov-Decmethomyl Lannate 225 g/L 1.5 L/ha 1-2 aeiral Jan-Febcypermethrin Cymbush 250 g/L 0.4 L/ha 1-2 aerial Jan-Febterbufos Counter 150 g/kg 1.7-2 kg/ha 1 boom Oct-Decdeltamethrin Decis 250 g/L 0.5 L/ha 1-2 aerial Jan-Feb

Pesticides used on grapes in 1994-95



time ofseason

Herbicidesglyphosate Roundup 360 g/L 3.0 L/ha,

1 L/100L1-2 (common) boom Aug-Apr

oryzalin Surflan 500 g/L 4.5-6.8 L/ha 1 boom Aug-Septsimazine various 500 g/L 2.3-4.5 L/ha 1 boom Aug-Septfluazifop-p-butyl Fusilade 212 g/L 1.0 L/Ha 1 boom Oct-Maydiuron various 500 g/L 4.5 kg/ha 1 (rarely used) boom Aug-Septparaquat/ diquat Tryquat 100 g/L,

50 g/L2 L/ha 1 boom Aug-Sept

Insecticides (&miticides)carbaryl Carbaryl 500 g/L 0.2 L/100L 2 Air Blast Nov-Marmalathion maldison 500 g/L 0.2 L/100L 2 air blast Nov-MarB. thuringiensis Dipel,

Novosol1600 units 25 g/100L 2 (common) Air blast Nov-Mar

chlorpyrifos Lorsban 500 g/L 0.05 L/100L 2 Air blast Oct-Marpromecarb Carbamult 490 g/kg 100 g/100L 2 Air blast Nov-MarFungicidescopper sulphate Bordeaux

mixture1 kg/100L 2 Air blast Oct-Mar

copperoxychloride

various 500 g/kg 400 g/100L 2 Air blast Oct-Mar

copper hydroxide Kocide 500 g/kg 200-300g/100L

2 Air blast Oct-Mar

mancozeb Dithane 800 g/kg 200 g/100L 4-6 Air blast Sep-Mardithianon Delan 750 g/kg 50 g/100L 2-4 air blast Sep-Mariprodione Rovral 500 g/L 100 g/100L 2? air blast Nov-Marchlorothalonil Bravo 500 g/L 2.6-3.3 L/ha 2 air blast Nov-Marbenomyl Benlate 500 g/kg 100 g/100L 1-2 Air blast Nov-Marsulphur various 800 g/kg 200-300 g

/100L3-4 Air blast Nov-Mar

propiconazole Tilt 250 g/L 10 ml/100L 1-2 Air blast Oct-Febmetalaxyl /copperoxychloride

Ridomil plus 150 g/kg,350 g/kg

150 g/100L 2-3 air blast Oct-Mar

Pesticides used on citrus in 1994-95



time ofseason

Herbicidesdiuron/bromacil Krovar 400 g/kg,

400 g/kg2.2-9.0 kg/ha 1 (very

common use)boom Aug-May

bromacil Hyvar 800 g/kg 2.2-4.5 kg/ha 1 boom Sep-Maydiuron various 500 g/L 4.5 kg/ha 1 boom Sep-Mayglyphosate Roundup 360 g/L 3.0 L/ha,

1 L/100L2-3 boom Aug-May

Insecticidessummer oil various 1-2 L/100L 1-2 (common) air blast Feb-Marmalathion Maldison 500 g/L 0.2 kg/100L 1-2 (minor

use)air blast Nov-Dec

methidathion Supracide 400 g/L 125 ml/100L 1 (minor use) air blast Nov-MarFungicidescopper sulphate Bordeaux

mixture1 kg/100L 2 Air blast Oct-Nov

Mar-Aprcopperoxychloride

various 500 g/kg 400 g/100L 2 Air blast Oct-NovMar-Apr

copperhydroxide

Kocide 500 g/kg 200-300g/100L

2 Air blast Oct-NovMar-Apr

Pesticides used on stone fruit in 1994-95



time ofseason

Herbicidesnorflurazon Solicam 800 g/kg 2.5-5.0 kg/ha 1 Boom springoxyfluorfen Goal 240 g/L 3.0-4.0 L/ha 1 “ springoryzalin Surflan 500 g/L 4.5-6.8 L/ha 1 “ springterbacil**(peaches only)

Sinbar 800 g/kg 2.2-3.5 kg/ha 1 “ spring

Insecticidespirimicarb Pirimor 500 g/kg 50g/100 L 1-2 Air Blast Aug-Decazinphos-methyl

Gusathion 350 g/kg 75-100 g/100L 1-3 “ Sep-May

carbaryl various 800 g/kg 100 g/100L 1 “ Oct-Decchlorpyrifos Lorsban 500 g/L 2 L/ha 1 Air Blast or

bait“

endosulfan Endosulfan 350 g/L 190 ml/100 L 1 Air Blast Septdiazinon Gesapon 800 g/L 65 ml/100L 1 “ Jun-AugB. thuringiensis Dipel 1600 U 25 g/100 L 1-3 “ Sep-DecAcaracides (not used on apricots)clofentezine Apollo 500 g/L 30 ml/100L 1 Air Blast Nov-Jandicofol Kelthane 480 g/L 100 ml/100L 1 “ Sep-Octfenbutatinoxide

Torque 550 g/L 20-40 ml/100L 1-2 “ Nov-Jan

hexythiazox Calibre 100 g/L 25 ml/100L 1 “ Nov-Janpropargite Omite 300 g/kg 100-200 g/100L 1-2 “ Nov-JanFungicidesbenomyl Benlate 500 g/kg 50-60 g/100 L 1-4 Air Blast Aug-Marchlorothalonil Bravo 500 g/L 230 ml/100 L 1-4 “ Sep-Marcopperoxychloride

various 500 g/kg 400 g/100 L 1-2 “ Aug/Apr

copper sulphate Bluestone 250 g/kg 0.6-1.0 kg/100L 1-2 “ Aug/Aprcuprichydroxide

Kocide 500 g/kg 200 g/100 L 1-2 “ Aug/Apr

dithianon Delan 750 g/kg 100 g/100 L 1-4 “ Sep-Mariprodione Rovral 250 g/L 50 g/100 L 1-4 “ Sep-Marmancozeb Dithane 800 g/kg 150 g/100 L 1-4 “ Sep-Marprocymidone Sumisclex 500 g/kg 50 g/100 L 1-4 “ Sep-Marpropiconazole Tilt 250 g/L 10 ml/100 L 1-4 “ Sep-Marthiram various 800 g/kg 150 g/100 L 1-2 “ Dec-Jantriforine Saprol 190 g/L 100 ml/100L 1-4 “ Sep-Marvinclozolin Ronilan 500 g/L 50 g/100 L 1-4 “ Sep-Marzineb various 800 g/L 150 g/100 L 1-3 “ Sep-Febziram various 900 g/kg 200 g/100 L 1 “ Aug

Pesticides used on vegetables in 1994-95

Area of vegetables grown, 1992 (hectares)carrots/

parsnipsonions cucurbit

stomatoes potatoes total

Murrumbidgee Irrigation Area 1200 1150 2000 800 approx 500 5150Coleambally Irrigation Area 0 0 0 0 approx 500 0Murray Valley 15 200 0 approx 800 0 1015Total 1215 1350 2000 1600 1000 7165

Pesticides used on carrots and parsnips in 1994-95Chemical Trade name active

ingredientapplicationrate number method

time ofseason

Herbicideslinuron Afalon 500 g/kg 1.1-4.5 kg/ha 1 boom Aug-Mayfluazifop-p-butyl Fusilade 212 g/L 0.5-1.0 L/ha 1 boom,aerial Aug-Maytrifluralin Treflan 400 g/L 1.4-2.8 L/ha 1 boom Aug-MayInsecticideschlorpyrifos Lorsban 500 g/L 700 ml/ha 1-2 boom Aug-Maydimethoate Rogor 400 g/L 800 ml/ha 1-2 boom,aerial Aug-Mayendosulfan Endosulfan 350 g/L 190 ml/100L 1-2 boom,aerial Aug-MayFungicidesbenomyl Benlate 500 g/kg 2.0 kg/ha 1-2 boom,aerial Aug-Maymancozeb Dithane 200 g/kg 1.7-2.2 kg/ha 1-2 boom Aug-Mayvinclozolin Ronilan 500 g/L 0.75-1.0L/ 100L 1 boom Aug-Maycopper hydroxide Kocide 500 g/kg 2.2 kg/ha 1-2 boom all year

Pesticides used on onions in 1994-95Chemical Trade name active

ingredient

applicationrate number

method

time ofseason

Herbicideslinuron Afalon 500 g/kg 0.3-0.5 kg/ha 1-2 boom Apr-Octfluazifop-p-butyl Fusilade 212 g/L 0.5-1.5 L/ha 1-2 boom Apr-Octioxynil Totril 250 g/L 2.1-2.8 L/ha 1 boom May-Sepmethabenzthiazuron Tribunil 700 g/kg 1-3 L/Ha 1 boom Apr-May

Septmethazole Probe 800 g/kg 0.7-2.7 kg/ha 1-2 boom Apr-SepInsecticideschlorpyrifos Lorsban 500 g/L 700 ml/ha 1 boom Apr-Sepdimethoate Rogor 400 g/L 800 ml/ha 1-2 boom,aerial May-Octparathion Parathion 500 g/L 0.3 L/ha 1-2 boom,aerial May-OctFungicidesmancozeb Dithane 200 g/kg 1.7-3.5 kg/ha 1-3 boom,aerial May-Novmancozeb+metalaxyl

Ridomil 640 g/kg,40 g/kg

2.5 kg/ha 1-2 boom,aerial May-Nov

copper hydroxide Kocide 500 g/kg 2.2 kg/ha 1-2 boom,aerial May-Nov

Pesticides used on cucurbits in 1994-95Chemical Trade name active


time ofseason

Herbicidessethoxydim Sertin 186 g/L 1.0 L/ha 1 boom Oct-Decfluazifop-p-butyl Fusilade 212 g/L 0.5-1.5 L/ha 1-2 boom Oct-DecInsecticidesendosulfan Endosulfan 350 g/L 190 ml/100L 1-2 boom Oct-Febdimethoate Rogor 400 g/L 750 ml/ha 1-2 boom Oct-Febmalathion Maldison 500 g/L 0.2 L/100L 1-2 boom Oct-Febcarbaryl Carbaryl 500 g/L 2 L/ha 1-2 boom,aerial Oct-FebFungicidesmancozeb Dithane 200 g/kg 0.7-2.2 kg/ha 1-2 boom Nov-Febmancozeb+metalaxyl

Ridomil 640 g/kg,40 g/kg

2.5 kg/ha 1-2 boom,aerial Nov-Feb

wettable sulphur various 800 g/kg 200 g/100L 2-3 boom Nov-Febtriadimenol Bayfidan 250 g/L 400 ml/Ha 1-2 boom, aerial Nov-Febdimethirimol Milcurb 125 g/L 1-2 L/ha 1-2 boom,aerial Nov-Febbupirimate Nimrod 250 g/L 60 ml/100L 1-2 boom Nov-Febtriadimeton Bayleton 125 g/L 400 ml/Ha 1-2 boom, aerial Nov-Febpyrazophos Afugan 295 g/L 500 ml/ha 1-2 boom,aerial Nov-Febfenarimol Rubigan 120 g/L 0.2 L/ha 1-2 boom,aerial Nov-Febcopper hydroxide Kocide 500 g/L 200 g/100L 1-2 boom,aerial Nov-Feb

Pesticides used on tomatoes in 1994-95Chemical Trade name active


time ofseason

Herbicidesnapropamide Devrinol 500 g/kg 4.5-6.7 kg/ha 1 boom Oct-Dectrifluralin Treflan 400 g/L 1.4-2.8 L/ha 1 boom Oct-Decfluazifop-p-butyl Fusilade 212 g/L 0.5-1.0 L/ha 1 boom Nov-JanInsecticidesendosulfan Endosulfan 350 g/L 2.1 L/ha 1-3 boom Oct-Mardimethoate Rogor 400 g/L 0.75 L/ha 1-3 boom Oct-Mardeltamethrin Decis 25 g/L 0.5 L/ha 1-3 boom Oct-Marchlorpyrifos Lorsban 500 g/L 1.5-2.0 L/ha 1-3 boom Oct-MarFungicidesmancozeb Dithane 200 g/kg 2-3 kg/ha 1-3 boom Oct-Marcopper oxychloride various 500 g/kg 0.4 kg/100L 1-3 boom Oct-Marwettable sulphur various 800 g/kg 300 g/100L 1-3 boom Oct-Marcopper hydroxide Kocide 500 g/L 2.2 kg/ha 1-3 boom Oct-Mar

Pesticides used on potatoes in 1994-95Chemical Trade name active


time ofseason

Herbicideslinuron various 500 g/kg 2.2-4.5kg/ha 1 (minor use) Boom Aug & Febmetribuzin Sencor 700 g/kg 0.5-0.7kg/ha 1 (minor use) Boom “fluazifop-p-butyl Fusilade 212 g/L 0.5-1.0 L/ha 1 (minor use) Boom Sept-Oct

Mar-AprInsecticidesmonocrotophos Azodrin 400 g/L 1.0 L/ha 1-3 Boom Aug-Aprchlorpyrifos Lorsban 500 g/L 0.7 L/ha 1-3 “ Aug-Sept

Feb-Marendosulfan Endosulfan 350 g/L 2.1 L/ha 1-3 “ Aug-Aprdimethoate Rogor 400 g/L 0.8 L/ha 1-3 “ “Fungicidesmancozeb various 800 g/kg 1.7-2.2kg/ha 1-2 Boom/

AerialJan-May

Knockdown herbicides used in 1994-95

Chemical Trade name2 activeingredient

applicationrate number1 method

time ofseason

diquat Reglone 200 g/L 1.4-4.0 L/ha - boom all yearparaquat Gramoxone 200 g/L 1.5-2.0 L/ha - boom all yeardiquat/paraquat Sprayseed 75 g/L,

125 g/L1.4-4.0 L/ha 1 boom all year

glyphosate Roundup 360 g/L 2.0-9.0 L/ha - boom all yearglyphosate Roundup CT 450 g/L 1.2-2.4 L/ha 1 boom all yearNote 1: Number of applications quoted is only for seedbed preparation. Other uses for general weed control mayinvolve several applications over a season and no figures are quoted.Note 2: The trade names provided are examples only. There are several other brands and formulations available

Seed dressings

Practically all seeds sown commercially are treated with fungicide seed-dressing compounds tocontrol seed-borne diseases. The seed-dressing might also contain insecticides to control soilactive insects.

chemical trade name active ingredient product used cropfungicidesbenomyl Benlate 500 g/kg 200g/100 kg Vbenzothiazole Bawsan 320 g/L 75-100ml/100kg W,Bbitertanol Sibutol 100 g/kg 100g/100kg W,Bcarboxin Vitavax 750 g/L 70g/100kg W,B,Ofenaminosulf Lesan 50 g/kg 150g/100kg Wfenfuram Pano-ram 250 g/kg 150g/100kg W,B,Oflutriafol Armour 100 g/L 100ml/100kg W,B,Ometalaxyl Apron 350 g/kg 85-300g/100kg S,Vtebuconazole Raxil 25 g/kg 100g/100kg W,B,Othiram Thiram 800 g/kg 500g/100kg Vtriadimenol Baytan 150 g/L 100-150g/100kg W,B,OInsecticidescypermethrin - 4 g/L formulated in seed

dressingW,B,O

dimethoate Rogor 400 ml/L 330ml/100kg Cmalathion Maldison 1000 g/L 300ml/seedrate/ha RNote: crops, B=barley, W=wheat, O=oats, V=vegetables, R=rice, S=soybeans, C=canola

Adjuvants

All pesticide formulations contain adjuvants. These are necessary to enhance activity or toenable mixing of an otherwise insoluble active ingredient.

Adjuvants may include wetting agents, emulsifiers, dispersing agents, penetrants, anti-foamagents, inert carriers, buffering agents, stickers, petroleum solvents and other specialisedformulating products. The amount of these products in each formulation varies considerably, butcan comprise more than half of the final product applied to a crop. Commonly available wettingagents are listed below.

Chemical Trade Namenonyl phenol ethylene oxide condensate AGRAL 600

KENDRAL 600LE WETTX77

nonyl phenol ethylene oxide condensate+ dioctyl sodium sulphosuccinate

PLUS 50

nonyl phenol ethoxylatealcohol alkoxylate BS1000paraffin base petroleum oilpolyol fatty acid esterspolyethoxylated polyol fatty acid ester emulsifier

AGRIDEX

Linear (C9-C11)alcohol ethylene oxide condensate MONSOONmodified polydimethylsiloxane PULSEoctyl phenol ethoxylate WETTER TXdistillate fuel oilparaffinic mineral oils D.C. TRON

CALTEX LOVISCALTEX SUMMER SPRAYCALTEX WINTER SPRAYULVAPRON

References for pesticides used on irrigated crops

The NSW Department of Agriculture can provide up-to-date information on what pesticides arebeing used on irrigated crops. Otherwise, further information can be obtained from a variety ofreferences including the following:

• Sunflowers in Australia. Edited by Chris R. Warmington. Published by Pacific Seeds. 1981.• Farm Chemicals Handbook. 1991. Meister Publishing Company.• Orchard and Vineyard Plant Protection Guide for Inland N.S.W. Second edition 1992-93. NSW

Agriculture.• Peskem. 10th Edition August 1989, 13th Edition September 1993. Department of Plant Protection.

