Coastal bathing water quality: the application of water quality standards to Welsh beaches

Applied Geography (1988), 8, 117-131

Coastal bathing water quality: the application of water quality standards to Welsh beaches

David Kay

Department of Geography, St David’s University College, University of Wales, Lampeter, Dyfed, SA48 7ED, UK

Abstract

European recreational water quality standards are based largely upon the enumeration of enteric indicator bacteria in the nearshore zone. The sampling strategies specified in current standards are not designed to provide management information which can be used to formulate strategies for the control of risk to the recreator population. Furthermore, the chosen parameter of water quality, namely the Escherichiu coli concentration, is increasingly questioned as a suitable enteric indicator species.

Recently, Britain has demonstrated an increased willingness to implement the spirit as well as the letter of the EEC 1976/160 Bathing Waters Directive. Water authorities and environmental health officers will be faced with the task of interpreting the datagenerated by the existing beach water quality monitoring programmes. They will increasingly be asked questions regarding the epidemiological safety of bathing water by the general public and resort towns. Such questions cannot be answered properly with present levels of data.

Present European and North American standards are applied to Welsh coastal bathing sites with the aim of demonstrating both the differential quality standards applied and the relative management utility of these two approaches.

Introduction

Britain discharges the waste from approximately six million people directly into the nearshore zone. In the summer bathing season this pollution load may double, providing a daily flow of some 2.148 x lo9 1 of sewage effluent. The Water Research Centre (1985) has estimated that some 191 recreational beaches are affected by outfalls serving populations in excess of 2000 people. The majority of these outfalls deliver raw untreated sewage into the bathing zone. Indeed, a Department of the Environment (DOE) report published in 1973 suggested that the majority of British outfalls do not even reach the low water mark. These conditions provide scope for beach fouling with faecal material and other solid wastes. This is both aesthetically unsatisfactory as well as providing a potential health risk (Wheeler 1986).

In addition, Ayrton and Oldridge (1987) have stated that clean recreational waters are of primary importance to the continued economic growth of Britain’s coastal resorts. They reported over 66 million tourist nights at the 17 top resort towns in the United Kingdom for the 1985 season. At Scarborough, which accounted for four million tourist nights, some 59 per cent of the town’s 32600 jobs were dependent upon the tourist industry. Increasingly, resort towns perceive the quality of their coastal bathing water as an important element in their marketing strategy. This was stressed in evidence presented to the 1985 House of Commons Welsh Affairs

0143-6228/88/02 0117-18 $03.00 0 1988 Butterworth & Co (Publishers) Ltd

118 Coastal bathing water quality on Welsh beaches

Committee investigations into coastal sewage pollution in Wales, when it was stated that:

Those authorities that have designated EEC beaches are now promoting them. They are using them as part of their tourist promotion. This places Wales in a position of dis- advantage. The extent to which it influences the public is not certain but as time goes on I suspect the public will become more and more aware of pollution problems and will be likely to give greater and greater credence to those authorities who advertise that they have ‘Eurobeaches’.

(House of Commons Committee on Welsh Affairs 1985b:154)

The public health risk from sewage-contaminated bathing waters is difficult to quantify. British authorities have always suggested that there is no risk of contracting serious illness unless the waters are so fouled as to be aesthetically revolting (Public Health Laboratory Service 1959; Medical Research Council 1959; Welsh Office 1985; Water Research Centre 1985; Welsh Water Authority 1985). This view is based upon a retrospective examination of serious or ‘notifiable’ illnesses which could be attributed to bathing in sewage-polluted sea waters in the period 1953 to 1958. In North America, prospective epidemiological studies have established a statistically significant link between water quality and patterns of bather morbidity. These epidemiological studies have formed the basis of water quality standards designed to prevent disease transmission which are widely applied throughout North America (Cabelli et al. 1975, 1976, 1982, 1983; Dufour 1982, 1983, 1984; Canadian Govern- ment 1983). There have been several recent calls for a replication of the North American prospective epidemiological studies in the United Kingdom in order to provide a firm scientific base for the definition of recreational water quality standards for British coastal waters (Stanfield 1982; ADC 1985; Evison 1985; Kay and McDonald 1986a).

