Total Arsenic and Total Mercury Concentrations of The

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Jacquiline C. Lam and Glenn L. Sia Su, 2009. Total Arsenic and Total Mercury Concentrations of the Waters and

Janitor Fishes (Pterygoplichthys Spp.) in the Marikina River, Philippines.

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Journal of Applied Sciences in Environmental Sanitation, 4 (1): 37-42.

Research Paper

TOTAL ARSENIC AND TOTAL MERCURY CONCENTRATIONS OF THEWATERS AND JANITOR FISHES (PTERYGOPLICHTHYS SPP.) IN THE

MARIKINA RIVER, PHILIPPINES

JACQUILINE C. LAM and GLENN L. SIA SU*

Biology Department, De La Salle University, 2401 Taft Avenue, Manila, Philippines*Corresponding Author: Phone/fax: +63-2-536-0228. Email: [email protected]

Received: 9th January 2009; Revised: 8th February 2009; Accepted: 10th February 2009

Abstract: The study assessed the total arsenic and total mercury concentrations of thewaters obtained and janitor fishes (Pterygoplichthys spp.) caught from the upstreamand downstream areas of the Marikina River in June 2008. Results of the study showedthat the waters of the Marikina River had mean total arsenic and total mercuryconcentrations of 0.001 and 0.084 mg L-1, respectively, and the fishes examined hadmean total arsenic and total mercury concentrations of 0.015 and 0.012 mg kg-1,

respectively. There were no significant differences in the total arsenic and total mercuryconcentrations of both the upstream and downstream areas of the Marikina River, aswell as of the janitor fishes caught from both areas. Continuous water quality and biotamonitoring is encouraged to effectively analyze the impact of these heavy metals to theenvironment and human health.

Keywords: Arsenic, mercury, river basin, Janitor fish

INTRODUCTION

The Marikina River is an important river basin situated at eastern Metro Manila, Philippines.It intersects with the Pasig River and largely affects the tributaries of Laguna Lake. It has a totalarea of 75.2 ha and is 11 km long. In the past, it is known to be diverse, as a number of fishspecies live in its waters. But since the late 1990s, the Marikina River has been plagued by theinfestation of an invasive species, the janitor fish (Pterygoplichthys spp.). Despite this adversity, itcontinues to provide for those people who are continuously dependent on it for their livelihood.However, the Marikina River, like other rivers in the world, is also exposed to heavy metals, whichare emitted mostly from anthropogenic sources.

Two of the most toxic heavy metals, which are naturally occurring in the environment, arearsenic and mercury. Historically, arsenic and mercury are used extensively for the benefits [1]that they provide, but the continuous use of these metals brings about numerous environmental

and health implications that are of great concern, particularly to the general public exposed to

ISSN 0126-2807

Vo lume 4 , Number 1 : 37-42 , January -Apr i l , 2009 T2009 Department of Environmental Engineer ingS e p u l u h N o p e m b e r I n s t i t u t e o f T e c h n o l o g y , S u r a b a y a& Indonesian Society of Sanitary and Environmental Engineers, JakartaO p e n A c c e s s h t t p : / / w w w . t r i s a n i t a . o r g


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these toxic metals. Studies [2, 3] have shown that the concentration of these heavy metals in theenvironment, particularly in surface waters, is dependent on several factors, such as atmosphericdeposition of the metals, local point sources, and natural presence of the metals in bedrocks andsoils. The concern nowadays arises when these heavy metals persist in the environment in huge

amounts and create harmful effects. They enter and bioaccumulate in the food chains [4] and, inthe long run, persist in the environment [1] and induce harm to human health [5]. To date, therehad been few Philippine studies that dealt in determining the surface water quality and biota ofthe Marikina River for the heavy metals arsenic and mercury, but no study has explored anddetermined the concentrations of these heavy metals in the Marikina River. With these concerns,this study's main objective is to assess the extent of heavy metal pollution, particularly totalarsenic and total mercury concentrations, of the waters and the janitor fishes caught from theupstream and downstream areas of the Marikina River.