Queensland Agricultural College, Gatton Queensland.• Agricultural Product Guide. Products for Australian Agriculture from DOW Chemical Australia Limited.

3rd Edition August 1989.• AVPI. Agricultural and Veterinary Product Index. A complete chemical product guide 1993. MIMS

Australia.• Agricultural Chemicals. Book IV - Fungicides. 1991 Revision. W.T. Thompson. Thompson Publications.• Agricultural Chemicals. Book III - Miscellaneous Agricultural Chemicals. 1991-92 Revision. W.T.

Thompson. Thompson Publications.• Agricultural Chemicals. Book II - Herbicides. 1989-90 Revision. W.T. Thompson. Thompson

Publications.• A Manual of Australian Agriculture. Fourth Edition 1983. Edited by R.L. Reid. William Heinemann,

Melbourne.• The Pesticide Manual. A World Compendium. Eighth Edition 1987. Editor Charles R. Worthing. The

British Crop Protection Council.• The Australian Weed Control Handbook. Seventh Edition. J.T. Swarbrick 1984. Published by Plant Press.• Herbicide Handbook. Sixth Edition 1989. Published by Weed Science Society of America.• Vegetable Growing Handbook 1985. Murray & Riverina Region. Department of Agriculture NSW.

Published by Irrigation and Research Extension Committee, Griffith NSW.• Australian Vegetable Growing Handbook. June 1991. NSW Agriculture. Published by Irrigation Research

and Extension Committee Griffith NSW.• Recommendations for Weed Control in Temperate Australia. Volume 1, Volume 2, Part 1, Part 2. Robert

G. Richardson, Rosamond C.H. Shepherd. Published by Weed Science Society of Victoria Inc.• Rice Crop Protection Guide 1992; a supplement to “Rice growing in NSW”. Published by NSW Department

of Agriculture and Rice Research Committee.• Growing Cantaloupes Successfully. Gerard Kelly, John Salvestrin. Published by Irrigation Research and

Extension Committee, Griffith NSW.• INFOPEST; Chemicals for the Protection of Vegetable Crops. 1991, 2nd edition, Queensland Department of

Primary Industries, Information series QI91005.• INFOPEST; Chemicals for the Protection of Field Crops, Forage Crops and Pastures. 1991, 2nd edition,

Queensland Department of Primary Industries, Information series QI91006.

herbicides solubility(mg/L)

insecticides,fungicides

solubility(mg/L)

trifluralin 0.3 deltamethrin 0.1pendimethalin 0.3 cypermethrin 0.2fluazifop-p-butyl 2 endosulfan 0.32simazine 5 chlorpyrifos 1.1haloxyfop-methyl 9 dicofol 1.2thiobencarb 30 benomyl 4atrazine 32 azinphos-methyl 33diuron 37 carbaryl 120chlorsulfuron 100 malathion 145bensulfuron methyl 120 bromacil 815propanil 225 methidathion 220metsulfuron 270 methomyl 58,000metolachlor 530 trichlorfon 154,000MCPA 825 Bacillus thuringiensis not applicablemolinate 970dicamba 6,500glyphosate 10,000acrolein 210,000amitrole 280,000paraquat 620,000diquat 700,0002,4-D amine 800,000copper sulphate highly soluble

APPENDIX BSolubilities in water of the common pesticides

The following information was kindly provided by Graham Cook, Deputy Director, Division of AnalyticalLaboratories, NSW Department of Health, on 24th August 1995.

Testing of Rural Water Supplies

The Division of Analytical Laboratories routinely monitors the chemical and microbiological quality of drinkingwater from rural public water supplies.

Samples are provided by local councils and government authorities such as Public Works and the National Parks& Wildlife Service.

Samples are tested microbiologically for indicator organisms and chemically for a wide range of parameters andconstituents including agricultural chemical residues, with reference to the 1987 Guidelines for Drinking WaterQuality in Australia.

The Division’s Pesticide Residue Laboratory (PRL) prepares and distributes a water sampling program to eachPublic Health Unit indicating the frequency and sampling date for each rural water supply. The purpose of theprogram is to distribute the workload of the laboratory and to ensure that each water supply is sampled annually.It is the responsibility of the Public Health Unit to ensure that the sampling program is complied with. Theprogram doea not necessarily limit the number of samples of water a supply authority can submit and additionalsamples can be tested as required.

Where a potential public health issue arises related to water quality, the Division works closely with PublicHealth Units and the supply authority to identify and rectify the health issues.

The Murrumbidgee Irrigation Area is covered by the South Western Public Health Unit. This Unit currentlyencompasses 24 water supply authorities responsible for a total of 104 individual public water supplies. Detailsof the current water sampling program for Griffith, Leeton, Darlington Point and Deniliquin are tabled below.

Water Supply Council Sampling DateBeelbangera Griffith SeptemberHanwood Griffith SeptemberGriffith Griffith MarchYenda Griffith MarchWhitton Leeton DecemberMurrami Leeton DecemberLeeton Leeton JuneYanco Leeton JuneWamoon Leeton JuneDarlington Point Murrumbidgee MarchColeambally Murrumbidgee MarchDeniliquin Deniliquin April

Sampling dates and sample points may vary from year to year.

The chemical substances which the PRL now routinely tests for are listed below. The laboratory will test foradditional compounds subject to the availability of an appropriate test method and reference materials.

Pesticides and herbicides have not been detected in drinking water samples routinely tested by the PesticideResidues Laboratory.

APPENDIX C INFORMATION ON THE MONITORING OF DRINKINGWATER FOR PESTICIDE CONTAMINATION

Pesticide Residues Laboratory - Routinely Screened Pesticides (June 1995)

Organochlorine insecticidesHCB a-Chlordanea-BHC g-Chlordaneb-BHC p,p’-DDEg-BHC (Lindane) p,p’-DDDEndrin p,p’-DDTHeptachlor MethoxychlorHeptachlor epoxide a-EndosulfanAldrin b-EndosulfanDieldrin Endosulfan sulfateOxychlordaneDetection levels: 0.05 ug/L (water), 0.005 mg/kg (food) unless stated otherwise

Organophosphorus insecticidesM-Chlorpyrifos ProfenofosE-Chlorpyrifos EthoprofosM-Fenthion MethacrifosE-Fenthion CarbophenothionFenitrothion ChlorfenvinphosDiazinon TetrachlorvinphosM-Pirimiphos MethidathionE-Pirimiphos EthionM-Parathion Mevinphos*E-Parathion Dimethoate*Disulfoton Dichlorvos*Sulprofos MalathionSulfotepp ThiometonFenchlorphos PhorateM-Bromophos* = Routinely screened for only in food samples. Screened for in water upon request.Detection levels: 0 1 ug/L (water), 0.01 mg/kg (food) unless stated otherwise.

Acidic Herbicide2,4-D Bromoxynil2,4,5-T Triclopyr2,4-DB PentachlorophenolDicamba DichlorpropFenopropDetection levels: 0.5 ug/L (water) unless stated otherwise

Phenylurea & Triazine Herbicides*Atrazine DiuronSimazine LinuronPropazine FluometuronCyanazine MetrobromuronHaxezinone MethabenzthiazuronTerbuthylazine MetoxuronMetribuzin* Screened for in water upon request. Detection levels: 1.0 ug/L (water) unless stated otherwise

Synthetic Pyrethroids*Allethrin FenvalerateBioresmethrin CyhalothrinPermethrin DeltamethrinCypermethrin CyfluthrinFlumethrin* Screened for in water upon request. Detection levels: 0.5 ug/L (water) unless otherwise stated.

Routinely Screened Pesticides (June 1995) - continued

Non-Routine Pesticides and Organic Residues*Polyaromatic Hydrocarbons (PAHs) PropiconazolePolychlorinated Biphenyls (PCBs) GlyphosateDemeton ChlorfluazuronDemton-s-methyl CaptanOxydemeton-methyl M-AzinphosTrifluralin E-AzinphosBenfluralin d-BHCOmethoate CarbarylFenamiphos MCPACoumaphos E-BromophosDicofol PicloramChlorothalonil Chlordene*Screened in water upon request

Griff. 1

Site Description. M.I.A., Willbriggie. At guaged common drain of 15 rice/row crop farms.No supply dilution prior to guage.

Date: October/November 1991.Sampling: Daily,one litre amber glass bottle grab sample at guage.Tested for: Molinate (Mol), Atrazine (At), Malathion (Mal), Chlorpyrifos(Chp)Limit of Reporting: 0.05 µg/L for all. NOTE: Only positives (i.e. > LOR) reported.Analytical method: CSIRO Griffith LLE-GC/MS

NOTE: Load=24 h Discharge volume (Flow) * Average daily concentration ((Day1+day2)/2)

Load Load Load LoadFlow Mol Mol At At Mal Mal Chp Chp

Date ML/day µg/l g/day µg/l g/day µg/l g/day µg/l g/day

9/10 2.931 0.12 ---- ---- ---- 0.2 ---- ---- ----

10/10 6.349 0.09 0.7 ---- ---- ---- ---- ---- ----

11/10 5.256 0.05 0.4 ---- ---- ---- ---- ---- ----

12/10 2.650 0.09 0.2 ---- ---- 4 ---- ---- ----

13/10 5.512 ---- ND ---- ---- ---- ---- ---- ----

14/10 6.038 0.34 1.3 ---- ---- ---- ---- ---- ----

15/10 7.710 4.8 19.8 ---- ---- 5 ---- 0.16 ----

16/10 5.988 1.6 19.2 ---- ---- 0.18 ---- ---- ----

17/10 6.309 0.84 7.7 ---- ---- ---- ---- ---- ----

18/10 7.517 1.1 7.3 ---- ---- ---- ---- ---- ----

19/10 5.918 818 2423.7 ---- ---- ---- ---- 6.2 ----

20/10 4.626 7 1908.2 158 ---- ---- ---- ---- ----

21/10 4.664 11 42.0 112 1259 0.13 ---- ---- ----

22/10 3.769 3.3 26.9 101 803 ---- ---- ---- ----

23/10 4.328 1.5 10.4 53 667 ---- ---- ---- ----

24/10 5.730 4.3 16.6 16 395 ---- ---- ---- ----

25/10 6.759 7.5 39.9 40 379 ---- ---- ---- ----

26/10 4.700 4.5 28.2 18 273 ---- ---- ---- ----

27/10 4.402 6.6 24.4 13 136 ---- ---- ---- ----

28/10 6.493 3.6 33.1 84 630 0.33 ---- ---- ----

29/10 6.265 8.8 38.8 106 1190 0.24 1.79 ---- ----

30/10 5.627 11 55.7 98 1148 0.1 0.96 ---- ----

31/10 4.704 518 1244.2 133 1087 ---- ---- 0.32 ----

1/11 3.561 308 1470.7 94 808 0.11 0.20 0.43 1.34

2/11 3.650 340 1182.6 225 1164 0.07 0.33 0.29 1.31

3/11 4.028 195 1077.5 248 1905 ---- ---- 0.18 0.95

4/11 3.594 119 564.3 203 1621 ---- ---- 0.1 0.50

5/11 5.388 134 681.6 203 2188 ---- ---- 0.08 0.48

6/11 8.571 42 754.2 56 2220 ---- ---- 0.05 0.56

7/11 6.085 195 721.1 74 791 ---- ---- ---- ----

8/11 5.170 74 695.4 68 734 ---- ---- ---- ----

9/11 5.167 29 266.1 64 682 ---- ---- ---- ----

10/11 4.490 49 175.1 51 516 ---- ---- ---- ----

11/11 4.544 63 254.5 40 414 ---- ---- ---- ----

12/11 4.325 84 317.9 55 411 ---- ---- ---- ----

13/11 4.141 102 385.1 47 422 ---- ---- ---- ----

14/11 4.599 75 407.0 32 363 ---- ---- ---- ----

15/11 5.168 53 330.8 25 295 ---- ---- ---- ----

16/11 8.822 81 591.1 12 326 ---- ---- ---- ----

17/11 11.140 132 1186.4 11 256 ---- ---- ---- ----

18/11 5.371 149 754.6 11 118 ---- ---- ---- ----

19/11 3.549 106 452.5 10 75 ---- ---- ---- ----

20/11 2.991 86 287.1 8 54 ---- ---- ---- ----

21/11 6.480 6 298.1 3 71 ---- ---- ---- ----

22/11 7.346 18 88.2 12 110 ---- ---- ---- ----

23/11 4.862 15 80.2 9 102 ---- ---- 0.14 ----

24/11 4.095 15 61.4 7 66 ---- ---- ---- ----

25/11 4.177 6 43.9 3 42 ---- ---- ---- ----

26/11 2.446 9 18.3 4 17 ---- ---- ---- ----

27/11 2.752 10 26.1 4 22 ---- ---- ---- ----

28/11 4.067 13 46.8 9 53 ---- ---- ---- ----

29/11 4.799 17 72.0 8 82 ---- ---- ---- ----

---- = below limit of reporting (LOR); ND = not determined

APPENDIX D RAW DATA FROM CSIRO PESTICIDE MONITORINGPROGRAMS

Griff. 2

Site Description: M.I.A. , Willbriggie. At guaged common drain of 15 rice/row cropfarms.No supply dilution prior to guage.

Date: March/April 1992Sampling: Daily,one litre amber glass bottle grab sample at guage.Tested for: Molinate (Mol), Atrazine (At), Malathion (Mal), Chlorpyrifos(Chp),

Diuron* (Di), Bromacil (Bro)Limit of Reporting: 0.05 µg/L for all except bromacil 0.50 µg/L

NOTE: Only positives (i.e. > LOR) reportedMal, Chp, Bro not found.

Analytical method: CSIRO Griffith LLE-GC/MS

NOTE: Load = 24 h discharge volume (Flow)*average daily concentration ((day 1+day 2)/2). Load is calculated for two days where daily sample was missed.

Load Load Load

Flow Di Di Mol Mol At At

Date ML/day µg/L g/day µg/L g/day µg/L g/day

5.3.92 3.995 0.06 ND 0.13 ND 0.46 ND

6.3 5.829 ---- 0.17 0.12 0.73 0.72 3.44

7.3 4.596 ---- ND 0.12 0.55 0.59 3.01

8.3 3.972 ---- ND 0.11 0.46 0.74 2.64

9.3 5.796 ---- ND 0.14 0.72 0.51 3.62

10.3 6.795 ---- ND 0.11 0.85 0.47 3.33

11.3 5.888 ---- ND 0.12 0.68 0.42 2.62

12.3 6.119 ---- ND 0.13 0.76 0.54 2.94

13.3 5.604 ---- ND 0.09 0.62 0.4 2.63

14.3 5.397 No Sample

15.3 5.643 ---- ND 0.09 0.99 1.55 10.76

16.3 4.734 ---- ND 0.09 0.43 1.08 6.23

17.3 5.780 ---- ND 0.07 0.46 0.69 5.12

18.3 7.960 0.08 0.32 0.07 0.56 0.7 5.53

19.3 7.913 0.07 0.59 0.07 0.55 0.51 4.79

20.3 12.520 ---- 0.44 0.11 1.13 0.65 7.26


22.3 6.766 ---- ND 0.06 1.31 0.14 6.07

23.3 6.286 ---- ND ---- ND 0.15 0.91

24.3 9.051 ---- ND ---- ND 0.32 2.13

25.3 10.500 ---- ND ---- ND 0.2 2.73

26.3 10.670 ---- ND ---- ND 0.15 1.87

27.3 8.484 ---- ND ---- ND 0.12 1.15


29.3 5.877 ---- ND ---- ND 0.16 1.84

30.3 5.443 ---- ND ---- ND ---- 0.44

31.3 6.732 ---- ND 0.14 0.47 0.14 0.47

1.4.92 6.827 ---- ND 0.22 1.23 0.22 1.23

2.4 5.524 ---- ND ---- 0.61 0.14 0.99

3.4 4.080 ---- ND ---- ND 0.08 0.45

4.4 5.055 ---- ND ---- ND 0.17 0.63

5.4 2.300 ---- ND ---- ND ---- 0.20

6.4 1.233 ---- ND ---- ND ---- ND

7.4 0.877 ---- ND ---- ND ---- ND

8.4 0.514 ---- ND ---- ND ---- ND

9.4 0.777 ---- ND ---- ND ---- ND


Griff. 3

Site Description: M.I.A., Willbriggie. At guaged common drain of 15 rice/row cropfarms. No supply dilution prior to guage.