The 1976 EC Bathing Waters Directive 76/160 provided one set of criteria which could be applied to United Kingdom recreational waters (European Community 1976). The British government’s reaction to this legislation was certainly ambivalent (Garnett 1981). Under the terms of the directive the national governments were required to designate ‘bathing areas’ which were defined as:

-a place where bathing is explicitly authorised or -a place where bathing is not prohibited or is traditionally practiced by large numbers

of people.

‘Bathing water’ was defined as:

-all running or still fresh water, or parts thereof and seawater.

Only 27 marine bathing sites were designated. This compares with the much higher numbers of recreation sites designated by other member states and defined in Table 1. In the cases of Denmark, France and Italy the numbers refer to sampling locations rather than beaches and Greece has designated a length of coastline. Data from these nations is not, therefore, directly comparable with the UK data.

In recent years the British government’s rejection of the best available epidemiological evidence and its restricted designation of coastal bathing sites has come under increasing attention (Royal Commission on Environmental Pollution 1984; Coastal Anti-Pollution League 1985; Consumer’s Association 1986; Kay and McDonald 1986b). This has generated political pressure to improve water quality at the nation’s coastal recreation sites which culminated in the report of the House of Commons Welsh Affairs Committee investigation into coastal sewage pollution in Wales (1985~). This document advocates the application of the EC directive standards to

David Kay 119

Table 1. Numbers of bathing waters designated by each member state under the terms

of the bathing waters Directive

Member state

Luxembourg Belgium Netherlands F.R. Germany Ireland Denmark France Italy United Kingdom Greece

Inland Coastal bathing bathing waters waters

39 0 41 15

323 60 85 9

0 6 139 1117

1362 1498 57 3308

0 27 2750 km total

Source: Water Research Centre (1985) and Institute for European Environmental Policy (1986)

many more bathing sites around the Welsh coast. The government reacted to this pressure by instigating a major sampling pro-

gramme of coastal bathing sites in December 1985 involving some 350 locations (Department of the Environment 1985a,b). This was followed in February 1987 with an announcement that the government would include 362 more bathing waters within the scope of the 1976/160 directive (Ayrton and Oldridge 1987). It is timely, therefore, to examine the application of the standards set out in the 19761160 directive and to define the likely utility that these standards will have for management of designated coastal recreation sites. In view of the central role played by Welsh parlia- mentarians and councillors in effecting this change in government policy, the application of the EC standards to Welsh recreation sites will form the case study of this contribution.

Water quality standards

Any water quality standard has two components. The parameters of measurement and the specified sampling regime.

Water quality parameters

The standards defined in directive 1976/160 cover physio-chemical and aesthetic aspects of a bathing water as well as the more often quoted enteric indicator species. Throughout Europe and North America the most common parameter used to indicate the safety of a bathing water is the coliform group of bacteria. These are useful indicators, which suggest that faecal contamination has taken place. This contamination may have been contributed by a pathogen carrier and, as such, it could constitute a risk to public health. It is this link between the coliform indicator and the risk of enteric pathogen presence that forms the scientific basis for the use of coliforms in defining the safety of bathing waters, drinking waters and foodstuffs. Coliform enumerations are routinely carried out by the water industry to determine


the safety of their potable and bathing waters. The coliform concentration has therefore become the accepted measure of recreational water quality within the water industry (Welsh Water Authority 1985).

Recent studies have called into question the utility of the coliform group as an indicator of risk in the coastal environment for two reasons. First, it has been shown that enterococci (faecal streptococci) concentrations demonstrate a higher correlation with rates of disease incidence amongst bathers than the more commonly used coliform enumerations. Cabelli er al. (1982) reported a correlation of + 0.96 between enterococci concentration and gastro-intestinal symptom rates but only + 0.58 between E. coli concentrations and symptom rates in New York bathers for the period 1973 to 1975.

The second reason why the coliform index should be questioned derives from the characteristics required of a good enteric indicator species. Mallard (1982:24) has defined these characteristics as follows:

1. 2. 3. 4. 5. 6. 7. 8.

9. 10.

