Pertanika 10(2), 175-181 (1987)

Distribution of Mercury in the Kelang Estuary

A.T. LAW and A. SINGH1

Department of Fishing Technology and Marine Science,Faculty of Fisheries and Marine Science,

Universiti Pertanian Malaysia,43400 Serdang, Selangor, Malaysia.

Key words: Mercury; pollution; estuary; Malaysia.

ABSTRAK

Taburan jumlah raksa dalam air dan enapan muara Kelang telah dikaji. Kepekatan minjumlah raksa dalam air adalah L 69\lg/1 dengan julat di antara 0.10 dan 6.50jJLg/l Untuk kandunganraksa dalam enapan, minnya adalah 0.20mg/kg enapan basah dengan julat di antara 0.03 danOAOmg/kg enapan basah. Kepekatan jumlah raksa dalam air muara ini adalah lebih tinggi daripadanilai yang dilaporkan untuk Selat Melaka dan juga Laut China Selatan. Kandungan raksa dalamenapan adalah setanding dengan sesetengah enapan muara di British dan agak tinggi daripadaenapan persisiran Mediterranean Turki. Keputusan ini menunjukkan bahawa muara Kelang telahmengalami pencemaran raksa pada peringkat rendah.

ABSTRACT

The distribution of total mercury in the water and sediment of Kelang estuary was studied. Themean level in water was 1.69/ig/lwith a range of 0.10 to 6.50/ug/l, while in the sediment, the mean was0.20mg/kg wet sediment with a 0.03 to 0.40mg/kg wet sediment range. The total mercury level in theKelang estuarine waters was much higher than that detected in the Straits of Malacca and SouthChina Sea. The mercury content in the sediment was comparable to some of the British estuarinesediment and was much higher that reported for the Turkish Mediterranean coastal sediments. Theresults suggest that the Kelang estuary carries some degree of mercury pollution.

INTRODUCTIONThe Minamatta disease outbreak in the early1950s, resulting from the consumption of alkylmercury contaminated fish and shellfish inJapan, alerted the world to the acute problemposed by mercury pollution. Many studies havebeen conducted on the distribution andbehaviour of mercury in the estuarine andcoastal waters (Tuncel et al, 1980; Airey andJones, 1982; Takeda et al, 1984; Campbell etal.f 1986), in marine organisms (Greig andWenzloff, 1977; Chia and Tong, 1981; Babji etal, 1983;Jothye*a/., 1983; Kiorb^e et al, 1983;Liong, 1983; Medina et al, 1986), and in

marine sediment (Barlett et al, 1978; Langston,1982; Sakamoto, 1985).

Studies on mercury distribution in theMalaysian aquatic environment is limited. Chanet al (1978) studied the distribution of mercuryin the Kelang River, while Chia and Tong (1981)investigated the mercury content in fishes caughtin the Kelang river mouth. Sivalingam andAhzura (1980) reported the mercury content inorgans of finfish and shellfish caught in Penang.Since no information of the mercury distributionin the Kelang estuary is available, this study wasundertaken to assess the mercury levels in thewater and sediment of this estuary.

1 Present address: Chem-solv Technologies Sdn. Bhd., 63B, Jalan Negara, Taman Melawati, 53100 Kuala Lumpur.

A.T. LAW AND SINGH

MATERIALS AND METHODS

Study AreaSix sampling stations were selected for this study;Stations CB, KB, I, II, III and IV. The locationsof the sampling stations were the same asdescribed previously (Law and Singh, 1986).The stations were visited eight times betweenApril 1981 and February 1982.

Sample Collection and PreservationSampling techniques for water and sedimentfollowed the methods adopted by Law and Singh(1986).

Water. Immediately after a sample wastaken, 100ml of it was transferred into a 300mlBOD bottle (Wheaton) containing 5ml of con-centrated HNO3and 0.05g K2Cr2O?. Triplicatesamples were collected and they were kept coolin an ice box. The samples were brought back tothe laboratory and kept at — 20°C until analysis.