Date: October/November/December 1993Sampling: Daily, one litre amber glass bottle grab sample at guage.Tested for: Molinate (Mol), Atrazine (At), Malathion (Mal), Chlorpyrifos

(Chp), Metolachlor (Met), Thiobencarb (Thi), Bensulfuron (Ben),Endosulfan (End), Diuron (Di), Bromacil (Bro), Cypermethrin (Cyp)

Limit of Reporting: 0.05 µg/L for all but Bro (0.5 µg/L), Ben (0.25ug/L).Analytical method: CSIRO Griffith LLE-GC/MS

Note: Leakage at guage station made discharge figures unreliable.

Date Mal Chp Mol At Met BenSampled µg/L µg/L µg/L µg/L µg/L µg/L16/10 ND ND ND ND ND ND17/10 ---- 0.6 51 4.2 ND ND18/10 0.3 0.18 17 2.7 ND ND19/10 0.1 0.15 18.5 2.5 ND ND20/10 ---- 0.1 64 23 ND ND21/10 ---- 0.17 8.1 78 ND ND22/10 0.25 0.15 35 10 ND ND23/10 0.1 0.08 21 6.2 ND ND24/10 ---- 0.15 92 3.8 ND ND25/10 0.08 ---- 61 2.4 ND ND26/10 ---- 0.05 28 1 ND ND27/10 ---- 0.06 235 1.1 ND ND28/10 ---- 0.06 133 1.4 ND ND29/10 ---- ---- 110 2.4 ND ND30/10 ---- ---- 73 2.8 ND ND31/10 ---- ---- 58 2.7 ND ND1/11 ---- ---- 61 2.6 ND ND2/11 ---- ---- 31 1.06 ND ND3/11 ---- ---- 28 0.68 ND ND4/11 ---- ---- 36 0.56 ND ND5/11 ---- ---- 9.3 0.35 ND ND6/11 ---- ---- 13 0.3 ND ND7/11 ---- ---- 15 0.4 ND ND8/11 ---- ---- 16 0.5 ---- 0.39/11 ---- ---- 15 0.5 ---- 0.210/11 ---- ---- 8.5 3.2 0.8 0.111/11 ---- ---- 13.5 56 64 ----12/11 ---- 0.28 12 49 47 ----13/11 ---- ---- 16.5 43 61 1.114/11 ---- ---- 15 30 37 0.9515/11 ---- ---- 10.5 11.5 8.5 0.416/11 ---- ---- 21 16.5 15 0.2517/11 ---- ---- 21 14.5 11 0.2518/11 ---- ---- 20 13 8.6 0.2519/11 ---- ---- 17 13.6 8 0.2520/11 ---- ---- 23 13 7.1 0.4521/11 ---- ---- 11 9 8.7 1.822/11 ---- ---- 29 26 66 1.123/11 ---- ---- 21 39 78 0.5624/11 ---- ---- 20 27 58 0.5625/11 ---- ---- 18.5 19 42 0.5626/11 ---- ---- 20 13 30 0.927/11 ---- ---- 16.5 11 21.8 0.828/11 ---- ---- 12 11 20 0.729/11 ---- ---- 7.9 11.5 19.5 0.730/11 ---- ---- 5.9 8.7 14 1.11/12 ---- ---- 6.2 4.1 7.8 22/12 ---- ---- 32 3.4 5.4 3.13/12 ---- ---- 36 2.7 3.7 2.14/12 ---- ---- 41 5.3 6.7 1.75/12 ---- ---- 27 6.4 11 1.26/12 ---- ---- 47 4.7 8.5 37/12 ---- ---- 46 5.4 12 2.88/12 ---- ---- 15 7.6 19 19/12 ---- ---- 12.5 6.6 76 1


Griff. 4

Site Description: M.I.A., Willbriggie. At common drain of 5 farm upper catchment.Rice/row crops. Nearest farm drain above sampling point is 1.2 km

Date: October/November/December 1993Sampling: 24 h composite samples in cooled glass container.Tested for: Molinate (Mol), Atrazine (At), Malathion (Mal), Chlorpyrifos (Chp),

Metolachlor (Met), Thiobencarb (Thi), Bensulfuron (Ben), Endosulfan(End), Diuron (Di), Bromacil (Bro), Cypermethrin (Cyp)

Limit of Reporting: 0.05 µg/L for all but Bro (0.5 µg/L), Ben (0.25 µg/L).Analytical method: CSIRO Griffith LLE-GC/MS

Note: Load (g/day) = composite sample µg/L * discharge volume (day1+day2)/2) ---- = below limit of reporting (LOR); ND = not determined

Load Load Load Load Load Load Load

Date Flow Mal Mal Chp Chp Mol Mol At At Met Met Ben Ben Thi Thi

Sampled ML/day µg/L g/day µg/L g/day µg/L g/day µg/L g/day µg/L g/day µg/L g/day µg/L g/day

16/10 ND ---- ND ---- ND 5.5 ND 6 ND ND ND ND ND ND ND

17/10 ND ---- ND ---- ND 78 ND 57 ND ND ND ND ND ND ND

18/10 1.67 ---- ND ---- ND 40 ND 27 ND ND ND ND ND ND ND

19/10 1.06 ---- ND 0.05 0.07 79 107.84 20 27.30 ND ND ND ND ND ND

20/10 0.33 0.2 0.14 ---- ND 88 61.27 4.5 3.13 ND ND ND ND ND ND

21/10 0.34 ND ND ND ND ND ND ND ND ND ND ND ND ND ND

22/10 0.36 5.5 1.91 ---- ND 120 41.76 3 1.04 ND ND ND ND ND ND

23/10 0.65 1.3 0.66 ---- ND 101 51.05 2.1 1.06 ND ND ND ND ND ND

24/10 0.64 0.57 0.37 ---- ND 112 72.54 1.1 0.71 ND ND ND ND ND ND

25/10 0.63 0.2 0.13 ---- ND 93 59.09 0.85 0.54 ---- ND ---- ND ---- ND

26/10 0.58 0.09 0.05 ---- ND 75 45.41 2.5 1.51 ND ND ND ND ND ND

27/10 0.30 ---- ND ---- ND 82 36.25 3.2 1.41 ND ND ND ND ND ND



30/10 0.06 ---- ND ---- ND 21 2.08 11 1.09 ---- ND ---- ND ---- ND




3/11 0.10 ---- ND ---- ND 27 2.11 1 0.08 ND ND ND ND ND ND




7/11 0.13 ---- ND ---- ND 5.1 0.74 7.5 1.09 ND ND ND ND ND ND

8/11 0.08 ---- ND ---- ND 4.7 0.47 8.7 0.88 ---- ND 0.15 0.02 ---- ND

9/11 0.18 ---- ND ---- ND 2.6 0.33 88 11.28 140 17.94 ---- ND ---- ND

10/11 3.19 ---- ND ---- ND 2.2 3.71 63 106.19 120 202.26 0.1 0.17 ---- ND

11/11 0.63 ---- ND ---- ND 1.5 2.87 43 82.23 70 133.86 0.1 0.19 ---- ND

12/11 0.28 ---- ND ---- ND 1.9 0.87 30 13.67 44 20.05 ---- ND ---- ND

13/11 0.15 ---- ND ---- ND 1 0.21 16 3.40 42 8.92 0.1 0.02 ---- ND

14/11 0.16 ---- ND ---- ND 0.8 0.12 12 1.83 32 4.88 0.15 0.02 ---- ND

15/11 0.16 ---- ND ---- ND 0.69 0.11 14 2.22 27 4.28 0.1 0.02 ---- ND

16/11 0.19 ---- ND ---- ND 0.7 0.12 14.5 2.51 24 4.15 ---- ND ---- ND

17/11 0.16 ---- ND ---- ND 0.7 0.12 11.5 1.99 16 2.76 ---- ND ---- ND

18/11 0.31 ---- ND ---- ND 45 10.50 11 2.57 8.8 2.05 0.1 0.02 ---- ND

19/11 1.00 0.05 0.03 ---- ND 185 121.08 13.5 8.84 21 13.74 2.3 1.51 0.06 0.04

20/11 0.89 0.06 0.06 ---- ND 46 43.52 38 35.95 102 96.50 1.1 1.04 0.1 0.09

21/11 1.38 ---- ND ---- ND 34 38.57 41 46.51 110 124.78 1.1 1.25 0.07 0.08

22/11 1.86 ---- ND 0.06 0.10 19.5 31.60 30.6 49.58 54 87.50 0.7 1.13 ---- 0.00

23/11 0.60 ---- ND 0.07 0.09 28 34.47 15 18.47 42 51.71 1 1.23 0.08 0.10

24/11 0.82 ---- ND ---- 0.00 20 14.23 13.5 9.60 42 29.88 1.1 0.78 1.9 1.35

25/11 0.79 ---- ND 0.05 0.04 25 20.17 6.6 5.32 25 20.17 2.1 1.69 3.1 2.50

26/11 0.76 ---- ND ---- ND 24 18.55 3.8 2.94 12 9.28 2.5 1.93 2 1.55

27/11 0.49 ---- ND ---- ND 23 14.32 2.6 1.62 7.5 4.67 3 1.87 1.7 1.06

28/11 0.62 ---- ND ---- ND 110 61.30 2.6 1.45 5.6 3.12 4.3 2.40 1.2 0.67

29/11 1.22 ---- ND ---- ND 269 248.69 4.2 3.88 12 11.09 5.7 5.27 0.8 0.74

30/11 0.78 ---- ND ---- ND 90 90.33 9.4 9.43 24 24.09 2 2.01 0.18 0.18

1/12 0.80 ---- ND ---- ND 60 47.52 5.3 4.20 14.5 11.48 1.4 1.11 ---- ND

2/12 0.42 ---- ND ---- ND 60 36.55 3.9 2.38 8.3 5.06 1.9 1.16 ---- ND

3/12 0.69 ---- ND 0.03 0.02 73 40.26 5.4 2.98 9 4.96 0.6 0.33 ---- ND

4/12 0.77 ---- ND 0.05 0.04 86 62.48 5.6 4.07 12 8.72 5 3.63 ---- ND

5/12 0.95 ---- ND 0.05 0.04 31 26.56 9.9 8.48 25 21.42 1.8 1.54 ---- ND

6/12 0.71 ---- ND 0.05 0.04 25 20.68 7.8 6.45 21 17.37 1.2 0.99 ---- ND

7/12 0.82 ---- ND 0.053 0.04 18 13.71 8 6.09 21 16.00 0.7 0.53 ---- ND

8/12 0.52 ---- ND 0.045 0.03 16 10.70 5.5 3.68 13.5 9.03 0.7 0.47 ---- ND

9/12 0.56 ---- ND 0.035 0.02 17 9.23 3.7 2.01 10.7 5.81 1 0.54 ---- ND

Griff. 5

Site Description. M.I.A., Willbriggie. At common drain of 5 farm upper catchment.Rice/row crops. Nearest farm drain above sampling point is 3.1km

Date: October/November/December 1993Sampling: 24 h composite samples in cooled glass container.Tested for: Molinate (Mol), Atrazine (At), Malathion (Mal), Chlorpyrifos (Chp),

Metolachlor (Met), Thiobencarb (Thi), Bensulfuron (Ben), Endosulfan(End), Diuron (Di), Bromacil (Bro), Cypermethrin (Cyp)

Limit of Reporting: 0.05 µg/L for all but Bro (0.5 µg/L), Ben (0.25 µg/L).Analytical method: CSIRO Griffith LLE-GC/MSLoad (g/day) = composite sample µg/L * discharge volume (day1+day2)/2) ---- = below limit of reporting (LOR); ND = not determined

Load Load Load Load Load Load Load

Date Flow Mal Mal Chp Chp Mol Mol At At Met Met Ben Ben Thi Thi

Sampled ML/day µg/L g/day µg/L g/day µg/L g/day µg/L g/day µg/L g/day µg/L g/day µg/L g/day

16/10 ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND

17/10 ND ND ND ND ND ND ND ND ND ND ND ND ND ND ND

18/10 1.67 ---- ND ---- ND 38 ND 45 ND ND ND ND ND ND ND




22/10 0.36 0.15 0.05 ---- ND 64 22.27 4 1.39 ND ND ND ND ND ND













4/11 0.12 ---- ND ---- ND 3.6 0.39 5 0.55 ND ND ND ND ND ND




8/11 0.08 ---- ND ---- ND 4.5 0.45 2 0.20 ---- ND ---- ND ---- ND

9/11 0.18 ---- ND ---- ND 2.3 0.29 53 6.79 67 8.59 ---- ND ---- ND

10/11 3.19 ---- ND ---- ND 1 1.69 65 109.56 110 185.41 ---- ND ---- ND

11/11 0.63 ---- ND ---- ND 0.9 1.72 58 110.91 85 162.55 0.2 0.38 ---- ND

12/11 0.28 ---- ND ---- ND 0.7 0.32 39 17.77 82 37.37 0.2 0.09 ---- ND

13/11 0.15 ---- ND ---- ND 0.64 0.14 31 6.58 60 12.74 0.15 0.03 ---- ND

14/11 0.16 ---- ND ---- ND 0.7 0.11 24 3.66 43 6.56 0.15 0.02 ---- ND

15/11 0.16 ---- ND ---- ND 0.52 0.08 14 2.22 23 3.64 0.1 0.02 ---- ND

16/11 0.19 ---- ND ---- ND 0.5 0.09 10.7 1.85 23 3.97 ---- ND ---- ND

17/11 0.16 ---- ND ---- ND 0.5 0.09 10 1.73 19 3.28 ---- ND ---- ND

18/11 0.31 ---- ND ---- ND 0.6 0.14 10.5 2.45 16.5 3.85 ---- ND ---- ND

19/11 1.00 ---- ND ---- ND 7.9 5.17 9.5 6.22 11.5 7.53 ---- ND ---- ND

20/11 0.89 ---- ND ---- ND 90 85.15 31 29.33 70 66.23 1.5 1.42 ---- ND

21/11 1.38 ---- ND ---- ND 35 39.70 34 38.57 89 100.96 1 1.13 ---- ND

22/11 1.86 ---- ND ---- ND 18.5 29.98 40.5 65.62 65 105.32 0.7 1.13 ---- ND

23/11 0.60 ---- ND ---- ND 15 18.47 25 30.78 58 71.41 0.56 0.69 ---- ND

24/11 0.82 ---- ND ---- ND 20 14.23 15 10.67 42 29.88 1.2 0.85 ---- ND

25/11 0.79 ---- ND ---- ND 13 10.49 16 12.91 52 41.95 1.1 0.89 ---- ND

26/11 0.76 ---- ND ---- ND 12 9.28 11 8.50 36 27.83 1.7 1.31 ---- ND

27/11 0.49 ---- ND ---- ND 12.5 7.79 5.9 3.67 22 13.70 2.1 1.31 ---- ND

28/11 0.62 ---- ND ---- ND 10 5.57 4 2.23 13 7.24 2.4 1.34 ---- ND

29/11 1.22 0.05 0.05 ---- ND 13 12.02 3.2 2.96 8.1 7.49 2.8 2.59 ---- ND

30/11 0.78 ---- ND ---- ND 172 172.63 6.3 6.32 13.8 13.85 5 5.02 ---- ND

1/12 0.80 ---- ND 0.015 0.01 66 52.27 9 7.13 20 15.84 1.7 1.35 ---- ND

2/12 0.42 ---- ND ---- ND 42 25.58 6.6 4.02 17.5 10.66 1.5 0.91 ---- ND

3/12 0.69 ---- ND ---- ND 30 16.55 4.9 2.70 11.2 6.18 1.5 0.83 ---- ND

4/12 0.77 ---- ND 0.01 0.01 59 42.86 5.4 3.92 9.6 6.97 3 2.18 ---- ND

5/12 0.95 ---- ND 0.05 0.04 60 51.41 5.3 4.54 15 12.85 4.4 3.77 ---- ND

6/12 0.71 ---- ND 0.02 0.02 23 19.03 9.2 7.61 25 20.68 1.6 1.32 ---- ND

7/12 0.82 ---- ND 0.017 0.01 20 15.24 7.5 5.71 18 13.71 1 0.76 ---- ND

8/12 0.52 ---- ND 0.013 0.01 14 9.36 8 5.35 19 12.71 0.65 0.43 ---- ND

9/12 0.56 ---- ND ---- ND 9.2 4.99 5.7 3.09 14.5 7.87 0.8 0.43 ---- ND

Griff. 6

Site Description. M.I.A., Willbriggie. At Sturt Canal Supply. Branch off Adams Road.