Applicable to all types of water Present in sewage and polluted waters when pathogens are present Number is correlated with the amount of pollution Present in greater numbers than pathogens No aftergrowth in water Greater survival than pathogens Absent from unpolluted waters Easily detected by simple laboratory tests in the shortest possible time consistent with accurate results Has consistent characteristics Harmless to man and animals

Characteristics 2, 4, 5 and 6 are central in the estimate of risk at recreation sites. It is in these areas that the use of E. coli as a recreational water quality standard is increasingly questioned.

The relationship between viral pathogens and enteric indicator bacteria are a cause for particular concern. An infected person may excrete one million viral particles per gram of faeces. Enteric viruses account for the majority of cases of children admitted to hospital with acute diarrhoeal disease (Tyler 1985). Studies by Goyal and Adams (1984), at ocean sludge disposal sites, have demonstrated the survival of viruses in sediments for up to 17 months following the cessation of sewage sludge dumping. Viruses are known to survive in sea waters better than associated coliforms and Tyler (1985) reports no correlation between viral and indicator bacterial concentrations in 1074 samples collected from Welsh coastal waters. This lack of association is particu- larly serious because of the very low infective dose (one or two units) required to initiate a viral infection (Melnick and Gerba 1980).

The coliform group, as enumerated by the standard plating techniques used in regular water analysis (Department of Health and Social Security 1983), may not even be a good indicator of bacterial pollution. The plating methods of enumeration merely count bacterial cells which are capable of growth on a given medium. The absence of such growth does not prove that viable pathogens, or indeed indicators, do not exist in the environment. These viable but non-culturable cells can recover full virulence on introduction to an appropriate environment within an animal host (Colwell 1987). These findings are of considerable significance because current standards are based upon measurement of culturable not viable indicator bacteria. Where viable cells of pathogenic bacteria are stored in sediment for months or even years then Colwell (1987: 13) suggests that

David Kay 121

the question of public health safety associated with discharge of enteric pathogens to sea water. . . requires rethinking of ocean disposal, at the minimum, of the quantitative and qualitative aspects of waste disposal at sea.

It is clear from this discussion that the coliform indicator system is increasingly dubious for the determination of water quality at coastal recreation sites.

Sampling regime

The objective of the specified sampling regime is to define characteristic water quality information of use in both outfall design and recreation management. Ideally the data should enable a level of risk to be defined for a particular bathing water, although the extent to which this will be possible will depend on the validity of the indicator system employed as explained above. The information generated by the programme should be sufficiently robust to allow the adoption of politically sensitive management decisions which could involve beach closure (McDonald and Kay 1984; Baker 1985a,b).

Very few available sampling regimes fulfil the requirements set out above. The 19761160 directive defines ‘guide’ (recommended) and ‘imperative’ (mandatory) levels which should be complied with in 80 per cent and 95 per cent of cases respectively. The EC total coliform and E. co/i standards are set out in Table 2. Fortnightly sampling is suggested during the bathing season. In the temperate waters of Western Europe this might produce 10 samples during a full bathing season and this is insufficient to define a 95 per cent compliance rate. Furthermore, enteric bacterial concentrations generally show a log normal distribution with a few extreme values towards the upper range (Velz 1951). It is these episodes of high concentration and implied risk that demand management attention.

Compliance with the 95 per cent or 80 per cent directive criteria does not indicate the absence of risk. The EC sampling framework is seen therefore to fail on both criteria. It does not enable a risk level to be defined and it does not offer useful management information. Despite these drawbacks the directive standards are currently used as acceptable design criteria for new outfall schemes. Welsh Water have declared their intention to effect outfall improvements to bring recreational water quality within the limits set by the directive.