Sediment. The sediment samples weretaken from the centre of the Ekman grab with anacid cleaned polyethylene spoon. The sampleswere placed in a plastic bag and cooled in an icebox. They were brought back to the laboratoryand kept at - 20°C until analysis.

Mercury AnalysisWater. In the laboratory, 5ml of concentratedH2SO4and 15ml 6% (w/v) KMnO4were addedto the preserved water sample while the samplewas kept cool under running tap water. Thetreated water sample was kept at room tempe-rature for 15 minutes, then 10ml of 5% (w/v)KgS2Ogwas added and it was heated in a waterbath at 95°C for 2 hours. Excess permanganatewas reduced with 5 % (w/v) hydroxylaminechloride which was added drop by drop to thesample. The mercury content in the treatedsample was determined by the cold vapourflameless atomic absorption technique (BITC,1979). An IL 251 atomic absorption spectrophotometer with background correction wasused for the analysis. The Titrisol Ampoule(Merck) Standard Solution was used for calibra-tion. The sensitivity of this method was 3ngmercury. A standard deviation of ±0.04|ig/lwas detected at 1 .OO|ULg/l mercury level.

Sediment. Determination of the mercurycontent in the sediment followed the method ofIskandar et al. (1972). About two grams ofsediment was weighed and placed into a 300mlBOD bottle. Fifteen millilitre of sulfuric acid:nitric acid mixture (2:1) was added to thesample. The mixture was digested in a shakingwater bath at 60°C for 2 hours. After digestion,10ml of 6% (w/v) potassium permanganatesolution was added and the sample was left forfurther digestion at room temperature over-night. Excess permanganate was reduced with5 % hydroxylamine chloride. The digestedsample was adjusted to 100ml with 6N HC1 andits mercury content was determined by the coldvapour flameless method. Mercury recovery wasreproducible at 97%. A standard deviation of± 0.04/zg at 1 -OOjuig mercury level.

RESULTSThe total mercury depth profiles of the samplingstations are shown in Table 1, while the dissolvedoxygen and pH profiles are given in Table 2.The total mercury contents in the sediment arepresented in Table 3.

The mean total mercury level in water atStations CB, KB, I, II, III and IV were 0.79fig/l,l.OS/ig/1, 2.15ng/l, 1.06ug/l and 1.96*ig/l res-pectively. In the sediments, the mean levels were0.45, 0.43, 0.35, 0.22, 0.17 and 0.21mg/kg wetsediment respectively.

The hourly monitoring of mercury in thesurface waters at Station KB taken on 25.2.82and 28.2.82 is shown in Figure L The resultsindicate that a higher level of mercury wasdetected in the water between noon and 7 pmwith 8.5 to 8.&/zg/l. However, in the morning orafter 7 pm, the level dropped below 2|ig/l.

DISCUSSIONThe data revealed that similar levels of totalmercury ranging from 0.79Mg/l to 2.15fJtg/lwere detected in the waters of all the samplingstations. This is in contrast to the distribution ofmanganese, iron, lead, copper and zinc in thesame estuary where concentrations were substan-tially diluted in the estuarine waters (Law andSingh, 1986). From the salinity data of Law andSingh (1986), Stations CB and KB may be con-sidered to be situated in the freshwater zone of

176 PERTANIKA VOL. 10 NO. 2, 1987

TABLE 1Distribution of total mercury in Kelang estuary (in jUg/1)

0>»̂w^ •

oZOM

to2S

Sampling dateStation

CB

KB

I

II

III

IV

Not determined*Mean ± S.D.' Sampling time,4 Average of two

Depth(m)0.5

0.5

0.55.07.0

10.015.0

0.55.07.0

10.015.0

0.55.07.0

10.015.0

0.55.07.0

10.015.0

I.

hour.samples.