Date: October/November/December 1993Sampling: Daily Grab sample in 1 Litre amber glass BottleTested for: Molinate (Mol), Atrazine (At), Malathion (Mal), Chlorpyrifos (Chp), Metolachlor

(Met), Thiobencarb (Thi), Bensulfuron (Ben), Endosulfan (End), Diuron (Di),Bromacil (Bro), Cypermethrin (Cyp)



Date Malath Chlorp Mol AtrazSampled ug/L ug/L ug/L ug/L

19/10 ---- ---- 0.1 ----20/10 ---- ---- 0.45 ----21/10 ---- ---- 0.32 ----22/10 ---- ---- 0.3 0.3523/10 ---- ---- 0.26 ----24/10 ---- ---- 0.08 ----25/10 ---- ---- 0.11 ----26/10 ---- ---- 0.35 ----27/10 0.06 0.05 0.65 ----28/10 ---- ---- 0.2 ----29/10 ---- ---- 0.55 ----30/10 ---- ---- 0.17 ----31/10 ---- ---- 0.24 ----1/11 ---- ---- 0.15 ----2/11 ---- ---- 0.45 ----3/11 ---- ---- 3.1 ----4/11 ---- ---- 1.8 ----5/11 ---- ---- 3.3 ----6/11 ---- ---- 3.4 ----7/11 ---- ---- 1.6 ----8/11 ---- ---- 0.2 ----9/11 ---- ---- 0.1 ----

10/11 ---- ---- 0.15 ----11/11 ---- ---- 0.07 ----12/11 ---- ---- 0.09 ----13/11 ---- ---- 0.1 ----14/11 ---- ---- 0.08 ----15/11 ---- ---- 0.1 ----16/11 ---- ---- 0.05 ----17/11 ---- ---- 0.3 ----18/11 ---- ---- 0.1 ----19/11 ---- ---- 0.05 ----20/11 ---- ---- 0.12 ----21/11 ---- ---- 0.17 ----22/11 ---- ---- ---- ----23/11 ---- ---- 0.07 0.0724/11 ---- ---- 1.1 ----25/11 ---- ---- 3.6 ----26/11 ---- ---- 2.2 0.0527/11 ---- ---- 2 0.0628/11 ---- ---- 0.6 ----29/11 ---- ---- ---- ----30/11 ---- ---- 0.05 0.111/12 ---- ---- ---- 0.072/12 ---- ---- ---- ----3/12 ---- ---- ---- ----4/12 ---- ---- 0.07 0.065/12 ---- ---- ---- 0.16/12 ---- ---- ---- ----7/12 ---- ---- 0.04 0.078/12 ---- ---- 0.08 ----9/12 ---- ---- 0.04 ----

Griff. 7

Site Description: M.I.A., Willbriggie. From individual rice farm drainages.Date: October/November/December, 1992 and one in April, 1992.Sampling: Daily grab sample in 1 litre amber glass bottle. Sample at farm drain exit (=D).

Discharge measured for some (dye).Second sample from nearest rice bay to drain (=B).

Tested for: Molinate (Mol), Atrazine (At), Malathion (Mal), Chlorpyrifos (Chp), Thiobencarb(Thi), Diuron (Di), Bromacil (Bro).


Note: (W) and (E) refer to West and East rice paddies with a common drain.Load (mg/minute) = Discharge (L/min) * concentration (ug/L)/1000 ---- = below limit of reporting (LOR); ND = not determined

Load Load Load LoadSample Farm Sample Flow Mol Mol At At Mal Mal Chp Chp

Date L/min ug/L mg/min ug/L mg/min ug/L mg/min ug/L mg/min1.4.92 M 80A ---- 0.45 ---- ----

19.10.92 EA 1B 0.23 ---- 5 ----1D ND ---- ND ---- ND 0.6 ND ---- ND

23.10.92 EA 2B 1840 ---- 5.5 382D ND 900 ND ---- ND 15 ND 6.5 ND

26.10.92 EA 3B 1310 ---- 0.32 4.23D ND 460 ND ---- ND 0.54 ND 0.35 ND

28.10.92 B 4B 1800 ---- 59 6.94D ND 1480 ND ---- ND 5.5 ND 7.1 ND

5.11.92 M 6B 28 ---- ---- ----6D 5914 34 201.1 ---- ND 0.07 0.41 0.15 0.89

5.11.92 B 7B 330 ---- 0.9 0.257D 153 220 33.7 ---- ND 0.07 0.01 ---- ND

5.11.92 A 8B 225 ---- ---- 0.98D 106 80 8.5 ---- ND 0.12 0.01 0.1 0.01

5.11.92 SD 9B(W) 830 ---- 0.62 ----9B(E) 190 ---- 56 ----

9D 282 680 191.8 ---- ND 7.5 2.12 ---- ND5.11.92 M 10B 380 ---- 125 ----

10D 1014 45 45.6 ---- ND 8.5 8.62 ---- ND17.11.92 AN 11B 365 ---- ---- 0.93

11D 298 260 77.5 ---- ND ---- ND 0.45 ND17.11.92 B 12B 165 ---- ---- ----

12D 84.6 150 12.7 ---- ND ---- ND ---- ND17.11.92 EA 13B 28 ---- ---- 0.2

13D 42.4 68 2.9 ---- ND ---- ND ---- ND17.11.92 SD 14B(W) 275 0.07 0.17 ----

14B(E) 54 ---- 0.14 ----14D 126 160 20.2 ---- ND ---- ND ---- ND

17.11.92 M 15B 410 0.1 1.44 0.5115D 646 285 184.1 0.9 0.58 0.35 0.23 0.2 0.13

27.11.92 B(W) 17B 70 ---- ---- ----17D 246 63 15.5 ---- ND ---- ND ---- ND

27.11.92 B(E) 18B 35 ---- ---- ----18D 118 58 6.8 ---- ND ---- ND ---- ND

27.11.92 EA(E) 19B 7.5 ---- ---- ----19D 57.2 25 1.4 ---- ND ---- ND ---- ND

27.11.92 M 20B 81 0.05 ---- ----20D 282 76 21.4 0.25 0.07 ---- ND ---- ND

11.12.92 M 21D 91.5 43 3.9 ---- ---- ----11.12.92 B(W) 22B 6.7 ---- ---- ----

22D 68.7 14 1.0 ---- ND ---- ND ---- ND11.12.92 B(E) 23B 7.7 ---- ---- ----

23D 255 10.7 2.7 ---- ND ---- ND ---- ND11.12.92 SD 24B(W) 25 ---- ---- ----

24B(E) 14.5 ---- ---- ----24D(W) 191 11 2.1 ---- ND ---- ND ---- ND24D(E) 312 4.8 1.5 ---- ---- ----

11.12.92 OC 25B 5.9 ---- ---- ----25D 4146 5.7 23.6 ---- ND ---- ND ---- ND

Griff. 8

Site Description: MIA, Hanwood. Sampling in rice bays to determine pesticide dissipationrates. Two farms monitored (059 and 060).Date: October/November 1991.Sampling: Daily, one litre amber glass bottles at (1) bay nearest supply (A) and (2) bay

nearest drain (B)Tested for: Molinate (Mol), Malathion (Mal), Chlorpyrifos (Chp)Limit of Reporting: 0.05 µg/L for allAnalytical method: CSIRO Griffith LLE-GC/MS

Farm 59Date Molinate (µg/L) Malathion (µg/L) Chlorpyrifos (µg/L)

A B A B A B18/10 70 40 36.00 34.00 1.70 0.6719/10 28 29 13.00 28.00 0.39 0.4120/10 438 3696 6.00 1.00 0.80 4.7021/10 157 3300 0.28 22.00 0.59 2.3022/10 182 1015 0.40 11.00 0.33 2.0023/10 182 883 0.43 5.50 0.25 1.3024/10 82 1370 0.20 4.30 0.23 1.4025/10 9 1067 0.06 2.00 0.07 0.9026/10 10 891 0.08 1.10 0.06 0.4727/10 15 1195 ---- 0.68 ---- 0.2528/10 15 774 0.06 0.40 0.06 0.2429/10 13 476 0.05 0.09 0.05 0.1530/10 10 720 0.08 0.27 ---- 0.1731/10 6 440 ---- 0.10 ---- ----1/11 6 ND ---- ND ---- ND2/11 8 388 ---- ---- ---- ----3/11 6 83 ---- ---- ---- ----4/11 5 217 ---- ---- ---- ----5/11 4 190 ---- ---- ---- ----

Farm 60Date Molinate (µg/L) Malathion (µg/L) Chlorpyrifos (µg/L)

A B A B A B15/10 671 794 0.68 5.50 ---- ----16/10 226 400 0.58 3.10 2.00 1.0017/10 175 343 1.60 2.90 1.20 0.6018/10 88 263 0.44 1.40 0.50 0.3019/10 113 341 0.34 1.30 0.41 0.2620/10 74 270 0.25 0.80 0.32 0.2221/10 31 182 0.09 0.40 0.08 0.1722/10 23 230 0.14 0.32 0.09 0.1023/10 21 186 0.09 0.20 0.05 0.1324/10 16 150 0.12 0.17 0.05 0.0825/10 35 80 0.05 0.05 0.08 0.0826/10 15 115 ---- ---- ---- ----27/10 11 75 ---- ---- ---- ----28/10 555 150 3.80 3.60 69.00 0.4929/10 101 110 1.50 0.82 3.70 0.6830/10 76 73 0.24 0.10 2.00 0.6231/10 58 68 ---- ---- 0.73 0.361/11 12 683 ---- 0.54 ---- 0.202/11 13 443 ---- 0.28 ---- 0.203/11 11 322 ---- 0.22 0.05 0.154/11 11 57 ---- ---- 0.11 0.075/11 10 34 ---- ---- 0.13 0.066/11 13 26 ---- ---- 0.08 0.087/11 25 20 ---- ---- ---- ----8/11 13 24 ---- ---- ---- ----


Griff. 9

Site Description. M.I.A., Willbriggie. At individual farm drains of 5 farms with commoncatchment drain. Drain A. = drain from first farm ~ 1.9 km upstream of sampler.

Date: October/November/December 1993Sampling: One litre, amber glass bottle grab sample daily when drain is flowing. No sample

when there was no drainage.Tested for: Molinate (Mol), Atrazine (At), Malathion (Mal), Chlorpyrifos (Chp), Metolachlor



Date Farm Concentration (µg/L)

Sampled Drain A Mal Chp Mol At Met Ben Thi

16/10 1 ---- 1.2 60 26 ---- ---- ----

17/10 2 ---- 2.4 235 27 ---- ---- ----

19/10 3 ---- 2.3 227 30 ---- ---- ----

20/10 4 14 4.1 505 35 ---- ---- ----

21/10 5 0.3 3.6 676 36 ---- ---- ----

22/10 6 0.1 3.1 620 36 ---- ---- ----

23/10 7 0.06 2.6 625 43 ---- ---- ----

24/10 8 0.08 3.3 400 34 ---- ---- ----

25/10 9 0.1 2.5 63 30 ---- ---- ----

26/10 10 ---- 1.7 55 37 ---- ---- ----

27/10 11 ---- 1.6 440 28 ---- ---- ----

28/10 12 0.21 1.1 380 26 ---- ---- ----

29/10 13 ---- 0.95 107 24 ---- ---- ----

30/10 14 ---- 0.95 45 18.5 ---- ---- ----

31/10 15 ---- 0.8 21 14.7 ---- ---- ----

1/11 16 ---- 0.67 14.5 15 ---- ---- ----

3/11 17 ---- 0.7 14.5 21.5 ---- ---- ----

4/11 18 0.06 0.68 25 11 ---- ---- ----

5/11 19 ---- 0.63 13 6.1 ---- ---- ----

6/11 20 ---- 0.6 9.5 5.5 ---- ---- ----

7/11 21 ---- 0.45 11 8 ---- ---- ----

8/11 22 ---- 0.1 1.2 79 120 ---- ----

9/11 23 ---- 0.09 1.3 6.1 110 ---- ----

10/11 24 ---- 0.08 0.6 20 35 ---- ----

11/11 25 ---- 0.2 3.7 27 26 0.15 ----

12/11 26 ---- 0.28 6.5 53 44 ---- ----

13/11 27 ---- 0.18 5.5 24 24 0.1 ----

14/11 28 ---- 0.18 4.9 19 13 ---- ----

15/11 29 30.5 0.16 3.6 17.5 8 ---- ----

16/11 30 0.85 3 700 12 3 1.6 3

17/11 31 0.64 1 355 8.6 2.4 4.5 1.2

18/11 32 0.17 0.7 190 6.5 1.9 3.3 0.7

19/11 33 ---- 0.13 30 44 130 0.68 0.13

20/11 34 ---- 0.31 29 56 120 0.8 0.1

21/11 35 ---- 0.06 17 38 115 0.55 0.06

22/11 36 ---- 0.1 32 33 100 1.2 0.08

23/11 37 ---- 0.16 81 8.8 17 4 0.09

24/11 38 ---- 0.23 76 4.8 5.5 4.1 0.09

25/11 39 ---- 0.18 64 4.2 4.3 4.5 0.08

26/11 40 ---- 1.85 68 3.7 2.3 4.9 0.08

27/11 41 ---- 2.6 605 3.1 1.6 6.3 ----

28/11 42 ---- 0.86 361 8.1 14.5 5.6 0.1

29/11 43 ---- 0.18 52 5.6 18 0.8 ----

30/11 44 ---- 0.38 88 3.7 14 1.6 ----

1/12 45 ---- 0.24 180 3.6 1.3 3.8 ----

2/12 46 ---- 0.16 108 5 3.5 3.4 ----

3/12 47 ---- 0.15 89 9.4 3.6 4 ----

4/12 48 ---- 0.07 20 15 48 0.7 ----

5/12 49 ---- 0.06 30 8 20 0.6 ----

6/12 50 ---- 0.04 12.5 6 22 0.3 ----

7/12 51 ---- 0.06 28 3.2 9 0.6 ----

8/12 52 ---- 0.08 77 2.8 4.5 2.6 ----

9/12 53 ---- 0.05 51 1.6 2 2.3 ----


Griff. 10

Site Description: M.I.A., Willbriggie. At individual farm drains of 5 farms with commoncatchment drain. Second Farm Drain B; Third Drain D; Fourth Drain E.

Date: October/November/December 1993Sampling: One Litre, amber glass bottle grab sample daily when drain was flowing.Tested for: Molinate (Mol), Atrazine (At), Malathion (Mal), Chlorpyrifos (Chp), Metolachlor


Limit of Reporting: 0.05 µg/L for all but Bro (0.5 µg/L), Ben (0.25 µg/L). NOTE: Onlypositives (i.e. > Limit Of Reporting) reported.


Farm B Date Concentration(µg/L)

Farm C Date Concentration(µg/L)

Sampled Mal Chp Mol At Sampled Mol At

17/10 ---- 0.05 235 0.05 19/10 0.18 ----

19/10 ---- ---- 135 ---- 20/10 0.18 ----

20/10 21 0.11 214 ---- 21/10 0.17 ----

21/10 20 0.07 200 ---- 25/10 0.26 ----

22/10 4.8 0.08 165 ---- 3/11 31 1.8

23/10 3.6 0.08 159 ----

24/10 1.1 0.05 136 ----

25/10 1 0.06 141 ----

26/10 0.35 ---- 120 ----

27/10 0.25 ---- 93 ----

28/10 ---- ---- 75 ----

Farm D Date Concentration(µg/L)

Sampled Malath Chlorp Mol

20/10 ---- ---- 0.21

21/10 ---- ---- 0.21

22/10 0.55 ---- 0.16

23/10 0.09 ---- 0.27

24/10 0.13 ---- 9

25/10 0.08 ---- 8.8

26/10 ---- ---- 7.3

27/10 ---- 0.1 6.3

28/10 0.22 0.09 13

29/10 20 0.18 470

30/10 8 0.26 302

31/10 4.8 0.27 193

Farm E Date Concentration(µg/L)

Sampled Mal Chp Mol At Met Ben Thio

23/10 ---- ---- ---- ---- ---- ---- ----

24/10 ---- ---- 0.3 ---- ---- ---- ----

25/10 ---- ---- 0.35 ---- ---- ---- ----

26/10 12.4 ---- 0.4 ---- ---- ---- ----

27/10 1.6 ---- 0.4 ---- ---- ---- ----

28/10 0.53 ---- 0.3 ---- ---- ---- ----

29/10 0.2 ---- 0.15 ---- ---- ---- ----

30/10 0.06 ---- 0.1 ---- ---- ---- ----

31/10 ---- ---- 0.08 ---- ---- ---- ----

19/11 0.08 ---- 42 ---- ---- ---- ----

20/11 ---- ---- 31 ---- 0.06 ---- ----

21/11 ---- ---- 36 ---- 0.1 ---- 0.07

22/11 ---- ---- 23 ---- ---- ---- ----

23/11 ---- ---- 22 ---- ---- ---- ----

24/11 ---- 25 91 0.05 ---- 1.2 ----

25/11 ---- 0.28 59 ---- ---- 2 ----

26/11 ---- 0.17 49 ---- ---- 1.1 ----

27/11 ---- 0.14 46 ---- ---- 1.1 ----

28/11 ---- ---- 46 ---- ---- 0.8 ----

29/11 ---- 0.07 46 ---- ---- 0.8 ----

30/11 ---- 0.05 48 ---- ---- 0.7 ----

3/12 ---- 0.12 24 ---- ---- 2.5 ----

4/12 ---- 0.09 23 0.06 ---- 2 ----

5/12 ---- 0.07 20 ---- 0.08 1.3 ----

6/12 ---- 0.06 18 ---- 0.08 1.1 ----

7/12 ---- ---- 0.04 21 0.12 0.07 1.5

8/12 ---- ---- 0.05 17 0.08 0.05 1.2

9/12 ---- ---- ---- 17 ---- ---- 0.9


Griff. 11

Site Description. M.I.A., Willbriggie. At Guaging Station of 15 farm common Drain OR at Adamsroad supply branch canal.Date: March 1994Sampling: One Litre, amber glass bottle grab sample daily at guage OR at Sturt Supply

branch canal, Adams Road.Tested for: Molinate (Mol), Atrazine (At), Malathion (Mal), Chlorpyrifos (Chp), Bensulfuron

(Ben), Endosulfan (End), Diuron (Di), Bromacil (Bro), Metolachlor (Met),Thiobencarb (Thi), Cypermethrin (Cyp)

Limit of Reporting: 0.05 µg/L for all but Bro (0.5 µg/L), Ben (0.25 µg/L). NOTE: Onlypositives (i.e. > LOR) reported.