Table 2. EC Directive 7/160 bathing water quality standards for coliform bacteria

(fortnightly sampling)

Total coliform E. coli 1OOml-1 1OOml-1

Guide level 500 100 (recommended)

(80% of samples should not exceed this figure)

Imperative level (mandatory)

10000 2000

(95% of samples should not exceed this figure)

Source: European Community (1976)


Table 3. Sampling regimes and E. coli standards applied by various agencies

Agency Regime Faecal coliform

standard0

Toronto Health Department

Daily GM< 100 coliforms lGOml-I

(No sample to exceed 400 coliforms lGOml- I)

Canadian Federal 5-30 days GM<200 coliforms lOOmI- i

(Resample if any sample exceeds 400 coliforms

lOOmI-‘)

US Environmental Protection Agency

5-30 days GM< 200 coliforms lGOml-

(< 10% only to exceed 400 coliforms lOOmI-I)

’ GM = Geometric mean Source: Canadian Government (1983:25)

Alternative sampling regimes have been employed in North America. Table 3 outlines three North American sampling systems for recreational waters. Each of these requires more samples than the EC directive’s fortnightly regime. The maximum acceptable coliform concentration for each of these standards is also lower than the EC imperative level of 2000 100ml-l.

The reason for the higher water quality standards required in the United States and Canada is the widespread acceptance of the prospective epidemiological studies of Cabelli et al. (1982) and Dufour (1984) who have noted statistically significant health effects at beaches with indicator concentrations of 11 enterococci lOOml- I and 23 faecal coliforms lOOml- *.

Kay and McDonald (1985) have studied the bathing areas around Toronto on Lake Ontario. The sampling regime used here is one of daily sampling at 35 locations covering some 5 km of beaches. The lo-day running geometric mean is calculated and, where this value exceeds 100 faecal coliforms lOOml- I, the bathing area adjacent to the sampling point is closed to public access. If any single sample exceeds 400 faecal coliforms lOOml-I, the beach is immediately resampled with a view to appropriate management action.

The Toronto sampling regime involves more intensive sampling than the EC or US standards outlined in Tables 2 and 3. The objective in the Toronto case is to provide management information which can be used in protecting public health. In fact, even this high level of sampling effort does not provide satisfactory information because of the time lags required before an unsatisfactory water sample, indicating risk to the recreational user, can be weighed in the management decision process. The first of these lags is caused by the time required to analyse a sample for its coliform bacterial concentration. For a presumptive count of E. colt’ a minimum time of 18 hours is required, assuming the water is analysed immediately on collection (Depart- ment of Health and Social Security 1983). Hence, any real-time measurement of ‘risk’ is not possible using the coliform test. The second lag derives from the calcula- tion of the ten-day running mean value. Given the extreme variability of environmental bacterial concentrations, the brief episode of poor water quality might take a

David Kay 123

few days to increase the IO-day running geometric mean value to exceed 100 lOOml- *. At this point the beach manager might be ordering a beach to close during a period of fine weather with excellent water quality.

All potential sampling regimes are a compromise and the available parameters preclude continuous monitoring of recreational water quality. In general, the North American criteria are more stringent and require a greater intensity of sampling effort. This derives from the wider acceptance of more recent epidemiological investigations in North America and the requirement to provide ‘beach management’ information.

Welsh recreational waters

There are some 450 outfalls discharging to coastal waters in England and Wales. The Welsh coastal waters receive sewage from 112 of these. In addition, there are some 151 discharges to Welsh estuarine tidal waters, many of which are close to recreational beaches (Welsh Water Authority 1985). Table 4 shows the treatment given to sewage discharged from these outfalls.

It should be noted that the data in Table 4 are not weighted by either flow or population. Many of the outfalls receiving no treatment serve very low populations, whilst the multiple-treatment locations might have a very large throughput which is well treated. However, only eight existing schemes are defined by Welsh Water as modern offshore outfalls.

The maritime district councils, who have a public health responsibility and a concern for the tourist industry in their locality, clearly perceive this pattern of sewage disposal to be unsatisfactory. In 1984 they conducted a questionnaire survey of their members to determine the extent of the problem around the Welsh coast. Table 5 summarizes these questionnaire returns. Of the 22 returns, 19 district councils reported contaminated sea water, 16 reported contamination of the foreshore and 13 reported gross undisintegrated faecal material on the beaches or on the foreshore in their areas. The extent to which this constitutes an ‘aesthetically revolting’ situation (a condition which all competent authorities agree could lead to

Table 4. Treatment of sewage prior to outfall disposal in Wales

Treatment Numbers of outfalls receiving treatment0

1.

2.

3.

4.

5.

6.

7.