MATERIALS AND METHODS

The Marikina River is situated at the heart of Marikina City in Metro Manila. Marikina City iscomposed of 16 communities. Upstream and downstream sampling points stretching the entireMarikina River were randomly selected from a list of communities prepared by the authors.

Figure 1. Study site and the sampling points of the Marikina River

Three communities at the upstream and two communities at the downstream areas werechosen. The communities of Nangka, Tumana, and Malanday were identified to represent theupstream area of the Marikina River, whereas the communities of Santo Nio and Barangka wereidentified to represent the downstream area. The sampling points of the upstream area are

between the coordinates of 143855North, 1210555East, whereas the sampling points of the

downstream area are between the coordinates of 143756North and 1210533East. The


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water sampling and janitor fish collection were done in June 2008. Grab water samples werecollected at selected sampling points of the Marikina River. Janitor fishes (Pterygoplichthys spp.)were also caught from the designated sampling points of the river using a trawl net. Fishescaught were measured for their length. Fishes were dissected, wrapped in aluminum foil, and

returned to the laboratory where they were frozen. Water and fish samples collected wereassessed for total arsenic and total mercury concentrations following the procedures of AmericanSociety for Testing and Material, American Public Health Association, American Waterworks

Association, and Water Environment Federation [6, 7].The pH and the total dissolved solids (TDS) in the water were directly measured with a

pH/ISE meter (Orion 720A, Boston, USA) and a portable conductivity/TDS/salinity meter (Orion115A+, USA). Grab water samples were initially passed through a PALL GN-6 Metricel 0.45-mmembrane disc filter in a vacuum and were acidified for preservation using 1.5 mL ofconcentrated nitric acid (Merck, Germany) for every liter of water sample. The water sampleswere transferred in polyethylene bottles and stored in room temperature prior to metal analyses.

The total arsenic concentrations of the water and janitor fish samples were determined afterthe hydride vapor generation technique using an atomic absorption spectrophotometer(Shimadzu AA-6800F, Kyoto, Japan) with a hydride vapor generator (Shimadzu HVG-1, Kyoto,Japan) at a wavelength of 193.7 nm. The wet digestion method was used in the analysis of thefish samples for total arsenic before using the atomic absorption spectrophotometer-hydridevapor generator. Total mercury concentrations of the water and janitor fish samples weredetermined by the cold vapor technique using the mercury analyzer Hg254N (SeefelderMetechnik, Seefeld, Germany). Triplicate trials were performed for each water and fishdetermination. Quality control checks were run for both the atomic absorption spectrophotometer-hydride vapor generator and the mercury analyzer. Appropriate blanks, calibration standards,control and check standards, and duplicate and spiked samples for every 10 samples were

prepared for each of the variables tested.Results of the water and fish samples tested for total arsenic and total mercuryconcentrations from the upstream and downstream areas of the Marikina River were analyzedusing the t-test for unpaired observations. The t-test assumed that all the variables analyzed werenormally distributed at a 95% significance level. As the t-test requires the variances to be equal,Bartlett's test for homogeneity of variance was conducted to determine the equality of variances,whereas the Satterthwaite's test was done to adjust unequal variances. The null hypothesis forthe t-test indicated no significant differences in the total arsenic and total mercury concentrationsof the upstream and downstream areas of the Marikina River, whereas the alternate hypothesispresented significant differences of the total arsenic and total mercury concentrations in theupstream and downstream areas of Marikina River. The test indicating P < 0.05 could be a

reason to conclude that the differences between the upstream and downstream areas weresignificant. Data were analyzed using the Statistical Package for Social Sciences (SPSS)software.

RESULTS AND DISCUSSION

All pH levels of the waters in the Marikina River met the normal standard (pH 6.58.5) forfresh surface waters classified under the Department of Environment and Natural Resources(DENR) administrative order no. 34 series of 1990. The mean pH of the waters obtained was7.47. The mean TDS concentration in the Marikina River was 173 mg L -1 and within the normal


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standards (TDS < 1,000 mg L-1) under the DENR-Environmental Management Bureau (EMB)administrative order no. 34 series of 1990 [9].