Guaging Station

Concentration (µg/L)Date Mal Chp Mol At Met Ben Thio1/3 ---- ---- 0.06 0.24 0.7 0.07 ----2/3 ---- ---- 0.06 0.16 0.37 0.07 ----3/3 ---- ---- 0.07 0.33 0.95 0.06 ----4/3 ---- ---- 0.07 0.45 0.92 0.06 ----5/3 ---- ---- 0.06 0.12 0.1 0.05 ----6/3 ---- ---- 0.06 ---- ---- 0.06 ----7/3 ---- ---- 0.06 ---- ---- 0.09 ----8/3 ---- ---- 0.06 ---- ---- ---- ----9/3 ---- ---- 0.09 ---- ---- ---- ----10/3 ---- ---- 0.08 ---- ---- 0.06 ----11/3 ---- ---- 0.07 ---- ---- ---- ----

Supply

Concentration (µg/L)Date Mal Chp Mol At Met Ben Thio1/3 ---- ---- ---- ---- ---- ---- ----2/3 ---- ---- ---- ---- ---- ---- ----3/3 ---- ---- ---- ---- ---- ---- ----4/3 ---- ---- ---- ---- ---- ---- ----5/3 ---- ---- ---- ---- ---- ---- ----6/3 ---- ---- ---- ---- ---- ---- ----7/3 ---- ---- ---- ---- ---- ---- ----8/3 ---- ---- ---- ---- ---- ---- ----9/3 ---- ---- ---- ---- ---- ---- ----10/3 ---- ---- ---- ---- ---- ---- ----11/3 ---- ---- ---- ---- ---- ---- ----


Griff. 12

Site Description: M.I.A., Willbriggie. At common drain of 5 farm upper catchment(rice/row crops). Nearest farm drain above sampling point was 1.2km (from upstream) and 3.1 km (from Downstream) samplersrespectively.

Date: March 1994Sampling: 24 h composite samples in cooled glass container.Tested for: Molinate (Mol), Atrazine (At), Malathion (Mal), Chlorpyrifos

(Chp), Metolachlor (Met), Bensulfuron (Ben), Endosulfan (End),Diuron (Di), Bromacil (Bro), Cypermethrin, Thiobencarb(Thi)

Limit of Reporting: 0.05 µg/L for all but Bro (0.5 µg/L), Ben (0.25 µg/L)NOTE: Only positives (i.e. > LOR) reported.


Upstream Sampler

Date Concentration (µg/L)

Mol At Met Ben

2/3 0.37 0.53 1.3 0.08

3/3 0.35 1.05 2.7 ----

4/3 0.36 0.9 1.7 0.08

5/3 0.29 0.22 0.3 ----

6/3 0.25 0.08 0.07 ----

7/3 0.28 0.15 0.06 ----

8/3 0.3 0.14 ---- ----

9/3 0.27 0.12 ---- 0.06

10/3 0.26 0.12 ---- ----

11/3 0.23 0.07 ---- ----

Downstream Sampler

Date Concentration (µg/L)

Mol At Met Ben

2/3 0.85 0.54 1.3 0.8

3/3 0.9 1 3 0.08

4/3 0.89 1.1 2.5 ----

5/3 0.78 0.42 0.95 ----

6/3 0.6 0.13 0.43 ----

7/3 0.75 0.21 0.48 ----

8/3 0.75 0.22 0.48 ----

9/3 0.6 0.18 0.38 ----

10/3 0.44 0.13 0.21 ----

11/3 0.45 0.1 0.22 ----


Griff. 13

Site Description: M.I.A., Willbriggie. At individual farm drains of 5 farms with commoncatchment drain. Second Farm Drain B; Third Drain D; Fourth Drain E.

Date: March 1994Sampling: One litre,amber glass bottle grab sample daily when drain is flowing. No samples

taken from Farm C (there was no drainage during monitoring period).Tested for: Molinate (Mol), Atrazine (At), Malathion (Mal), Chlorpyrifos (Chp), Metolachlor

(Met), Bensulfuron (Ben), Endosulfan (End), Diuron (Di), Bromacil (Bro),Thiobencarb (Thi), Cypermethrin (Cyp)

Limit of Reporting: 0.05 µg/L for all but Bro (0.5 µg/L), Ben(0.25 µg/L). Only positives(i.e. > LOR) reported.


Farm A

Date Concentration (µg/L)Mol At Met Ben

1/3 0.15 0.4 0.95 ----2/3 0.17 0.95 3.2 ----3/3 0.21 1.1 2.5 0.084/3 0.23 0.4 0.51 0.085/3 0.29 0.18 ---- ----6/3 0.2 0.24 ---- ----7/3 0.24 0.16 ---- ----8/3 0.22 0.18 ---- ----11/3 0.19 0.19 ---- ----

Farm B

Date Concentration (µg/L)Mol At Met Ben Thi

1/3 ---- ---- ---- ---- 0.122/3 ---- ---- ---- ---- 0.173/3 ---- ---- ---- ---- 0.214/3 0.07 ---- ---- ---- 0.245/3 ---- ---- 0.07 ---- ----6/3 ---- ---- ---- ---- ----7/3 0.07 ---- ---- ---- ----8/3 ---- ---- ---- ---- ----11/3 ---- ---- ---- ---- ----

Farm D


1/3 ---- ---- ---- ---- ----2/3 ---- ---- ---- ---- ----4/3 ---- ---- ---- ---- ----11/3 ---- ---- ---- ---- ----

Farm E.


5/3 ---- ---- ---- ---- ----6/3 ---- ---- ---- ---- ----7/3 ---- ---- ---- ---- ----


Griff. 14Site Description: MIA, maize crop off Mancini Road. First irrigation water after treatment with Atrazine.Date: 11.12.91Sampling: Beaker of water taken at timed intervals at terminus of row irrigation furrow. Two furrowssampled from start to end of first irrigation event. Flow measured by dyeTested for: AtrazineLimit of Reporting: 0.2 µg/LAnalytical method: CSIRO Griffith SPE-HPLC

Elapsed Mancini Road Furrow A.First watering.

Elapsed Mancini Road Furrow B.First watering.

Time Flow Atrazine Load Load Time Flow Atrazine Load Load (min) L/min µg/L µg/min µg/period (min) L/min µg/L µg/min µg/period

0 25.4 23.8 604 ND O 7.3 21.5 158 ND

4 27.5 ND ND ND 2 9.1 19.4 178 335

8 29.0 19.6 569 4691 5 11.1 ND ND ND

12 30.7 ND ND ND 6 12.0 17.2 206 768

15 31.4 12.6 396 3376 8 12.5 ND ND ND

18 35.2 ND ND ND 9 13.3 15.3 203 614

21 34.7 12.1 420 2449 13 14.4 ND ND ND

25 35.7 ND ND ND 15 14.8 12.9 191 1182

28 37.2 10.4 387 2825 17 15.4 ND ND ND

31 37.2 ND ND ND 19 15.6 12 187 756

32 38.8 10.5 408 1589 22 16.8 ND ND ND

35 38.8 ND ND ND 24 16.8 11.1 186 933

38 38.3 8.4 321 2187 26 16.8 ND ND ND

40 40.6 ND ND ND 29 17.5 10.3 181 917

43 40.6 8.9 361 1707 33 19.0 ND ND ND

45 41.9 ND ND ND 34 19.0 9.7 185 913

47 43.3 8 346 1415 37 20.0 ND ND ND

49 44.0 ND ND ND 40 20.7 9.7 200 1155

52 43.3 8.5 368 1785 43 21.1 ND ND ND

55 44.7 ND ND ND 45 21.8 9.2 201 1003

58 44.0 6.9 304 2014 48 22.3 ND ND ND

63 44.0 ND ND ND 50 23.1 8.9 206 1016

66 40.0 7.6 304 2430 54 24.8 ND ND ND

70 44.7 ND ND ND 56 24.8 9.5 235 1323

73 43.3 6.7 290 2079 59 24.8 ND ND ND

76 43.3 ND ND ND 63 26.9 8.8 237 1652

80 44.7 10.2 456 2612 67 27.6 ND ND ND

85 45.5 ND ND ND 73 25.8 7.5 193 2150

89 45.5 7.3 332 3549 76 28.4 ND ND ND

93 43.3 ND ND ND 80 29.7 7.1 211 1415

96 42.6 7.6 324 2296 87 29.7 ND ND ND

101 44.7 ND ND ND 92 30.6 6.2 190 2404

105 44.0 7 308 2842 97 30.6 ND ND ND

111 40.6 ND ND ND 99 30.6 5.8 177 1285

115 38.8 7.1 276 2918 106 30.6 ND ND ND

123 38.3 ND ND ND 109 29.7 3.8 113 1452

127 38.3 6.5 249 3146 120 29.2 ND ND ND

135 40.6 ND ND ND 129 29.7 4.7 140 2526

138 40.6 4.3 175 2328 142 27.6 3.5 97 1536

144 41.9 ND ND ND 151 31.5 4.3 136 1045

153 43.3 ND ND ND 165 24.8 3.7 92 1590

160 44.7 5.6 251 4677 174 24.2 3.7 89 815

172 45.5 5 228 2869 183 23.1 3.4 79 756

180 45.5 6 273 2003 193 22.8 3.2 73 757

190 40.6 4.6 187 2300 201 22.8 3.8 87 638

201 36.2 4.9 177 2002 212 22.8 3.1 71 864

210 49.8 5.1 254 1941 222 23.1 3.2 74 723

228 47.1 6.2 292 4917 230 23.6 2.9 69 570

239 51.8 6.1 316 3344 240 23.6 3.7 87 780

251 48.9 6.1 298 3684 249 24.8 2.9 72 717

262 48.0 5.1 245 2987 259 24.8 3.1 77 743

272 48.0 3.9 187 2160

282 48.0 ND ND ND

296 47.1 5.1 240 5132

306 48.0 4.6 221 2306

318 48.0 4.3 206 2563 Total load (mg) for furrow A = 107 mg

328 47.1 4.4 207 2069

338 47.1 4.2 198 2027 Total load (mg) for furrow B = 35.4 mg

346 47.1 4.5 212 1641

355 44.7 3.8 170 1720

365 47.1 4.2 198 1840

377 48.0 3.4 163 2167

385 49.8 3.6 179 1370

394 50.8 3.1 157 1515

404 46.3 3.4 157 1574


Griff. 15

Site Description: MIA, maize crop off Wilga Road. First irrigation water after trearment withatrazine.Date: 24.Decmber, 1991; 17 January, 1992; 21 February, 1992Sampling: Beaker of water taken at timed intervals at terminus of row irrigation furrow. Twofurrows sampled from start to end of first irrigation event. Flow measured by dye.Tested for: Atrazine.Limit of Reporting: 0.2 µg/LAnalytical method: CSIRO Griffith SPE-HPLC

Load per period = av. concentration (µg/L) * flow per periodNOTE 1: period = elapsed time between each sampleNOTE 2: average concentration (µg/L) = conc. at a particular elapsed time + conc. at theprevious elapsed time divided by two.

Elapsed Wilga Road Furrow A.First watering.

Elapsed Wilga Road Furrow B.First watering.

Time Flow Atrazine Load Load Time Flow Atrazine Load Load(min) L/min µg/L µg/min µg/period (min) L/min µg/L µg/min µg/period

0 0.97 56.8 55.3 ND 0 0.91 135 122.9 ND

3 1.53 ND ND ND 5 1.03 107.5 110.4 583

6 1.23 145.2 178.4 701 8 0.91 98.9 89.8 300

10 1.29 120.9 155.8 668 14 0.94 113.6 106.5 589

14 1.13 99.4 112.1 536 18 0.95 ND ND ND

19 1.11 93.5 103.6 539 24 0.96 73.2 70.5 885

25 1.08 97.7 105.6 628 30 1.02 ND ND ND

27 1.04 ND ND ND 32 1.07 64.6 69.1 558

30 0.98 84.1 82.8 471 33 1.15 ND ND ND

32 1.00 ND ND ND 43 1.15 57.2 65.5 741

35 1.08 ND ND ND 49 1.25 ND ND ND

38 1.46 85.9 125.1 831 61 1.72 56 96.1 1455

43 2.82 ND ND ND 77 1.69 44.3 74.9 1368

49 2.75 68.7 188.9 1727 92 3.90 ND ND ND

56 2.47 ND ND ND 107 4.80 50.8 243.6 4777

59 2.57 60.9 156.7 1728 123 4.96 52.8 261.9 4044

68 2.56 ND ND ND 158 6.73 43.4 292.2 9696

73 2.65 50.6 134.2 2036 179 7.14 ND ND ND

83 2.75 ND ND ND 212 7.59 26.2 198.8 13257

88 3.10 50.8 157.5 2187 239 8.57 ND ND ND

100 3.22 ND ND ND 256 9.68 24.4 236.3 9571

111 3.63 ND ND ND 285 10.59 ND ND ND

114 3.58 41.9 150.2 4000 302 11.34 27.3 309.5 12553

126 3.96 ND ND ND 325 11.47 25.5 292.4 6922

142 4.61 43.9 202.4 4936 345 12.20 ND ND ND

161 5.98 59.9 358.5 5328 360 12.25 25.4 311.1 10561

181 7.06 56.2 396.6 7551 385 12.98 24.5 318.0 7864

197 7.03 ND ND ND 405 13.74 ND ND ND

212 7.98 50.5 402.7 12390 420 13.20 22.4 295.8 10740

247 9.38 34.0 319.0 12630 439 13.38 25.6 342.5 6063

268 9.67 ND ND ND 446 13.50 24.9 336.0 2375

301 11.56 29.3 338.6 17757 455 13.56 25.1 340.2 3043

328 11.52 ND ND ND 465 13.32 23.5 313.0 3266

345 12.04 27.0 325.0 14601 477 11.42 22.5 257.0 3420

374 13.87 ND ND ND 486 9.56 21.5 205.6 2082

391 13.63 25.1 342.2 15345 497 7.37 20.1 148.1 1945

414 16.70 34.2 571.2 10504 506 6.20 17.7 109.7 1160

434 19.57 ND ND ND 517 5.11 17.2 87.9 1087

448 21.55 23.5 506.5 18321 527 4.07 17.2 69.9 789

468 22.46 27.9 626.8 11333 536 3.35 17.2 57.6 574

494 22.46 ND ND ND 547 2.72 17.5 47.7 579

508 22.79 32.1 731.4 27164 Total(mg)

122.8

528 22.31 31.9 711.6 14430

535 22.00 37.3 820.6 5363

544 21.70 ND ND ND

554 21.13 29.6 625.3 13736

566 17.92 26.0 466.0 6548 ---- = below limit of reporting (LOR);

575 14.37 24.3 349.2 3668 ND = not determined

586 10.74 21.0 225.6 3161

595 7.58 27.4 207.6 1949

606 5.45 23.0 125.4 1832

616 3.96 19.3 76.5 1009

625 2.90 19.9 57.7 604

636 2.03 17.8 36.1 516

Total(mg)

226.7

Griff. 15 cont.

Elapsed Wilga Road Furrow A.Second watering.

Elapsed Wilga Road Furrow B. Secondwatering.