None

Secondary (i.e. biological treatment)

Maceration

Primary (i.e. sedimentation)

Tidal storage

Screening

Offshore sea outfall (i.e. a modern marine outfall)

100

64

37

34

31

17

8

’ At many outfalls multiple treatments are applied and there are thus 291 treatments listed here for 263 outfalls Source: Welsh Water Authority (1985:53-60)


Table 5. Selected summary of questionnaire returns presented by the committee of Welsh district councils to the Commons Welsh Affairs

Committee

Question

No. of positive reports by maritime district councils (max. 22)

1.

2.

3.

4.

5.

6.

Evidence of sewage pollution on or in the coastal area.

If ‘yes’ to question 1 is there (a) contamination of sea water

due to: (i) dumping of sewage sludge (ii) pollution from other DCs (iii) short sea outfalls (iv) other

(b) foreshore contamination due to: (i) short sea out falls (ii) other

Concern expressed by local general practitioner.

Evidence of gross undisintegrated faecal material on the beaches or within the coastal waters of the authority.

(i) regular evidence (ii) occasional evidence (iii) no evidence

Visible beach pollution from other sources (e.g. streams).

Extent to which outfalls comply with DOE criteria:

(i) extensive compliance (ii) some meet criteria (iii) none meet criteria (iv) no opinion

21

19

2 7

17 3

16

3 2

5

7 6 6

2

Source: ADC (1985)

disease transmission) is difficult to assess. However, the situation described in 1985 to the Commons Welsh Affairs Committee was considered unsatisfactory to the Maritime District Councils, the Coastal Anti-pollution League, and the Parlia- mentary Committee.

Standards and compliance

Given this ‘unsatisfactory’ situation one might expect a low level of compliance with existing water quality standards. Figures 1 and 2 show the distribution around the Welsh coast of 47 bathing areas which were ‘identified’ for water quality sampling by the DOE in 1985. This group contains all the 34 ‘high use’ beaches identified by Welsh Water in 1985 and several ‘moderate use’ locations.

Data describing water quality for these Welsh beaches were reported by the DOE in April 1987, together with information from a further 321 English beaches. Table 6

David Kay 125

Table 6. Summary of bathing water quality around the British coast in 1986

Authority Pass Fail Total

Northumbrian &‘A 9 10 19 Yorkshire WA 18 3 22 Anglian WA 20 8 28 Thames WA 1 1 2 Southern WA 41 24 65 Wessex WA (South coast) 24 3 27 South West WA 78 25 103 Wessex WA (Bristol Channel) 7 4 11 Welsh WA 23 24 47 North West WA 4 26 30 Northern Ireland Water Service 3 2 14

Totals 228 130 368

Nofe: No data are available from ten identified locations. Nine are in Northern Ireland and one is in the Yorkshire Water Authority area Source: DOE (1987)

provides a summary of these data, which indicate a 60 per cent compliance with EC imperative criteria for the identified beaches in England and Wales.

It is now the intention of the government (October 1987) that all the identified beaches should comply with the EC directive standards and that these locations should be formally ‘identified’ as bathing areas under the terms of the directive. Data from these 368 locations are to be sent to the European Commission in accordance with Article 13 of Directive 76/160. This reversal in government policy has resulted from both public pressure (White 1987) and threats of court action by the European Commission (Surveyor 1986).

The beach ‘identification’ criteria have not been fully specified. However, decisions on which of the 161 Welsh beaches should be identified for the 1986 sampling programme were based on the provision of facilities such as car parks and toilets available to recreational users (Pattinson 1987). Inevitably, these decisions are subjective and open to political pressure from the maritime local authorities, central government and the water industry.