29.4.81

l

1.104

1.501.20

—

(1630)

0.801.10

—0.90

(1540)

0.700.80

———

(1130)

1.300.80

0.50—

(1430)

29.6.81

2.202.20—

0.60—

(1120)

0.800.70

——

(1635)

0.700.10

———

(1545)

0.700.601.40_—

(1440)

2.9.81

1.45 + 0.352

(0900) 3

1.65 ±0.42(1000)

4.10.04

—0.851.20

(1635)

0.68 ±0.040.90 ±0.28

——

(1100)

0.60 ±0.254.00 ±0.016.00 ±1.35

——

(1400)

0.90 ±0.04

1.70±0.12—

(1200)

22.9.81

0.70±0.09(0900)

1.15±0.20(1000)

3.85 ±0.390.70 ±0.07

—0.82±0.180.68±0.15

(1500)

0.63 ±0.200.68 ±0.03

——

(1224)

0.58 ±0.050.30 ±0.08

———

(1400)

0.60 ±0.021.03±0.33

—0.40 ±0.01

___(1305)

11.12.81

0.79 ±0.25(1000)

4.116.50

—6.19

—(1515)

0.65

0.60——

(1400)

_

5.42———

(1315)

4.116.50

6.19—

(1130)

24.12.81

0.23±0.16(0900)

0.53 ±0.01

1.30±0.601.64±0.07

—

—(1145)

3.48 ±0.60—

1.87±0.19——

(1450)

3.002.16

—2.961.18

(1345)

1.40 ±0.050.90 ±0.20

4.35 ±0.05—

(1250)

Overall mean

0.79

1.03

2.15

1.06

2.04

1.96

0

a25

521O*i

wm

29ftwu

a>><

TABLE 2Dissolved oxygen and pH profiles at the sampling stations

Sampling Date

Station Depth (m)

CB 0.55.0

KB 0.55.0

29/4/81

pH DO 1

2

- -

29/6/81

pH DO

— —

— —

2/9/81

pH DO

- 0- 0

22/9/81

pH DO

7.006.56 -

0.66

11/12/81

pH DO

6.87 -

- -

24/12/81

pH

6.83

7.02

DO

0.600.40

0.200.25

0.51.05.07.0

10.012.7

7.51

7.907.91

3.50

5.605.60

7.07

7.043.45.75.96.06.0

7.16

7.63

7.85

1.501.703.25

3.90

7.19

7.74

7.91

1.952.25

4.05

7.24 7.352.25- 2.25 -

7.55 3.90 7.543.75

7.61 3.60 7.66

1.051.001.505.003.90

so©

OISO

i

ii

in

IV

12.5

1 = mg/e2 = not determined

0.51.05.07.08.08.5

0.51.05.06.07.0

10.015.0

0.51.05.0

10.012.514.0

8.03—

7.96—

7.93—

8.00—

8.018.03

——-

7.99—

7.897.99

——

8.10

5.70—

5.40—

7.40—

6.206.20

——-

6.40—

5.75.5

——

_7.92———

7.93

7.96————-

7.877.907.887.89—

5.70——

5.605.60

6.205.805.805.80

—-

6.85.85.8

——

7.84_

7.88———

7.78—

7.95——

8.14—

6.76_

7.867.85

—

3.903.803.613.61

——

5.655.555.60

——

5.60—

5.254.804.804.70

——

7.96—

8.07——_

7.94

—————

8.00—

8.128.17

—

4.554.654.40

—4.45

4.905.00

—5.00—

4.904.80

5.405.40

—5.20

——

_—

7.54—

7.54—

8.20—

8.18—_——

8.158.05

_

—

3.064.10

—4.10

—

5.005.055.15

5.30——

.4.105.205.20

——

8.24——

8.22—-

8.34_

8.34—_

8.34—

8.32—

8.308.32

——

4.804.904.905.00

——

5.105.105.505.105.105.60

-

5.05.04.95.305.70—

' • - < • •

• ; . ; ,

r

za

9a

DISTRIBUTION OF MERCURY IN THE KELANG ESTUARY

TABLE 3Total mercury content in the sediments of the Kelang estuary

(mg/kg wet sediment)

Samplingdate

29/4/1981

2/9/1981

22/9/1981

11/12/1981

24/12/1981

Mean

0.