Time Flow Atrazine Load Load Time Flow Atrazine Load Load(min) L/min ug/L ug/min ug/period (min) L/Min ug/L ug/min ug/period

0.00 10.00 11.40 114.0 ND 0.00 12.02 16.20 194.8 ND

6.00 11.05 7.70 85.1 597 2.00 11.35 11.40 129.4 324

9.00 11.92 7.40 88.2 260 8.00 11.93 9.30 110.9 721

16.00 12.15 7.60 92.4 632 11.00 12.57 8.60 108.1 329

25.00 14.17 6.90 97.8 856 17.00 13.84 ND ND ND

30.00 15.12 6.20 93.7 479 23.00 14.85 6.60 98.0 1237

36.00 16.37 5.90 96.6 571 30.00 16.03 6.20 99.4 691

42.00 17.46 6.00 104.8 604 37.00 17.02 5.90 100.4 699

50.00 18.37 4.10 75.3 720 42.00 18.59 5.70 106.0 516

60.00 19.75 ND ND ND 52.00 19.42 5.60 108.8 1074

65.00 21.64 5.40 116.9 1442 60.00 19.68 ND ND ND

75.00 21.64 5.80 125.5 1212 65.00 20.47 5.60 114.6 1452

87.00 22.73 5.60 127.3 1517 75.00 22.61 5.60 126.6 1206

98.00 23.94 7.50 179.5 1688 87.00 24.84 ND ND ND

109.00 25.28 ND ND ND 99.00 24.84 ND ND ND

124.00 25.69 4.80 123.3 3937 109.00 26.35 ND ND ND

135.00 26.78 ND ND ND 122.00 28.06 ND ND ND

146.00 27.72 3.50 97.0 2424 135.00 ND ND ND ND

155.00 26.12 6.10 159.3 1153 145.00 29.13 ND ND ND

165.00 22.73 4.60 104.6 1319 155.00 29.71 5.10 151.5 11125

172.00 19.39 4.40 85.3 665 165.00 28.06 5.10 143.1 1473

179.00 15.12 4.30 65.0 526 173.00 24.84 4.70 116.7 1039

188.00 12.25 4.30 52.7 530 180.00 24.84 4.80 119.2 826

195.00 9.63 4.20 40.5 326 187.00 16.47 5.00 82.3 705

201.00 8.08 4.10 33.1 221 195.00 13.59 4.90 66.6 596

208.00 7.02 4.40 30.9 224 200.00 12.12 5.20 63.0 324

214.00 6.26 ND ND ND 207.00 10.27 5.20 53.4 408

222.00 5.68 3.90 22.2 371 213.00 9.07 5.60 50.8 313

227.00 5.45 4.40 24.0 115 221.00 8.51 5.90 50.2 404

Total(mg)

22.4 227.00 7.75 6.60 51.1 304

233.00 44.00 7.50 309

241.00 51.53 7.40 384

247.00 34.79 8.40 274

Total(mg)

26.7

Elapsed Wilga Road Furrow A . Fourthwatering

Elapsed Wilga Road Furrow B . Fourthwatering.

Time Flow Atrazine Load Load Time Flow Atrazine Load Load(min) L/min ug/L ug/min ug/period (min) L/min ug/L ug/min ug/period

0.00 2.01 3.36 6.74 ND 0.00 8.43 1.26 10.62 ND

6.00 1.93 1.54 2.96 28.90 4.00 20.06 0.69 13.84 55.56

15.00 2.86 1.26 3.61 30.18 11.00 19.81 0.57 11.29 87.93

21.00 3.30 1.04 3.43 21.27 20.00 14.41 0.77 11.10 103.18

30.00 4.01 0.92 3.69 32.26 26.00 12.19 0.76 9.27 61.05

38.00 3.92 0.81 3.17 27.44 34.00 10.71 0.79 8.46 71.00

47.00 3.93 0.60 2.36 24.91 42.00 10.53 0.80 8.43 67.55

54.00 3.79 0.60 2.27 16.21 50.00 10.33 0.68 7.02 61.74

66.00 3.93 0.48 1.89 25.01 61.00 9.78 0.62 6.07 71.89

76.00 4.25 0.48 2.04 19.65 71.00 10.23 0.86 8.79 74.04

96.00 4.67 0.37 1.73 37.94 92.00 9.61 0.51 4.90 142.64

109.00 4.76 0.39 1.85 23.29 105.00 9.91 0.63 6.24 72.29

125.00 4.88 0.33 1.61 27.74 117.00 10.39 0.62 6.44 76.12

140.00 5.15 0.26 1.34 22.18 138.00 9.27 0.64 5.93 130.07

154.00 5.03 0.37 1.86 22.44 149.00 10.53 0.37 3.90 55.00

165.00 5.30 ND ND ND 160.00 9.64 0.72 6.94 60.45

177.00 3.92 0.37 1.45 20.46 173.00 7.93 0.73 5.79 82.75

185.00 3.57 0.15 0.54 7.78 185.00 5.02 0.53 2.66 48.95

195.00 3.25 0.37 1.20 8.86 194.00 2.96 0.77 2.28 23.36

207.00 3.05 0.26 0.79 11.90 209.00 1.88 0.90 1.69 30.31

Total(mg)

0.41 Total(mg)

1.38

---- = below limit of reporting (LOR); ND = not determinedLoad per period = av. load (µg/min) * elapsed time per periodNOTE 1: period = elapsed time between each sampleNOTE 2: average concentration (µg/L) = conc. at a particular elapsed time + conc. at the previouselapsed time divided by two.

Griff. 16

Site Description. MIA, Merungle Hill, surface runoff from horticulture (citrus). Irrigationof a 3.56 hectare orchard. First irrigation after application of bromacil and diuron butfollowing a substantial (~ 20 mm) rainfall event *.Date: 27.11.92Sampling: 50 mL sample in glass syringe taken at timed intervals from v-notch flume.Tested for: Bromacil (Bro), Diuron (Di).Limit of Reporting: 0.2 µg/LAnalytical method: CSIRO Griffith SPE-HPLC

NOTE * The rainfall event (~ 20 mm), which occurred after pesticide application butbefore the first irrigation, may have caused some pesticide runoff. The actualfirst irrigation could therefore be thought of as the second irrigation receivedby the crop. Under these circumstances the concentrations given above would beunderestimates for a first irrigation runoff event.

NominalSample Time ** Bromacil Diuron

No. (min) µg/L µg/L1 5 14.6 19.62 10 11.1 16.43 15 9.4 164 20 10.3 13.55 25 2.4 8.96 30 2.2 1.27 40 2.3 8.88 50 7.2 11.19 60 4.3 10.2

10 80 9.4 10.411 100 8.8 10.712 120 8.2 10.413 140 7.9 9.814 160 8.6 10.415 180 8.6 9.916 200 10.3 10.717 220 9.8 11.218 240 8.9 9.619 260 8.8 8.9

Av µg/L 8.1 10.9S.D. 7.7 10.5

NOTE ** Sampling times were times suggested by CSIRO while samples were taken by NSWDepartment of Agriculture. Unfortunately, records regarding the actual timesamples were taken have been lost.

Discharge (L) *** over260 (min) samplingperiod

Total Discharge (L) ***over irrigation period

15000 35000

NOTE *** Discharge and total discharge values are correct.

Griff. 17

Site Description: MIA, Griffith tile drainage (TD) from horticultural area. Sampling pointscoincide with farm sump pumpouts used by NSW DLWC in their 10 year salinity check programme.Date: TD 1 (1-23) = 14 January, 1992 ; (25-50) = 21 January, 1992

TD 2 C = 18 May, 1992; TD 3 D = 13 August, 1992NOTE: the number 24 was not used in the sampling regime

Sampling: 50 mL sample in glass syringe taken at each farm per collection.Sample Collected using a stainless steel bucket at pump out point.

Tested for: Bromacil (Bro), Diuron (Di).Limit of Reporting: 0.5 µg/L Bromacil, 0.05 µg/L Diuron

NOTE: Only positives (i.e. > LOR) reportedAnalytical method: CSIRO Griffith LLE-GC/MS checked SPE-HPLC

BROMACILTD 1 TD 2 C TD 3 D Jan/Aug

Bromacil Volume Average Average Bromacil Volume Average Average Bromacil TotalSample GC/MS Pumped Bromacil Load GC/MS Pumped Bromacil Load GC/MS LoadNo. µg/L (ML) µg/L grms µg/L (ML) µg/L grms µg/L grms

1 ---- 5.62 ---- ND ---- 1.99 ---- ND ---- ND

2 ---- 14.17 ---- ND ---- 1.90 ---- ND ---- ND

3 ---- 13.46 ---- ND ---- 1.19 ---- ND ---- ND

4 ---- 6.40 ---- ND ---- 0.27 ---- ND ---- ND

5 ---- 1.55 ---- ND ---- 1.08 ---- ND ---- ND

6 ---- 11.63 ---- ND ---- 1.33 ---- ND ---- ND

7 ---- 8.03 ---- ND ---- 0.09 ---- ND ---- ND

8 ---- ND ---- ND ---- ND ---- ND ---- ND

9 0.5 8.87 0.50 4.43 0.5 0.32 5.75 1.81 11 6.24

10 0.5 2.67 1.75 4.68 3 0.04 2.5 0.10 2 4.78

11 ---- 7.82 ---- ND ---- 0.73 ---- ND ---- ND

12 ---- 85.27 ---- ND ---- ND ND ND ND ND

13 ---- 2.99 ---- ND ---- 0.17 ---- ND ---- ND

14 ---- 16.47 ---- ND ---- 0.56 ---- ND ---- ND

15 ---- 13.95 ---- ND ---- 3.54 ---- ND ---- ND

16 ---- 4.84 ---- ND ---- 0.22 ---- ND ---- ND

17 ---- 5.17 ---- ND ---- ND ---- ND ---- ND

18 ---- 4.53 ---- ND ---- 0.33 0.145 0.05 0.29 0.05

19 ---- 6.73 ---- ND ---- 0.77 ---- ND ---- ND

20 ---- 5.49 ---- ND ---- 0.85 ---- ND ---- ND

21 0.55 5.84 0.78 4.53 1 0.37 0.5 0.19 ---- 4.71

22 1 8.33 1.25 10.41 1.5 1.36 2.3 3.13 3.1 13.54

23 ---- 14.30 0.40 5.72 0.8 1.08 0.4 0.43 ---- 6.15

25 0.55 9.06 0.65 5.89 0.75 2.89 0.65 1.88 0.55 7.77

26 1.7 4.91 1.10 5.40 0.5 1.75 0.25 0.44 ---- 5.84

27 ---- 5.30 2.50 13.24 5 1.68 2.5 4.21 ---- 17.45

28 ---- 5.83 ---- ND ---- 0.25 ---- ND ---- ND

29 ---- 5.31 ---- ND ---- 0.26 ---- ND ---- ND

30 1.45 4.26 1.23 5.22 1 1.54 1.25 1.92 1.5 7.14

31 ---- 31.03 ---- ND ---- 6.64 ---- ND ---- ND

32 ---- 7.54 ---- ND ---- 0.03 ---- ND ---- ND

33 ---- 1.64 ---- ND ---- 0.26 ---- ND ---- ND

34 ---- 10.05 ---- ND ---- 2.27 ---- ND ---- ND

35 ---- 2.10 0.50 1.05 1 1.28 0.5 0.64 ---- 1.69

36 0.69 3.38 0.35 1.16 ---- 1.38 0.95 1.31 1.9 2.47

37 ---- 2.57 0.25 0.64 0.5 0.62 0.25 0.16 ---- 0.80

38 ---- 33.13 ---- ND ---- 4.41 ---- ND ---- ND

39 ---- 71.31 ---- ND ---- 12.61 ---- ND ---- ND

40 3.9 8.97 3.00 26.92 2.1 14.77 3.5 51.68 4.9 78.60

41 1.64 7.68 0.82 6.30 ---- 0.03 2 0.06 4 6.36

42 ---- 12.57 ---- ND ---- 0.57 0.6 0.34 1.2 0.34

43 ---- 0.51 ---- ND ---- 0.05 ---- ND ---- ND

44 ---- 30.13 0.25 7.53 0.5 2.91 0.25 0.73 ---- 8.26

45 ---- 4.20 ---- ND ---- 0.10 ---- ND ---- ND

46 0.83 9.70 1.57 15.18 2.3 1.42 1.65 2.34 1 17.52

47 ---- 5.63 ---- ND ---- 0.43 ---- ND ---- ND

48 ---- 4.82 ---- ND ---- 0.57 ---- ND ---- ND

49 0.5 2.06 1.05 2.17 1.6 0.08 1.05 0.08 0.5 2.25

50 ---- 3.26 ---- ND ---- 0.30 ---- ND ---- ND

---- = below limit of reporting (LOR); ND = not determinedAverage Load (grms) = volume pumped (ML) * average concentration (µg/L)

NOTE 1: average concentration = conc. at two consecutive sampling dates divided by 2

Griff. 17 continued.

DIURONTD 1 TD 2 C TD 3 D Jan/AugDiuron Volume Average Average Diuron Volume Average Average GC/MS Total

Sample GC/MS Pumped Diuron Load GC/MS Pumped Diuron Load Diuron LoadNo. µg/L (ML) ug/L grms µg/L (ML) µg/L grms µg/L grms

1 ---- 5.62 ---- ND ---- 1.99 ---- ND ---- ND

2 ---- 14.17 ---- ND ---- 1.90 ---- ND ---- ND

3 ---- 13.46 ---- ND ---- 1.19 ---- ND ---- ND

4 0.74 6.40 0.87 5.57 1.00 0.27 0.95 0.26 0.90 5.82

5 ---- 1.55 ---- ND ---- 1.08 ---- ND ---- ND

6 ---- 11.63 ---- ND ---- 1.33 ---- ND ---- ND

7 ---- 8.03 ---- ND ---- 0.09 ---- ND ---- ND

8 ---- ND 0.04 ND 0.08 ND 0.04 ND ---- ND

9 0.12 8.87 0.15 1.33 0.18 0.32 3.34 1.05 6.50 2.38

10 2.90 2.67 1.55 4.13 0.19 0.04 0.16 0.01 0.12 4.14

11 ---- 7.82 0.10 0.74 0.19 0.73 14.00 10.20 27.80 10.95

12 ---- 85.27 ---- ND ---- ND ND ND ND ND

13 ---- 2.99 ---- ND ---- 0.17 0.07 0.01 0.14 0.01

14 ---- 16.47 ---- ND ---- 0.56 ---- ND ---- ND

15 ---- 13.95 ---- ND ---- 3.54 ---- ND ---- ND

16 ---- 4.84 ---- ND ---- 0.22 ---- ND ---- ND

17 ---- 5.17 ---- ND ---- ND ---- ND ---- ND

18 ---- 4.53 ---- ND ---- 0.33 ---- ND ---- ND

19 ---- 6.73 ---- ND ---- 0.77 ---- ND ---- ND

20 ---- 5.49 ---- ND ---- 0.85 ---- ND ---- ND

21 0.42 5.84 1.41 8.23 2.40 0.37 1.64 0.61 0.87 8.84

22 ---- 8.33 0.20 1.67 0.40 1.36 0.38 0.52 0.36 2.18

23 ---- 14.30 0.70 10.01 1.40 1.08 0.70 0.76 ---- 10.77

25 0.14 9.06 0.07 0.63 0.00 2.89 0.00 0.00 ---- 0.63

26 0.52 4.91 0.30 1.47 0.08 1.75 0.04 0.07 ---- 1.54

27 ---- 5.30 0.55 2.91 1.10 1.68 0.55 0.93 ---- 3.84

28 ---- 5.83 ---- ND ---- 0.25 ---- ND ---- ND

29 ---- 5.31 ---- ND ---- 0.26 ---- ND ---- ND

30 0.20 4.26 0.14 0.58 0.07 1.54 0.09 0.13 0.10 0.71

31 ---- 31.03 ---- ND ---- 6.64 ---- ND ---- ND

32 ---- 7.54 ---- ND ---- 0.03 ---- ND ---- ND

33 ---- 1.64 0.03 0.05 0.06 0.26 0.11 0.03 0.16 0.08

34 ---- 10.05 ---- ND ---- 2.27 ---- ND ---- ND

35 ---- 2.10 ---- ND ---- 1.28 0.11 0.13 0.21 0.13

36 0.60 3.38 0.58 1.94 0.55 1.38 1.08 1.48 1.60 3.42

37 ---- 2.57 0.04 0.09 0.07 0.62 0.84 0.52 1.60 0.61

38 0.30 33.13 0.65 21.53 1.00 4.41 1.10 4.85 1.20 26.38

39 0.17 71.31 0.16 11.41 0.15 12.61 0.08 0.95 0.00 12.36

40 3.10 8.97 2.05 18.39 1.00 14.77 1.10 16.24 1.20 34.64

41 0.08 7.68 0.04 0.31 0.00 0.03 0.15 0.00 0.30 0.31

42 ---- 12.57 ---- ND ---- 0.57 ---- ND ---- ND

43 ---- 0.51 ---- ND ---- 0.05 ---- ND ---- ND

44 0.55 30.13 0.68 20.34 0.80 2.91 0.58 1.69 0.36 22.03

45 ---- 4.20 ND ND ---- 0.10 ---- ND ---- ND

46 0.13 9.70 0.32 3.05 0.50 1.42 0.25 0.36 ---- 3.41

47 ---- 5.63 ---- ND ---- 0.43 0.07 0.03 0.14 0.03

48 ---- 4.82 ---- ND ---- 0.57 0.03 0.02 0.06 0.02

49 0.20 2.06 0.25 0.52 0.30 0.08 0.25 0.02 0.19 0.53

50 ---- 3.26 0.03 0.10 0.06 0.30 0.08 0.02 0.10 0.12

---- = below limit of reporting (LOR); ND = not determinedAverage Load (grms) = volume pumped (ML) * average concentration (µg/L)

NOTE 1: average concentration = conc. at two consecutive sampling dates divided by 2

Griff. 18

Site Description: MIA, Griffith tile drainage (TD) from horticultural area. Sampling pointscoincide with farm sump pumpouts used by NSW DLWC in their 10 year salinity check programme.Date: Each tile drain sampled on 8 occasions during May/June, 1992.