The janitor fishes caught were in the range of 8 to 11 inches long. Arsenic and mercuryconcentrations were detected in the janitor fishes caught and in the waters obtained from the

upstream and downstream sampling points of the Marikina River. The mean standard deviationfor total arsenic and total mercury concentrations in the water were 0.001016 0.00016 and0.0932 0.04101 mg L-1, respectively. The mean standard deviation for total arsenic and totalmercury concentrations in the fish tissues were 0.0159 0.00276 and 0.0142 0.02104 mg kg -1,respectively. The obtained mean total arsenic concentrations of the waters of Marikina River wereway below the limit of 0.05 mg L-1 but the mean total mercury concentrations exceeded the limitof 0.002 mg L-1 under the DENR-EMB administrative order no. 34 series of 1990 [9]. Theobtained mean total arsenic and total mercury concentrations detected in the janitor fishes caughtfrom the Marikina River were, likewise, within the criteria for concentrations of total mercury in thefish at 1,000 g kg-1 [1], and the average concentration of arsenic in the fish in uncontaminatedwaters typically ranges from 10 to 400 mg kg-1 [8]. The results of the study suggest that there isno significant arsenic and mercury concentration detected in the janitor fishes that may pose adanger to the general public's health if consumed.

Tables 1 and 2 show all sampling points assessed in the upstream and downstream areas ofthe Marikina River in terms of the total arsenic and total mercury concentrations of the waters and

janitor fishes, respectively. No significant differences were observed in all the water obtained andthe janitor fishes caught from both upstream and downstream sampling points (P> 0.05) of theMarikina River.

Table 1: Mean concentrations of total arsenic and total mercury and t-test results of the watersobtained from upstream and downstream areas of the Marikina River in June 2008

Parameter Normal standard [9] Upstream areas(n = 3)

Downstream areas(n = 2)

t-test

Total As (mg L-1) 0.05 0.0010 0.0010 0.781a

Total Hg (mg L-1) 0.002 0.0763 0.1045 0.313a

aPvalue is not significant.

Table 2: Mean concentrations of total arsenic and total mercury and t test results in the janitorfishes caught from the upstream and downstream areas of the Marikina River in June2008

Parameter Normal standard Upstream areas

(n = 3)

Downstream areas

(n = 2)

t-test

Total As (mg kg-1) 10400 [8] 0.0145 0.0169 0.199a

Total Hg (mg kg-1) 1 [1] 0.0114 0.0161 0.748a

aPvalue is not significant.

This was a cross-sectional study, and its scope is limited in determining the total arsenic andtotal mercury concentrations of the waters taken at the upstream and downstream areas and the

janitor fishes caught from the Marikina River's upstream and downstream areas. The fish lengthswere not correlated with their accumulation of arsenic and mercury, as shown in a previous study[10]; it indicated that no significant relationship has been found between the heavy metalconcentrations in the muscle tissue and the fish lengths. Results of the study showed that arsenic


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and mercury concentrations in the janitor fishes were detected but these concentrations were allwithin the permissible limits. Arsenic and mercury concentrations were likewise detected in thewaters of Marikina River. Only the total arsenic concentrations of the waters were way below thepermissible limits, but the total mercury concentrations of the waters exceeded the permissible

limit of 0.002 mg L-1. It is likely that the total mercury concentrations in the waterways may becaused by the release of mercury from atmospheric deposition. A previous study [11] indicatedthat the contamination of the environment, particularly in inland waters, might be because of theanthropogenic atmospheric emissions of mercury.