0.

0.

C.B.

—

-

42 ±0 .

57 ±0.

78 ±0.

0.45

01 '

04

05

0.

0.

0.

K

51

35

44

0

B.

—

-

± 0

± 0

± 0

.43

.02

.03

.03

0.

0.

0.

0.

0.

Station

I

35 ±0,01

55 ±0.02

16±0.01

22 ±0.02

49 ±0.02

0.35

0.

0.

0.

0.

II

36 ±0.

32 + 0.

08 ±0.

14±0.

0.21 ±0.

0.22

04

01

01

02

02

0.

0.

0.

0.

0.

Ill

19 ± 0.01

36 ±0.03

07±0.01

03±0.01

18 ±0.02

0.17

IV

0.14 i 0.01

0.40 + 0.03

0.09 ±0.01

0.08 ±0.01

0.32+0.02

0.21

= MeanS.D.

a.6

I )2

28

k28.2.82

\

T X 26.2.82

A V

\l N KV • W 9

V/

0900 1360 2100 23001700

Time, hour

Fig. 1: Hourly monitoring of total mercury in thesurface water of Station KB

Kelang River; Station I is partially mixed, andthe rest of the stations are well mixed. There-fore, owning to the sea water dilution, one wouldexcept the mercury level at Stations CB and KBto be higher than that at Station I and muchhigher than that of the other estuarine stations.However, higher mercury levels were found inthe estuarine stations than that in the fresh waterstations. This indicates that there are possiblysome prosesses which result in enrichment of thesea water with mercury. The hourly monitoringof mercury at Station KB (Figure 1) indicatedthat there was some heavy point source dischargeof mercury into the river and this seemed to

happen in the afternoon. However, owing to thehigh tidal current dilution, this amount ofmercury elevation could not represent the mainsource of mercury enrichment in the estuarinewater.

The mercuric ions have a strong affinity forsuspended matter under low redox potentialconditions (Khalid et ai, 1977; Andersson,1979), The adsorbed mercuric ions are found tobe released into the water when the redox poten-tial of the water increases. The Kelang River isheavily polluted by domestic sewage and siltation(Law, 1980 and 1983). The condition of theKelang River water will therefore favour theadsorption of mercury in the water by suspendedmatter. When the adsorbed mercury reaches theestuary, it can be expected to be leached backinto the oxygenated sea water. This may explainwhy a high mercury level was found in theKelang estuary, despite the high tidal currentdilution observed there. In addition, underaerobic conditions with pH ranges between 5 to9, mercury in organic-rich sediment could bemethylated to methyl mercury by micro -organisms, and released in to the water (Beijerand Jernelov, 1979). As the Kelang estuarinesediment contains 0.58% to 2.20% organiccarbon (at stations II, III and IV), theoxygenerated bottom sea water, with a pH ofaround 8 (Table 2), will favour the mercury bio-

PERTANIKA VOL. 10 NO. 2, 1987 179

A.T. LAW AND SINGH

methylation process. Thus, the released methyl-mercury will further enrich the mercury level inthe water.

The differences between the mercury con-tent in riverine and estuarine sediments (Table3) seem to support the mercury desorption andbiomethylation process hypotheses. The mercurycontent in the estuarine sediment was signifi-cantly lowef than that detected in the riverinesediment. These results may indicate that someof the mercury adsorbed on the riverinesediment was released after reaching the estuary.