A = 12 May; B = 14 May; C = 18 May; D = 21 MayE = 25 May; F = 28 May; G = 1 May; H = 4 June

Sampling: 50 mL sample in glass syringe taken at each farm per collection.Sample Collected using a stainless steel bucket at pump out point.

Tested for: DiuronLimit of Reporting: 0.005 µg/L

NOTE: Only positives (i.e. > LOR) reportedAnalytical method: ELISA (CSIRO Division of Plant Industry, Sydney)

Load (mg) = ML pumped * av. (first conc (µg/L) + second conc (µg/L)).

Volume Load Volume Load Volume LoadA B Pumped Pumped C Pumped Pumped D Pumped Pumped

ELISA ELISA Between Between ELISA Between Between ELISA Between BetweenSample Diuron Diuron A and B A and B Diuron B and C B and C Diuron C and D C and DNo. ug/L ug/L ML mg ug/L ML mg ug/L ML mg

1 ---- 0.010 0.009 0.05 ---- 0.144 0.72 ---- 0.252 ND

2 ---- 0.030 0.067 1.00 ---- 0.164 2.46 0.020 0.252 2.52

3 ---- 0.010 0.049 0.25 ---- 0.110 0.55 ---- 0.150 ND

4 ND 0.010 ND ND 1.310 0.007 4.62 1.010 0.007 8.12

5 ---- 0.010 ND ND 0.020 ND ND 0.010 0.004 0.06

6 ---- 0.010 0.059 0.30 0.010 0.142 1.42 0.010 0.196 1.96

7 ND ---- ND ND 0.010 0.056 0.28 0.010 0.065 0.65

8 0.010 0.010 ND ND 0.010 ND ND 0.010 ND ND

9 0.040 0.230 0.036 4.86 0.010 0.036 4.32 0.280 0.036 5.22

10 0.170 0.210 0.017 3.27 0.134 0.017 2.96 0.260 0.017 3.39

11 0.120 ---- 0.029 1.74 0.153 0.070 5.36 0.210 0.102 18.51

12 ---- 0.040 ND ND 0.045 ND ND 0.010 3.202 88.06

13 ND 0.020 ND ND 0.007 ND ND ---- ND ND

14 ND ---- ND ND ---- 0.017 ND 0.010 0.186 0.93

15 ND 0.010 ND ND 0.009 0.327 3.11 0.010 0.344 3.27

16 ND ---- ND ND 0.021 ND ND 0.010 ND ND

17 ---- 0.010 ND ND ---- ND ND ---- ND ND

18 ---- 0.110 0.007 0.39 0.003 0.025 1.41 ---- 0.057 0.09

19 0.006 ---- 0.020 0.06 0.007 0.094 0.33 ---- 0.094 0.33

20 0.440 ---- 0.018 3.96 ---- 0.054 ND ---- 0.072 ND

21 ND 0.060 ND ND 1.640 0.045 38.25 1.540 0.077 122.43

22 0.280 0.460 0.052 19.24 0.473 0.203 94.70 0.380 0.286 121.98

23 ---- ND 0.128 ND 0.944 0.256 120.83 0.240 0.266 157.47

25 0.110 0.090 0.104 10.40 0.140 0.264 30.36 0.120 0.374 48.62

26 0.050 0.080 0.041 2.67 0.240 0.145 23.20 0.130 0.226 41.81

27 ---- 0.010 0.014 0.07 0.230 0.082 9.84 0.120 0.482 84.35

28 ---- 0.140 0.014 0.98 ---- 0.032 2.24 0.010 0.041 0.21

29 0.010 0.020 0.004 0.06 ---- 0.006 0.06 0.010 0.006 0.03

30 0.910 0.300 0.083 50.22 0.110 0.209 42.85 0.070 0.292 26.28

31 ---- ---- 0.138 ND 0.010 0.921 4.61 0.010 1.083 10.83

32 ND ---- ND ND 0.012 0.002 0.01 ---- 0.004 0.02

33 ---- 0.110 0.009 0.50 0.207 0.025 3.99 0.100 0.036 5.53

34 ---- 0.020 0.061 0.61 0.038 0.166 4.80 0.010 0.243 5.83

35 0.090 0.130 0.014 1.58 0.030 0.014 1.15 0.020 0.014 0.36

36 1.200 0.120 0.034 22.57 0.909 0.099 50.94 0.520 0.151 108.03

37 0.060 0.080 0.038 2.65 0.110 0.079 7.53 0.100 0.110 11.58

38 0.900 0.650 0.470 364.25 1.030 0.963 808.92 0.860 1.292 1220.94

39 0.130 0.200 0.514 84.81 0.040 2.311 277.32 0.150 3.890 369.55

40 0.640 ND 0.169 54.08 1.110 0.268 148.74 0.670 0.318 283.02

41 ---- 0.010 0.028 0.14 0.008 0.035 0.31 ---- 0.035 0.14

42 ND 0.030 0.032 ND 0.033 0.076 2.38 0.030 0.104 3.29

43 ---- ---- ND ND 0.002 ND ND ---- 0.002 ND

44 0.550 1.100 0.262 216.23 1.110 0.835 922.12 0.650 1.176 1034.79

45 ---- 0.020 0.004 0.04 0.020 0.008 0.16 0.040 0.012 0.36

46 2.240 ND 0.153 171.36 0.239 0.373 44.53 0.250 0.430 105.18

47 0.010 ND 0.016 ND 0.010 0.018 0.09 0.050 0.022 0.66

48 ---- 0.680 0.070 23.87 ND 0.151 51.41 0.060 0.261 7.83

49 0.430 0.130 0.004 1.01 0.300 0.009 1.94 0.160 0.014 3.31

50 ---- 0.060 0.013 ND 0.010 0.040 1.39 0.090 0.063 3.15


Griff. 18 continued.

Volume Volume Volume VolumeE Pumped F Pumped G Pumped H Pumped

ELISA Between Load ELISA Between Load ELISA Between Load ELISA Between LoadSample Diuron D and E Pumped Diuron E and F Pumped Diuron F and G Pumped Diuron G and H Pumped

No. µg/L ML mg µg/L ML mg µg/L ML mg µg/L ML mg

1 ---- ND ND ---- 0.596 ND ---- 0.601 ND ---- 0.689 ND

2 ---- 0.365 3.65 ---- 0.419 ND ---- 0.558 ND 0.010 0.562 2.81

3 ---- 0.204 ND ---- 0.227 ND ---- 0.313 ND ND 0.335 ND

4 0.540 0.014 10.85 0.640 0.014 8.26 1.590 0.076 84.74 ND 0.104 ND

5 ---- 0.004 0.02 ---- 0.004 ND ---- 0.004 ND ---- 0.017 ND

6 ---- 0.268 1.34 0.120 0.313 18.79 ---- 0.380 22.79 ---- 0.432 ND

7 ---- 0.065 0.33 ---- 0.065 ND 0.010 0.065 0.33 ---- 0.097 0.49

8 0.010 ND ND ---- ND ND 0.010 ND ND 0.010 ND ND

9 0.090 0.090 16.65 ND 0.144 ND 0.310 0.148 22.88 0.300 0.148 45.02

10 0.120 0.017 3.27 0.170 0.051 7.42 0.100 0.058 7.84 0.140 0.065 7.80

11 0.200 0.125 25.63 0.180 0.145 27.55 0.170 0.165 28.88 0.520 0.633 218.39

12 0.010 3.202 32.02 0.030 7.357 147.13 0.020 9.157 228.92 0.010 10.908 163.62

13 ---- 0.002 ND ---- 0.002 ND 0.010 0.015 0.08 ---- 0.040 0.20

14 0.010 0.258 2.58 0.010 0.355 3.55 0.020 0.355 5.33 0.010 0.355 5.33

15 0.010 0.344 3.44 ---- 0.596 2.98 ND 0.772 ND 0.010 0.913 4.57

16 ---- ND ND ---- 0.182 ND ---- 0.216 ND ---- 0.216 ND

17 ---- ND ND 0.120 ND ND ---- ND ND ---- 0.000 ND

18 ---- 0.057 ND ---- 0.068 ND ---- 0.081 ND ---- 0.094 ND

19 ---- 0.130 ND ---- 0.166 ND ---- 0.202 ND ---- 0.418 ND

20 ---- 0.108 ND ---- 0.140 ND ---- 0.180 ND ---- 0.198 ND

21 1.100 0.115 151.80 1.520 0.140 183.40 1.350 0.171 245.39 1.090 0.191 233.02

22 0.280 0.398 131.34 0.370 0.607 197.28 ND 0.607 ND 0.300 0.668 100.20

23 ---- 0.335 40.20 0.200 0.376 37.60 0.220 0.404 84.84 0.230 0.473 106.43

25 0.090 0.518 54.39 0.150 0.662 79.44 0.110 0.910 118.30 0.100 1.063 111.62

26 0.130 0.307 39.91 0.180 0.379 58.75 0.140 0.600 96.00 0.140 0.688 96.32

27 0.100 0.676 74.36 0.070 0.777 66.05 0.100 0.881 74.89 0.090 0.953 90.54

28 0.030 0.055 1.10 0.010 0.064 1.28 0.030 0.077 1.54 0.010 0.084 1.68

29 0.010 0.006 0.06 0.070 0.006 0.24 ---- 0.006 0.21 0.020 0.076 0.76

30 0.110 0.391 35.19 0.090 0.461 46.10 0.080 0.540 45.90 0.090 0.605 51.43

31 ---- 2.552 12.76 0.040 2.993 59.86 0.010 3.707 92.68 ---- 3.979 19.90

32 ---- 0.004 ND 0.880 0.004 1.76 ---- 0.008 3.52 ---- 0.012 ND

33 0.130 0.052 6.00 0.150 0.065 9.07 0.170 0.079 12.67 0.180 0.092 16.07

34 0.010 0.344 3.44 0.070 0.427 17.06 0.060 0.515 33.46 0.020 0.589 23.54

35 0.030 0.014 0.36 0.150 0.016 1.46 0.310 0.144 33.12 0.160 0.144 33.84

36 0.400 0.225 103.50 0.570 0.283 137.06 0.470 0.353 183.46 0.520 0.414 204.93

37 0.270 0.114 21.03 0.140 0.176 36.04 0.130 0.283 38.16 0.180 0.334 51.83

38 0.870 1.692 1463.58 0.940 1.973 1785.57 0.690 2.286 1863.09 0.810 2.540 1905.00

39 0.110 4.566 593.58 0.150 5.300 689.00 0.120 5.848 789.48 0.150 6.282 848.07

40 0.700 0.383 262.36 0.470 0.430 251.55 1.870 2.534 2964.78 2.520 4.383 9620.69

41 0.030 0.048 0.72 0.030 0.048 1.45 0.140 0.052 4.39 0.070 0.055 5.79

42 0.050 0.135 5.40 0.040 0.401 18.06 0.040 0.454 18.14 0.040 0.491 19.66

43 0.010 0.022 0.11 ---- 0.031 0.15 ---- 0.036 ND ---- 0.040 ND

44 0.560 1.459 882.51 0.720 1.645 1052.74 0.740 1.848 1349.26 0.630 2.004 1372.40

45 0.040 0.016 0.64 0.030 0.020 0.70 0.050 0.024 0.96 0.030 0.028 1.12

46 0.220 0.430 101.10 0.860 0.578 312.01 0.900 0.722 635.18 0.810 0.835 714.10

47 0.070 0.024 1.44 0.080 0.024 1.80 0.120 0.026 2.60 0.120 0.026 3.12

48 0.030 0.265 11.91 0.010 0.297 5.94 0.040 0.328 8.19 0.020 0.580 17.39

49 0.180 0.018 3.06 0.360 0.022 5.83 ND 0.023 ND 0.190 0.029 2.74

50 0.090 0.085 7.61 0.890 0.103 50.27 0.090 0.122 59.98 0.100 0.140 13.34


Griff. 19

Site Description: MIA, Griffith tile drainage (TD) from horticultural area. Sampling pointscoincide with farm sump pumpouts used by NSW DLWC in their 10 year salinity check programme.Date: 30 August, 1994Sampling: 50 ml sample in glass syringe taken at each farm per collection.

Samples collected using a stainless steel bucket at pump out point.One litre samples also collected in amber bottle for GC analysis.

Tested for: Diuron, BromacilLimit of Reporting: Diuron: 0.2 µg/L (HPLC +); 0.05 µg/L (GC/MS*); 0.02 µg/L (ELISA#)

Bromacil: 0.2 µg/L (HPLC); 0.50 µg/L (GC/MS)* Diuron and linuron breakdown under GC/MS conditions to same compound used for quantification.# Diuron ELISA cross reacts with other urea herbicides (e.g linuron). + Presence/absence of linuron confirmed by HPLC prior to analysis.

Analytical method: CSIRO Griffith SPE-HPLC, LLE-GC/MS; CSIRO Division of Plant Industry, ELISA

Concentration (µg/L)Sample Diuron BromacilNo. ELISA HPLC GC/MS HPLC GC/MSTD9 0.09 0 0.07 0.2 ----TD10 0.35 0.4 0.32 ---- ----TD11 0.45 0.6 0.65 ---- ----TD15 ---- ---- ---- ---- ----TD16 ---- ---- ---- ---- ----TD21 0.25 0.2 0.16 0.26 ----TD22 0.15 0.2 0.13 0.23 ----TD23 ---- ---- ---- ---- ----TD25 0.18 0.2 0.13 1.02 0.84TD28 ---- ---- ---- ---- ----TD30 0.14 ---- 0.1 0.8 ----TD36 0.66 0.6 0.54 2.3 2.5TD38 0.34 0.3 0.23 0.2 ----TD40 0.69 0.85 0.8 3.4 3.9TD41 0.19 0.2 0.19 2.2 2.6TD44 0.04 ---- 0.052 ---- ----TD45 ---- ---- ---- ---- ----TD46 1.1 0.86 0.96 1.4 1.5TD48 0.88 1.08 1.04 0.39 0.68TD49 0.17 ---- 0.2 2.08 2.2TD50 ---- ---- ---- ---- ----


Griff. 20

Site Description. MIA, Leeton, Merungle Hill tile drainage (TD) from horticultural area.Selected farm sump pumpouts. Snapshot only.

Date: 9 December, 1992Sampling: Sample Collected using a stainless steel bucket at pump out point.

One litre samples collected in amber bottle .Tested for: Diuron (Di), Bromacil (Bro)Limit of Reporting: O.2 µg/L. NOTE: Only positives (i.e. > LOR) reportedAnalytical method: CSIRO, Griffith SPE-HPLC

Farm Diuron Bromacil

No. µg/L µg/L

A ---- 1

B ---- ----

C ---- ----

D ---- ----

E 0.31 ----

F 0.6 2.7

G 0.37 6.2

H 1.32 3.5

---- = below limit of reporting (LOR)

Griff. 21

Site Description. MIA, CIA surface drains. Sampled in Conjunction with NSW DLWCsurface water quality survey.

Date: Generally 3-monthly from December 1991 to March 1993Sampling: One litre amber glass bottle phosphate buffered to pH6.8.Tested for: Diuron (Di), Bromacil (Bro), Atrazine (At), Molinate (Mol), Malathion (Mal),

Chlorpyrifos (Chp).Limit of Reporting: 0.05 µg/L for all but Bromacil at 0.5 µg/L

NOTE: Only positives (i.e. > LOR) reported.Analytical method: CSIRO,Griffith LLE-GC/MS

MIA Surface Drains December, 1991

Concentration (µg/L)Di Mol At Bro Mal Chp

YOT ---- ---- ---- ---- ---- ----YMS 0.6 7.7 ---- ---- ---- ----GMS 0.19 4 ---- ---- ---- ----MDJ 0.21 1.07 ---- ---- ---- ----WW1 0.17 1.4 ---- ---- ---- ----WD ---- 2.7 0.08 ---- ---- ----

CIA Surface Drains.


CMC ---- ---- ---- ---- ---- ----COD ---- 1.8 ---- ---- ---- ----

DC500 ---- 7.9 ---- ---- ---- ----DC800 ---- 1.3 ---- ---- ---- ----

MIA Surface Drains. March 1992


YOT ---- ---- ---- ---- ---- ----YMS 0.07 ---- ---- ---- ---- ----GMS ---- ---- ---- ---- ---- ----MDJ 0.2 ---- ---- ---- ---- ----WWO 0.06 ---- ---- ---- ---- ----WWS 0.1 ---- 0.06 ---- ---- ----

CIA Surface Drains.


CMC ---- ---- ---- ---- ---- ----COD ---- ---- ---- ---- ---- ----

DC500 ---- ---- ---- ---- ---- ----DC800 ---- ---- ---- ---- ---- ----


Griff. 21 cont.