The degree of compliance with the EC imperative level, as defined by the DOE, is presented in Table 7 and summarized in Table 8. This format of data presentation, which specifies either pass (P) or fail (F) for each beach is too simplistic because it implies a satisfactory state with no risk at the ‘pass’ beaches and a potential risk at the ‘fail’ beaches. In fact, both groups might experience high bacterial counts on isolated occasions which could indicate health risks to bathers. An additional problem is to delimit the 95 per cent or 80 per cent compliance rate with the low sample numbers available at many of the sampling locations. The DOE approach to this problem was to only allow beaches into the ‘pass’ category if they complied with both the E. coli and total coliform standards of the EC directive (see Table 2). Where there were less than 11 bacterial determinations for a bathing season no failures on either criteria were allowed for a ‘pass’ beach. A single determination failure was allowed where 12-39 samples were analysed for a bathing season. This is a fairly rigid application of the directive criteria and the fact that the DOE was forced to invent these arbitrary limits illustrates the internal inconsistency of this European legislation, which


Pass shown by black shading Fall shown by white shading Dot screen indicafes no data available 1 EEC ‘Gutie’leve( in 1985 2. EEC ‘Imperative level in 1985 3 Toronto standards (1985 data1 4. Canadian Federal siandards (1’985 data)

z --

0 Carmarthen

:;’ \ T-2

; ._ L._- _-- _-..r

:---

--_ .-

:- ---

_! .-

Figure 1. Compliance with both EC and North American standards at the 47 Welsh bathing locations in 1985.

requires a percentage compliance level impossible to calculate with the specified sampling interval. It is more realistic to allow one failure on a bathing beach with low sample numbers and generally low bacterial density. This is the approach taken in Table 7, where compliance with the EC directive and North American E. colt’ standard is specified in columns 6 to 20. The final column indicates the beach status as defined by the DOE criteria outlined above. Figures 1 and 2 show the extent to

David Kay 127

4. Canadian Federal siandards (1986 data) 5 U.S. Federal slmdards (1966 data)

3. Toton& standards (1966 data) I- -* _

Figure 2. Compliance with both EC and North American standards at the 47 Welsh bathing locations in 1986.

which the 47 ‘identified’ Welsh bathing beaches complied with these E. coli standards in 1985 and 1986 respectively.

The majority of these Welsh beaches pass the EC imperative standard but fail the EC guide level. For both 1985 and 1986 the EC guide level is seen to be more stringent than the North American federal standards, or indeed the more stringent Toronto criteria. Several beaches fail the North American federal standards, even though the


Table 7. Water quality during 1985 and 1986 at Welsh

Number of Passes and fails samples analysed EC directive

WWA sample 1985 1986 1985 1986 nninr Geom. r_..._

number used

Guide level

Imp. level

Guide Imp. mean level level 1985

Beach ll0.a Beach name

1 2 3 4

2

;I 9

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34

:: 37 38 39 40 41 42 43 44 45 46 47

Jacksons Bay 19055 Whitmore 19033 Cold Knapp 19037 Southerndown 19100 Trecco Bay 19114 Sandy Bay 19117 Rest Bay 19122 Aberavon 19051 Swansea Bay 39103 Bracelet Bay 39105 Limeslade Bay 39106 Langland Bay 30109 Caswell Bav Oxwich Bay

39111 39123

Port Eynon 39127 Rhossilli Beach 74010 Pembrey Beach 39005 Pendine Beach 39010 Amroth Beach 39013 Saundersfoot 39017 Tenbv North Tenby South

39020 39024

Broadhaven 39044 Newgale 39048 Whitesands 39051 Newuort Sands N New&ray

39065 39077

Abervstwvth S 39091 Aberystwyth N 39093 Borth 20023 Tywyn 20019 Fairbourne 20402 Barmouth 20014 Llandanwg 20028 Harlech 22596 Morfa Bvchan Cricietth’

22539 23142

Pwllheli 22589 Abersoch 22552 Llandudno W 25046 Llandudno N 25026 Colwyn Bay 25049 Kinmel Bay 3624 Rhyl 3608 Prestatvn Trearddur Bay

3614 27532

Benllech 27551

20 22 21 17

z 18 16 17 18 15 17 18 17 18 14 25 11 9 8

18 18 14 12 0

15 IO 10 10 9

: 9 8 9 0

10 10 10

; 13 12 8 8 9 9

19 3

20

:: 20 21 20 17 18 19 17 17 18 17 17 25 11 14 15 18 18 16 13 0

10 0

11 11 11 19 19 18 20 19 17 16 17 17 19 0

19 0

19 21 18 8

- F F F F F F F F F F F F F P P P F F F F F P F F ? F ? F P P F P F F F F F P P F ? F ? F F

:

F P F F F P P F P P P P P P P P P P P P P P F F 7

P 7

i P P F P P P

: P P P P ?