During the period of this study, Takeda etaL, (1984) investigated the mercury distributionin the Straits of Malacca and South China Sea.Mean levels were found to be 2.0ng/l and2.4ng/l respectively. The mercury level in theKelang estuarine water (mean 1690ng/l) is 845times higher than that in the Straits of Malacca,located just outside the estuary, and 704 timeshigher than that in South China Sea. Themercury level in the Kelang estuary is also muchhigher than that detected in the TurkishMediterranean coastal waters (15 to 120ng/l)(Tuncel et aL, 1980), in the Mersey estuary,U.K. (0.74/ig/l) (Airey and Jones, 1982), and inthe Delaware Bay (0.08 to 0.6jig/l) (Lepple,1973). This study therefore reveals that Kelangestuary carries some degree of mercury pollu-tion. The mercury incipient lethal level forMacro braehium rosenbergti larvae is 42p.g/l(Piyan, et aL, 1985) and that for marine plank-ton and molluscs is between 1 and 5jig/l (Patin,1982). The Kelang estuarine water therefore isstill considered safe for use in a Macro brae hiumrosenbergti hatchery or in mariculture.

ACKNOWLEGEMENTSThe authors would like to thank the Shah-bandar, Pelabuhan Kelang for his permission touse the Department's boat for sampling, Dr. IanG. Anderson for his comments on the paper,Encik Azahar Othman for his technical assis-tance, and Puan Bad an ah Mohd. Yusof fortyping the manuscript.

This project was funded by UniversitiPertanian Malaysia.

REFERENCES

AIREY, D. and P.D. JONES. (1982): Mercury in RiverMersey, its estuary and tributaries during 1973and 1974. Water Res. 16: 565-577.

ANDERSSON, A. (1979): Mercury in soils. In: TheBiogeochemistry of Mercury in the Environment.Nriagu, J.O. (ed.). Elsevier/Northern-HollandBiomedical Press, Amsterdam, New York,Oxford, p. 80-112.

BABJI, A.S., M.S. EMBONG and Z. AWANG. (1983):Monitoring of heavy metal contents of coastalwater fishes in Peninsular Malaysia. Preprint: AnInternational Conference on Development andManagement of Tropical Living AquaticResources. August 2 - 5 , 1983. UniversitiPertanian Malaysia, Serdang, Selangor.

BARLETT, P.D., PJ. CRAIG and S.F. MORTON. (1978):Total mercury and methyl mercury levels inBritish estuarine and marine sediments. SetTotal Environ. 10:245-251.

BEIJER, K. and A. JERNELOV. (1979): Methylation ofmercury in aquatic environment. In: The Biogeo-chemistry of mercury in the Environment.Nriagu, J.O. (ed.). Elsevier/Northern-HollandBiomedical Press, Amsterdam, New York,Oxford, p. 203-230.

Brrc. (1979): Standardization of methods for thedetermination of traces of mercury. Part 5.Determination of total mercury in water. Anal.Chimica. Ada. 109: 209-228.

CAMPBELL,J.A., E.Y.L. CHAN.J.P. RILEY, P.C. HEADand P.D. JONES. (1986): The distribution ofmercury in the Mersey Estuary. Mar. Pollut.Bull. 17:36-40.

CHAN, K.C., M.M. DURANDEAU and L.Y. GOH.(1978): Heavy metals pollution in the KelangRiver, Malaysia. MaLJ. Sci. 5(B): 137 -141 .

CHIA, J.S. and S.L. TONG. (1981): Mercury content offish from the river mouth of Sungei Kelang.MARDIRes. Bull. 9: 72-77.

GREIG, R.A. and DR. WENZLOFF. (1977): Tracemetals in Finfish from the New York Bight andLong Island Sound. Mar. Pollut. Bull. 8: 198 -204.

ISKANDAR, I.K., J.K. SYERS, L.W. JACOBS, D.R.KEENEY and J.T. GILMOUR. (1972): Determina-tion of total mercury in sediments and soils.Analyst. 97:388-393.