MIA Surface Drains. May 1992


YOT ---- ---- ---- ---- ---- ----YMS 0.87 ---- ---- 0.86 ---- ----GMS 0.17 ---- ---- ---- ----MDJ 2.1 ---- ---- 1.6 ---- ----WWS 1.05 ---- ---- 0.9 ---- ----LAG ---- ---- ---- ---- ---- ----LMK 3.4 ---- ---- 1.5 ---- ----

CIA Surface Drains.


COD ---- ---- ---- ---- ---- ----DC500 ---- ---- ---- ---- ---- ----DC800 ---- ---- ---- ---- ---- ----CMC ---- ---- ---- ---- ---- ----

MIA Surface Drains. December 1992


YOT ---- ---- ---- ---- ---- ----YMS ---- 27 ---- ---- ---- ----GMS 0.07 13.5 ---- ---- ---- ----MDJ 0.06 13.5 ---- ---- ---- ----WWO 0.2 21 0.26 ---- ---- ----WWS 0.23 5.7 0.22 ---- ---- ----LMK 0.4 37.5 0.11 ---- ---- ----

CIA Surface Drains.


---- ---- ---- ---- ---- ----CMC ---- ---- ---- ---- ---- ----COD 0.05 18 0.37 ---- ---- ----

DC500 0.1 17 0.25 ---- ---- ----DC800 0.37 9 ---- ---- ----

MIA Surface Drains. March 1993


YOT ---- ---- ---- ---- ---- ----YMS ---- 0.07 ---- ---- ---- ----GMS ---- 0.07 ---- ---- ---- ----MDJ ---- ---- ---- ---- ---- ----WWS 0.1 ---- 0.8 ---- ---- ----WWO ---- ---- ---- ---- ---- ----LMC ---- 0.08 ---- ---- ---- ----

CIA Surface Drains.


CMC ---- ---- ---- ---- ---- ----COD ---- ---- ---- ---- ---- ----

DC500 ---- ---- ---- ---- ---- ----DC800 ---- 0.07 0.1 ---- ---- ----


Griff. 22

Site Description. MIA, surface drains. Little Mirrool Creek daily monitoring.Date: 4 October, 1994 to 30 November, 1994Sampling: 24 h composite sample taken with an automatic sampler.Tested for: See belowLimit of Reporting: See belowAnalytical method: CSIRO, Griffith LLE-GC/MS

Sample Date Concentration(µg/L)

QualitativeOnly

No. (Day) Diuron Molina Malath Chlorpy. Atraz. Metola. Endo 1 Endo 2 Endo-SO4 Thioben Simazi. Diazin.

4/10

1 5/10 0.7 1.4 --- --- --- --- --- --- --- --- --- ---

2 6/10 0.33 1.6 0.01 --- --- --- --- --- --- --- --- ---

3 7/10 0.5 1.5 0.03 --- --- --- --- --- --- --- --- ---

4 8/10 0.4 4.5 0.11 --- --- --- --- --- --- --- --- ---

5 9/10 0.47 3.1 0.48 --- --- --- --- --- --- --- --- ---

6 10/10 3.6 3.2 0.44 (0.005) --- --- --- --- --- --- + ve ---

7 11/10 3.4 5.8 0.16 --- --- --- --- --- --- --- + ve ---

8 12/10 2.5 5.5 0.14 (0.008) --- 0.14 --- --- 0.01 --- + ve ---

9 13/10 2.4 4.4 0.06 --- (0.02) --- --- --- --- --- + ve ---

10 14/10 1.4 4.1 0.06 (0.006) --- --- --- --- 0.01 --- + ve ---

11 15/10 1.3 6.1 0.1 --- --- --- --- --- 0.015 --- + ve ---

12 16/10 2.1 4.4 0.09 --- --- --- --- --- --- --- + ve ---

13 17/10 5.9 5.1 0.05 --- --- --- --- --- 0.018 --- + ve ---

14 18/10 7.5 6.6 0.11 --- --- --- --- --- 0.015 --- + ve ---

15 19/10 2.2 3.6 0.06 --- --- --- --- --- 0.01 --- + ve ---

16 20/10 2 6.6 0.37 --- --- --- --- --- 0.01 --- + ve ---

17 21/10 1.8 8.5 0.4 0.03 --- --- --- --- 0.01 1.6 + ve ---

18 22/10 1.7 13 0.52 0.02 (0.02) --- --- --- 0.01 0.4 + ve ---

19 23/10 1.3 11 0.14 0.03 0.5 0.6 --- --- 0.01 0.16 + ve ---

20 24/10 1.1 6 0.05 0.015 0.11 0.12 --- --- 0.02 0.13 + ve ---

21 25/10 1.1 10.5 0.1 0.02 (.025) 0.05 --- --- 0.02 0.14 + ve ---

22 26/10 1.5 10 0.12 0.04 --- --- --- --- 0.015 0.07 + ve ---

23 27/10 0.7 6.3 0.16 0.02 --- --- --- --- 0.01 0.07 + ve ---

24 28/10 1.3 6.9 0.1 0.01 --- --- --- --- 0.01 0.1 + ve ---

25 29/10 1 11.2 0.05 0.015 --- 0.27 --- --- 0.025 0.15 + ve ---

26 30/10 0.6 9.2 0.04 0.01 --- 0.07 --- --- 0.01 0.18 + ve ---

27 31/10 1.2 7.7 0.02 0.015 --- --- --- --- 0.015 0.18 + ve ---

28 1/11 0.7 7.1 0.015 0.015 --- --- --- --- 0.015 0.24 + ve ---

29 2/11 0.5 10.2 0.06 0.01 --- --- --- --- 0.01 0.09 + ve ---

30 3/11 1.25 11 0.23 0.025 --- --- --- --- 0.025 0.15 + ve ---

31 4/11 0.87 11 0.06 0.015 --- --- --- --- 0.015 0.22 + ve ---

32 5/11 0.45 13.6 0.035 0.015 --- --- --- --- 0.015 0.55 + ve ---

33 6/11 0.1 14.9 0.05 0.07 --- 1.1 --- --- 0.02 0.17 + ve ---

34 7/11 0.75 40 0.18 0.03 --- --- --- --- 0.015 0.4 + ve ---

35 8/11 0.37 39 0.11 0.05 --- --- --- --- 0.01 0.35 + ve ---

36 9/11 0.18 30 0.06 0.02 --- --- --- --- --- 0.35 + ve ---

37 10/11 0.3 39 0.2 0.07 --- 0.18 --- --- --- 0.32 + ve ---

38 11/11 0.17 37 0.025 0.05 --- --- --- --- 0.01 0.25 --- ---

39 12/11 0.25 23 0.02 0.025 --- --- --- --- 0.01 0.17 --- ---

40 13/11 0.3 17 0.035 0.025 --- --- --- --- 0.01 0.16 --- ---

41 14/11 0.65 16 0.035 0.01 --- --- 0.1 0.04 0.025 0.09 --- ---

42 15/11 1.3 14 0.03 0.02 --- --- --- --- 0.03 0.09 --- ---

43 16/11 1.7 24 --- 0.05 --- --- --- --- 0.035 0.1 + ve ---

44 17/11 0.6 34 --- 0.07 --- --- --- --- 0.03 0.1 + ve ---

45 18/11 0.76 17 --- 0.025 --- --- --- --- 0.02 0.13 + ve ---

46 19/11 0.76 11 --- 0.025 0.07 0.09 --- --- 0.02 0.15 + ve ---

47 20/11 0.45 15 --- 0.015 0.1 0.17 --- --- 0.015 0.15 + ve ---

48 21/11 0.5 15.2 --- --- 0.08 0.15 --- --- 0.018 0.17 + ve ---

49 22/11 0.45 9.2 --- --- 0.14 0.22 --- --- --- 0.18 + ve ---

50 23/11 0.55 14.8 0.02 0.01 0.15 0.19 --- --- 0.02 0.19 + ve ---

51 24/11 0.55 17.1 --- 0.01 0.06 0.06 --- --- 0.02 0.22 + ve ---

52 25/11 0.5 18.6 --- 0.025 0.055 --- --- --- 0.015 0.1 + ve ---

53 26/11 0.55 25 --- 0.035 --- --- --- --- 0.015 0.09 + ve ---

54 27/11 0.46 21 --- 0.015 --- --- --- --- 0.04 0.085 + ve ---

55 28/11 1 15 --- 0.01 --- --- --- --- 0.03 --- + ve ---

56 29/11 0.5 9.2 0.05 0.01 --- --- --- --- 0.02 0.14 + ve ---

57 30/11 0.41 5.1 --- --- --- --- --- --- 0.015 0.11 + ve ---

LOR (µg/L) 0.05 0.05 0.01 0.01 0.05 0.05 0.01 0.01 0.01 0.05 NA NA

---- = below limit of reporting (LOR); ( ) = concentration below LOR, value inparentheses is an estimate only: + ve = detected (quantification not possible asstandards not available at the time of sampling); NA = not applicableCompounds also monitored but never detected above LOR: terbufos, lambda cyhalothrin,methidathion, methomyl, propanil, cypermethrin, profenofos, trifluralin, bromacil,deltamethrin, fluazifop-methyl, monocrotofos

Griff. 23

Site Description. MIA, surface drains. Mirrool Creek at McNamara Road daily monitoring.Date: 4 October, 1994 to 30 November, 1994Sampling: 24 h composite sample taken with an automatic sampler.Tested for: See belowLimit of Reporting: See belowAnalytical method: CSIRO, Griffith LLE-GC/MS

Sample Date Pesticide Concentration(µg/L)

QualitativeOnly

No. (Day) Diuron Molinate

Malathion

Chlorpyrifos

Atrazine

Metolachlor

Endo 1 Endo 2 Endo-SO4

Thiobencarb

Simazine

Diazinon

4/10

1 5/10 0.8 0.5 ---- ---- 0.28 0.32 ---- ---- ---- ---- + ve ----

2 6/10 0.29 0.38 ---- ---- 0.23 0.3 ---- ---- ---- ---- + ve ----

3 7/10 0.73 0.3 ---- ---- 0.29 0.37 ---- ---- ---- ---- + ve ----

4 8/10 0.58 0.33 0.025 ---- 0.22 0.33 ---- ---- ---- ---- + ve ----

5 9/10 0.5 0.28 0.03 ---- 0.74 1 ---- ---- ---- ---- + ve ----

6 10/10 0.55 0.3 0.03 ---- 0.3 0.38 ---- ---- ---- ---- ---- ----

7 11/10 0.71 0.31 0.08 ---- 0.18 0.21 ---- ---- ---- ---- ---- ----

8 12/10 0.5 0.5 0.03 ---- 0.15 ---- ---- ---- 0.01 ---- + ve ----

9 13/10 0.65 0.45 0.03 ---- 0.12 0.1 ---- ---- 0.01 ---- + ve ----

10 14/10 0.8 0.4 0.09 ---- 0.08 0.08 ---- ---- 0.01 ---- + ve ----

11 15/10 0.42 0.28 0.16 0.01 0.05 0.05 ---- ---- ---- ---- + ve ----

12 16/10 0.51 0.3 0.03 0.03 0.07 0.08 ---- ---- 0.015 ---- + ve ----

13 17/10 0.46 1.1 0.05 0.016 0.08 0.09 ---- ---- 0.012 ---- ---- ----

14 18/10 0.31 21.5 0.52 0.036 0.25 0.22 ---- ---- 0.01 ---- + ve ----

15 19/10 0.9 2.9 0.25 0.01 0.23 0.13 ---- ---- 0.01 ---- + ve ----

16 20/10 0.8 1.2 0.07 ---- 0.2 0.1 ---- ---- 0.01 ---- + ve ----

17 21/10 0.4 0.6 0.16 0.01 0.14 0.09 ---- ---- 0.02 ---- + ve ----

18 22/10 0.75 1.9 0.38 0.015 0.9 1.5 ---- ---- 0.015 2.7 + ve ----

19 23/10 0.35 3.7 0.05 0.015 0.15 0.2 ---- ---- 0.01 0.22 + ve ----

20 24/10 0.65 3.2 0.04 0.01 0.1 0.09 ---- ---- 0.015 0.11 + ve ----

21 25/10 0.75 3.4 0.04 0.01 0.15 0.11 ---- ---- 0.015 0.14 + ve ----

22 26/10 0.3 2.9 0.03 0.015 0.18 0.1 ---- ---- 0.015 0.05 + ve ----

23 27/10 0.35 2.3 0.065 0.01 0.17 0.1 ---- ---- 0.03 0.09 + ve ----

24 28/10 0.55 2.7 0.14 0.01 0.47 0.3 ---- ---- 0.04 0.3 + ve + ve

25 29/10 0.75 3 0.15 0.02 0.4 0.25 ---- ---- 0.025 0.25 + ve + ve

26 30/10 0.45 3 0.06 0.01 0.15 0.1 ---- ---- 0.025 0.09 + ve + ve

27 31/10 0.4 3.3 0.035 0.01 0.08 0.07 ---- ---- 0.015 0.23 + ve + ve

28 1/11 0.3 2.4 0.045 0.01 0.1 0.07 ---- ---- 0.015 0.09 + ve + ve

29 2/11 0.25 2.5 0.03 0.01 0.09 0.06 ---- ---- 0.015 0.09 + ve ----

30 3/11 0.31 2.8 0.04 0.01 0.19 0.17 ---- ---- 0.015 0.12 + ve ----

31 4/11 0.25 4.9 0.04 0.01 0.14 0.1 ---- ---- 0.015 0.13 + ve + ve

32 5/11 0.34 6.1 0.07 0.03 0.27 0.4 ---- ---- 0.015 0.25 + ve + ve

33 6/11 0.29 6 0.05 0.02 0.7 1.1 ---- ---- 0.015 1.7 + ve + ve

34 7/11 0.2 15.8 0.06 0.02 0.25 0.25 ---- ---- 0.05 4 + ve ----

35 8/11 0.26 19.8 0.28 0.05 0.2 0.19 ---- ---- 0.01 1.3 + ve ----

36 9/11 0.2 17 0.07 0.01 0.36 ---- ---- ---- 0.06 0.8 + ve ----

37 10/11 0.16 11 0.08 0.01 0.22 ---- ---- ---- ---- 0.46 + ve ----

38 11/11 0.6 11 0.035 0.015 0.2 0.13 ---- ---- 0.02 0.28 ---- ----

39 12/11 0.25 12 0.015 0.015 0.15 0.1 ---- ---- 0.03 0.8 ---- ----

40 13/11 0.25 13 0.01 0.05 0.15 0.08 ---- ---- 0.02 0.36 ---- ----

41 14/11 0.2 11 ---- 0.025 0.08 0.05 ---- ---- ---- 0.16 ---- ----

42 15/11 0.35 6.5 ---- 0.025 0.07 ---- ---- ---- 0.02 0.12 ---- ----

43 16/11 0.3 7.6 ---- 0.03 ---- 0.07 ---- ---- 0.035 0.15 + ve ----

44 17/11 0.5 7 ---- 0.015 0.07 0.09 ---- ---- 0.035 0.1 + ve ----

45 18/11 0.4 6 ---- 0.025 0.07 0.06 ---- ---- 0.03 0.1 + ve ----

46 19/11 0.35 5 ---- 0.075 0.1 0.08 ---- ---- 0.015 0.1 + ve ----

47 20/11 0.22 4 ---- 0.02 0.18 0.07 ---- ---- 0.02 0.08 + ve ----

48 21/11 0.3 8.2 ---- 0.015 0.16 0.1 ---- ---- 0.015 0.29 + ve ----

49 22/11 0.18 4.5 ---- 0.01 0.11 0.11 ---- ---- 0.015 0.18 + ve ----

50 23/11 0.14 2.5 ---- 0.015 0.12 0.1 ---- ---- 0.02 0.17 + ve ----

51 24/11 0.16 2.5 ---- ---- 0.09 0.08 ---- ---- 0.02 0.17 + ve ----

52 25/11 0.18 2.3 ---- ---- 0.2 0.08 ---- ---- 0.015 0.1 + ve ----

53 26/11 0.12 3 ---- ---- 0.18 0.07 ---- ---- ---- 0.09 + ve ----

54 27/11 0.1 4.8 ---- ---- 0.24 0.08 ---- ---- 0.02 0.095 + ve ----

55 28/11 0.5 4 ---- ---- 0.12 0.12 ---- ---- 0.02 0.12 + ve ----

56 29/11 0.28 2.7 ---- ---- 0.2 0.38 ---- ---- 0.015 0.12 + ve ----

57 30/11 0.17 1.9 ---- ---- 0.09 0.1 ---- ---- 0.02 0.06 + ve ----

LOR (µg/L) 0.05 0.05 0.01 0.01 0.05 0.05 0.01 0.01 0.01 0.05 NA NA

NOTE: ---- = below limit of reporting (LOR); NA = not applicable + ve = detected (quantification not possible as standards not available at the time ofsampling)

Compounds also monitored but never detected above LOR:terbufos, lambda cyhalothrin,methidathion, methomyl, propanil, cypermethrin, profenofos, trifluralin, bromacil,deltamethrin, fluazifop-methyl, monocrotofos

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PESTICIDE MONITORING IN THE IRRIGATION AREAS OF SOUTH