We also show here that there have been no significant differences in the concentrations oftotal arsenic and total mercury of the waters obtained and janitor fishes caught from the upstreamand downstream areas of the Marikina River. It is likely that the total arsenic and total mercuryconcentrations of the waters and the fishes may be because of the discharges of thecontaminants in the river, and it is reasonable to assume that their detection is related to thedeposition of the atmospheric transported contaminants [11], sediment deposition, and increasedmobilization from soils and bedrocks [12]. The lack of significant differences between theupstream and downstream areas in the Marikina River may be because of their nearness to theroads and the constant exposure to emissions of the atmospheric transport contaminants.

CONCLUSION

This study assessed the total arsenic and total mercury concentrations of the watersobtained and the janitor fishes caught from the upstream and downstream areas of the MarikinaRiver. Results showed that arsenic and mercury concentrations in the waters and the fishes weredetected, and they were way below the permissible limits set by the DENR-EMB [9], except forthe total mercury concentration of the waters. The elevated concentration of mercury to the

permissible limit was most likely caused by anthropogenic atmospheric depositions. Communitiesrelying on the Marikina River, which are in constant exposure to arsenic and mercuryconcentrations deposited in the river by atmospheric transport emissions, may be at risk in thelong term. More in-depth studies and heavy metals monitoring of the waters and the biota of theMarikina River should be conducted in order to address the hazards and safeguard theenvironment and public health. Results of these researches would eventually guide decisions andenvironmental health policies on the protection of water sources and the lives of the people whoare very much dependent on these waterways.

Acknowledgement: We would like to express our sincerest gratitude to all who have assisted andsupported this study.

References1. Cooper, C. M. and W.B. Gillespie Jr., 2001. Arsenic and mercury concentrations in major landscape

components of an intensively cultivated watershed. Environmental Pollution, 1: 67-74.2. Skjelkvale, B. L., Andersen, T., Fjeld, E., Mannio, J., Wilander, A., Johansson, K., Jensen, J. P. and

T. Moiseenko, 2001. Heavy metal surveys in Nordic Lakes; concentrations, geographicpatterns and relation to critical limits. Ambio, 30(1): 2-10.

3. Jackson, T. A., 1997. Long-range atmospheric transport of mercury to ecosystems and theimportance of anthropogenic emissions a critical review and evaluation of the publishedevidence. Environment Reviews, 5: 99-120

4. Spry, D. J. and J.G. Wiener, 1991. Metal bioavailability and toxicity to fish in low-alkalinity lakes. Acritical review. Environmental Pollution, 71: 243-304.


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5. Erdogrul, O., 2007. Determination of mercury levels in edible tissues of various fish samples from SirDam Lake. Turkish Journal of Biology, 31: 197-201.

6. ASTM-American Society for Testing and Material, 2007. D2972-03 Standard test methods for arsenicin water. West Conshohocken, PA, USA.

7. APHA, AWWA, WEF-American Public Health Association, American Waterworks Association, andWater Environment Federation, 1998. Standard method for the examination of water andwastewater 20th edn. Washington DC, USA.

8. Lacayo, M. L., Cruz, A., Calero, S., Lacayo, J. and I. Fomsgaard, 1992. Total arsenic in water, fish,and sediments from Lake Xolotlan, Managua, Nicaragua. Bulletin of EnvironmentalContamination Toxicology, 49: 463-470.

9. DENR-EMB-Department of Environment and Natural Resources-Environmental ManagementBureau, 1990. DENR administrative order no. 34 (DAO 34) series of 1990. Subject: Revisedwater usage and classification water quality criteria. DENR, Quezon City, Philippines.

10. Storelli, M. M. and G.O. Marcotrigiano, 2004. Interspecific variation in total arsenic bodyconcentrations in elasmobranch fish from the Mediterranean Sea. Marine Pollution Bulletin 48:1145-1167.

11. Sing, K. A., Hryhorczuk, V., Saffirio, G., Sinks, T., Paschal, D. C., Sorensen, J.and E. H. Chen, 2003.Organic mercury levels among the Yanomama of the Brazilian Amazon basin. Ambio, 32(7):434-439.

12. Rognerud, S. and E. Fjeld, 2001. Trace element contamination of Norwegian lake sediments. Ambio,30(1): 11-19.

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