JOTHY, A.A., E. HUSCHENBETH and U. HARMS.(1983): On the detection of heavy metals, organo-chlorine pesticides and polychlorinated biphenylsin fish and shellfish from the coastal waters otPeninsular Malaysia. Arch. Fischwiss. 33(3):161-206.

180 PERTANIKA VOL. 10 NO. 2, 1987

DISTRIBUTION OF MERCURY IN THE KELANG ESTUARY

KHALID, R.A., R.P. GAMBRELL and W.H. PATRICK.JR. (1977): Sorption and release of mercury byMississippi River sediment as affected by pH andredox potential. In: Biological Implications ofMetals in the Environment. Drucker, H., andWildung, R.E. (eds.) National Technical Infor-mation Service, U.S. Department of Commerce,Springfield, Virginia. 862 pp.

KijrfBOE, T., F. MOHLENBERG and H. RHSCIRD(1983): Mercury levels in Fish, Invertebrates, andsediment in a recently recorded polluted area(Nissum Broad, Western Limfjord, Denmark).Mar. Pollut. Bull. 14: 21-24.

LANGSTON, W.J. (1982): The distribution of mercuryin British estuarine sediments and its availabilityto deposit-feeding bivalves. / . Mar. Bio. Asso.UK. 62: 667 - 684.

LAW, A.T. (1980): Sewage pollution in Kelang Riverand its estuary. Pertanika 3(1): 13 - 19.

LAWf A.T. (1983): Monitoring of sewage pollution inthe estuarine and coastal water of Port Kelang,Malaysia. Preprint: An International Conferenceon Development and Management of TropicalLiving Aquatic Resources. August 2 - 5 , 1983,Universiti Pertanian Malaysia, Serdang, Selangor.

LAW, A.T. and A. SINGH. (1986): Distribution ofManganese, iron, copper, lead and zinc in waterand sediment of Kelang Estuary. Pertanika 9:209-217.

LEPPLE, F.K. (1973): Mercury in the environment. Aglobal review including recent studies in theDelaware Bay region. Univ. of Delaware,Newark, Delaware, U.S.A. 75 pp.

LlONG, P.C. (1983): Heavy metals in shellfish from thenorthern part of Malacca Straits. Preprint: An

International Conference on Development andManagement of Tropical Living AquaticResources. August 2 - 5 , 1983. UniversitiPertanian Malaysia, Serdang, Selangor.

MEDINA, J., F. HERNANDEZ and A. PASTOR. (1986):Determination of mercury, cadmium, chromiumand lead in marine organisms by flameless atomicabsorption spectrophotometry. Mar. Pollut. Bull.17:41-44.

PATIN, S.A. (1982): Pollution and the BiologicalResources of the Oceans. London: ButterworthScientific, 287 pp.

PlYAN, B.T., A.T. LAW and S.H. CHEAH. (1985):Toxic levels of mercury on sequential larval stagesof Macrobrachium rosenbergii (de Man), Aqua-culture 46: 353 -359.

SAKAMOTO, H. (1985): The distribution of mercury,arsenic, and antimony in sediments of KagoshimaBay. Bull. Chem. Soc.Jpn. 58: 580-587.

SIVALINGAM, P.M. and AHZURA BINTI SANI. (1980):Mercury content in hair from fishing commu-nities of the state of Penang, Malaysia. Mar.Pollut. Bull. 1 1 : 1 8 8 - 1 9 1 .

TAKEDA, H., A. TSURUTA, A. KATAOKA, K. NAGATOMO. and T. TOMITA. (1984): Mercury level ofsea water and suspended matter of the China Sea,the Strait of Malacca, and the Indian Ocean. TheJournal of Shimonoseki University of Fisheries.32(3): 57-65 .

TUNCEL, G., G. RAMELOW and T.I. BALKAS. (1980):Mercury in water, organisms and sediments froma section of the Turkish Mediterranean Coast.Mar. Pollut. Bull. 11:18-22.

(Received 23 July, 1986)

PERTANIKA VOL. 10 NO. 2, 1987 181