P ? F F F P

920 577 285 279

1373 1069 299 675 569 515 368 366 119 73 28 20 10 8

641 489

19 28 57 27

156 184 743 275

19

143 68

112

266 4

13 256 313 57s 660

1049 18

121 369

a As on Figs 1 and 2 b Data from two sample points (39044 and 84231). which together span the two study years c Technical failure of North American criteria on the percentage of samples over 4CO E. co/i 100mI-l. Pass has been

David Ka! 129

beaches identified as recreational bathing waters

Passes and fails Passes and fails 1985 1986

Passes and fails revised EC standard Passes and

Compliance fails EC

F F F F F F F F F F

: F I’ P P P P F F P P I’ I’ 7

F F F F P 1 ‘,

b F F 7

F P P F F F F F P F F

F F F F F F

F” F F F F F P P P P P F F P P P P ? F P F F P ? ? F F P ? F P P F F F F F P F F

Can. US Toronto fed. fed.

std std std

F F

: F

; F F F F F F P PC P PC PC

FF PC PE P P

5 P F F P ?

; F P ? F P PC F F

z F

: F

Geom. Can. mean Toronto fed. 1985 std std

1524 501 419 984 s12 755 678 337 668 457 709 306 242

73 30 35 22 59 22

187 68 38 86 28

234

186 4 4

26 9

129 88 42 91 66

2

2:;

371

907 129 27 99

F’ F F F F F F F F F F F P P P P P P F F

F’ P ? F ? F P P F P F F F F F P P F ? F ? F F F F

F F F F F F F F F F F F F P P P P P P F F P F P ? F ? F

:: F P F F F F F P P F ? F ? F F F F

US 1985 1986 with_WWA imperative fed. criteria level in DOE std (yes/no) survey 1956

F F F F F F F F F F F F F P PC P P PC

; F

I’ P ? F ? F P

z P F F F F F P PC F ? F ? F F F F

F F F F F F F F F F F F F P F P P P F P P P P P 3

F F F F P ? ? P P P ? F P

F’ P F F F P P F

F

L F F

; F F P F F P P P P P P P P F P F F ? P ? F P P F P P P P F P P F P 7

k ? F

F’ P

N N N Y N N Y N N Y Y Y Y Y Y Y Y Y Y Y N N Y Y ? Y Y N N ? N N N Y N Y N Y Y N N N N N Y Y N

F F F F F F F F F P F F P P P F P P F P P F F F P P P F P P F P P P P F P P P F P P F F F F P

declared where there are insufficient number of samples to complete a percentage figure and the geometric mean value is low ? = No data available


Table 8. Summary statistics for Welsh beaches in Table 7

Standard 1985 1986

EC guide level Pass 11 9 Fail 32 34

No data 4 4

EC imperative level Pass 24 30 Fail 19 13

No data 4 4

Toronto standards Pass 13 13 Fail 30 30

No data 4 4

Canadian federal standards Pass 15 13 Fail 28 30

No data 4 4 US federal standards Pass 15 13

Fail 28 30 No data 4 4

geometric mean E. co/i levels are within 200 lOOmI-I, because of the percentage of samples exceeding 400 E. coli lOOml- I. This applies to Caswell Bay (1985), Barmouth (1985) and Trearduur (1985). More surprising are those locations passing the Toronto geometric mean value of 100 coliforms lOOmI-l and still failing the North American standards because of the percentage of extreme values. Examples include Llandanwg (1985, 1986), Tenby North (1986), Broadhaven (1986), Harlech (1986), Morfa Bychan (1986) and Trearddur Bay (1986). Indeed, Trearddur (1986) fails both European and North American criteria with a geometric mean value of only 27 E. co/i lOOml- I. It is the few high values in the data and the nature of the statistical distributions of environmental bacterial concentrations that cause this failure pattern. In some cases beaches can fail the EC standards but pass the North American. For example, Oxwich Bay (1985) fails the guide level but passes all North American criteria. A similar pattern can be seen at the Tenby beaches (1985), at Newgate (1986) and Borth (1985).

There has been recent pressure to reconsider the EC imperative standard of 2000 E. coli lOOmI- t. The conclusions of the 1986 Montpellier seminar on the quality of bathing water suggested a level of 1000 E. co/i 100ml-l (Institute for European Environmental Policy 1986:8, 13). At this level only 18 and 21 Welsh beaches would pass using 1985 and 1986 data respectively (Table 7).

Management implications

The pattern of compliance summarized in Tables 6 and 7 can not be considered satisfactory. Indeed, Welsh Water are committed to an f80-million programme of improvements that will enable all 47 beaches to comply with the present EC imperative levels by the year 2000. If this standard was applied to all Welsh recreational waters the cost would be approximately f200 x 106. The equivalent figure for all ten regional water authorities in England and Wales is f 1000 x lo6 (White 1987). As the competent authority responsible for the maintenance of recreational water quality, Welsh Water can only be expected to work within the legislative framework currently in force. However, two questions should be addressed in the formulation of future

David Kay 131

expenditure plans. The first relates to the standards used in outfall design. If the present EC imperative level is the target for water quality improvement by new outfall schemes, then the authority may be required to implement expensive additional future engineering works to comply with more stringent EC standards. The second question relates to the management information required from the recreational waters sampling programme. There are clear inconsistencies in the sampling programme required by directive 76/ 160; in particular, the requirement to define a 95 per cent compliance figure from fortnightly samples.

There is increasing public awareness of bathing water quality. This awareness will lead to greater demands on the water industry for information and environmental control. Control may be restricted to acceptable sewage treatment and disposal strategies. However, control might also extend to the separation of bathers and sewage by beach closures or, at least, warning notices. Whilst there are no plans in Wales to implement such a policy, beach closures are practised by Britain’s European partners, who are applying the same EC legislation, and by many authorities in North America (McDonald and Kay 1984). However, the present sampling regimes in both North America and Europe do not provide the essential management information required to underpin any such policy of beach closure.

This case study illustrates the confusion of recent national government policy in this area of environmental management. Welsh Water has substantial beach water quality data derived from extensive surveys carried out since 1977. These data cover 161 bathing waters and include over 374 sampling locations. Summary data have been published in the appendices to the 1985 Commons Welsh Affairs Committee Minutes of Evidence and the authority has won praise from such environmental pressure groups as the Coastal Anti-pollution League for the open access allowed to its data records and its extensive monitoring effort. Indeed, in terms of the effort devoted to beach water sampling, the Welsh programme would rank Wales fifth in the list of EC nations presented in Table 1. Similar but less extensive programmes have been undertaken by the English coastal water authorities. Given this data base, it is surprising that the DOE ordered an additional sampling effort in 1985 in response to public concern over beach water quality. Additional data alone will answer none of the issues addressed in this paper and, in the Welsh context, the 1986 sampling programme did not produce new information. National effort should be devoted to the development of relevant faecal indicator systems for use in coastal recreational waters, and to the definition of epidemiological relationships between bathing in sewage-polluted sea waters and bather morbidity. If, as several government scientists have suggested, there is no such relationship or consequent risk, this could be proven by a well-designed epidemiological study and the high expenditures required for sewage outfal1 improvements could be directed to other uses.

At present, the EC directive 160176 has little credibility on epidemiological grounds and it may be considerably tightened in the future (Institute for European Environmental Policy 1986). It may be wise therefore for agencies to await the outcome of this debate before accepting the EC imperative level as the acceptable design criteria for new schemes.

Acknowledgements

The water quality data presented in this paper were supplied by Welsh Water. I am grateful to Dr C. Pattinson of the Welsh Water, Tidal Waters Unit at Bridgend for supplying the data and giving of his time to discuss the issues raised in this paper. Mr T. Harris designed and drafted the figures. Mrs W. Griffiths completed the data


input and St David’s University College Pantyfedwen fund provided financial support for this research. Dr A. T. McDonald provided valuable comments on a draft of the paper.

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(Revised manuscript received 23 October 1987)

Documents

Coastal bathing water quality: the application of water quality standards to Welsh beaches