Contamination of butyltin compounds in Malaysian marine environments

Environmental Pollution 130 (2004) 347e358

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Contamination of butyltin compounds inMalaysian marine environments

Agus Sudaryantoa, Shin Takahashia, Hisato Iwataa,Shinsuke Tanabea,*, Ahmad Ismailb

aCenter for Marine Environmental Studies, Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577, JapanbFaculty of Science and Environmental Studies, University Putra Malaya, Malaysia

Received 30 June 2003; accepted 9 January 2004

‘‘Capsule’’: Lack of any regulation of TBT clearly resulted in a heavy contamination of BTs in Malaysia.

Abstract

Concentration of butyltin compounds (BTs), including tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) and totaltin (SSn) were determined in green mussel (Perna viridis), 10 species of muscle fish and sediment from coastal waters of Malaysia.

BTs were detected in all these samples ranging from 3.6 to 900 ng/g wet wt., 3.6 to 210 ng/g wet wt., and 18 to 1400 ng/g dry wt. formussels, fish and sediments, respectively. The concentrations of BTs in several locations of this study were comparable with thereported values from some developed countries and highest among Asian developing nations. Considerable concentration of BTs in

several locations might have ecotoxicological consequences and may cause concern to human health. The parent compound TBTwas found to be highest than those of its degradation compounds, DBT and MBT, suggesting recent input of TBT to the Malaysianmarine environment. Significant positive correlation (Spearman rank correlation: r2=0.82, P!0.0001) was found between BTs and

SSn, implying considerable anthropogenic input of butyltin compounds to total tin contamination levels. Enormous boatingactivities may be a major source of BTs in this country, although aquaculture activities may not be ignored.� 2004 Elsevier Ltd. All rights reserved.

Keywords: Butyltins; Total tin; Contamination; Fish; Sediment; Mussel; Malaysia

1. Introduction

Organotin compounds are in the limelight in marinepollution studies due to their bioaccumulative natureand deleterious effects on the aquatic organisms. Thesecompounds have been used commercially for many yearsin a variety of applications such as polyvinyl chloride(PVC) stabilizers, industrial catalysts, wood preserva-tives, and biocides. Particularly, tributyltin (TBT) hasbeen used for almost three decades as an effectiveantifouling agent added in marine paint formulationsused on pleasure boats, ships, vessels, docks, fish nets,and also as lumber preservatives and slimicides in cool-ing system (Blunden and Evans, 1990; Fent, 1996). The

* Corresponding author. Tel./fax :C81-89-927-8171.

E-mail address: [email protected] (S. Tanabe).

0269-7491/$ - see front matter � 2004 Elsevier Ltd. All rights reserved.

doi:10.1016/j.envpol.2004.01.002

aquatic pollution by organotin compounds mainly arisefrom the direct exposure of TBT. Various biologicaleffects due to exposure to TBT have been well docu-mented. Particularly, low tropic organisms were found tobe acutely sensitive to TBT (Beaumont and Newman,1986; Bushong et al., 1988; Hall, 1988). TBT affectsmollusks in various ways such as shell malformation inoysters (Waldock et al., 1996; Alzieu, 1996), mortality ofthe larvae of mussels (Beaumont and Budd, 1984) andendocrine disruption including imposex in gastropods(Bryan and Gibbs, 1991; Matthiessen and Gibbs, 1998).TBT also exhibit toxic effects in fish particularly duringearly life stages (Fent, 1992), which may result in sexhormone imbalances (Fent et al., 1998). Due to its per-sistency and biological effects on various organisms,many developed countries have banned and/or restrictedTBT usage for boating and aquaculture purposes fromearly 1980s (Fent, 1996; Champ, 2000).

348 A. Sudaryanto et al. / Environmental Pollution 130 (2004) 347e358

In Malaysia, similar to other Asian countries exceptJapan and Hong Kong, there is no specific legislationcontrolling the usage of TBT (Champ, 2000). Malaysia issurrounded by the busiest waterways such as MalaccaStrait and South China Sea, which is recognized as aheavy shipping traffic line in Southeast Asia. In fact, thiscountry has better economic status than other Asiandeveloping nations (Sudaryanto et al., 2002). Therefore,this situation may lead to heavy contamination by orga-notins in the environment as well as their potentialpollution sources. Hashimoto et al. (1998) has reportedhigh levels of butyltin compounds in seawater from abusytanker route of the Strait of Malacca. The occurrences ofTBT have also been reported in the sediments andbivalves from few selected areas of Peninsular Malaysia(Tong et al., 1996). TBT has been detected both in naturaland cultured mussels purchased from market (Tonget al., 1996). Furthermore, specific contamination of TBTin coastal waters of Malaysia has been shown by theappearance of their field ecotoxicological impacts, theso-called imposex in gastropods from coastal waters ofMalacca Strait (Ellis and Pattisina, 1990; Swennen et al.,1997; Tan, 1999). More recently, our study has indicatedwidespread occurrence of BTs in the marine environmentof Malaysia especially in mussels collected along coastalwaters of this country (Sudaryanto et al., 2002). Despitethis finding, however, there is still lack informationconcerning its contamination in economically importantfish and sediment. Thus, the investigation on BTs in fishand sediment of Malaysian marine environment is anurgent need at the present circumstances.

The present paper attempts to report the extent ofrecent contamination and distribution of butyltin com-pounds in the Malaysian marine environment. Concen-trations of butyltin compounds (BTs) including TBT and

its breakdown products, di- (DBT) and monobutyltin(MBT), and total tin (

PSn) were determined in fish and

sediment samples collected from the coastal waters ofMalaysian Peninsula. To clearly understand the contam-ination status in Malaysian marine environment, ourpreviously reported data on green mussels (Perna viridis)(Sudaryanto et al., 2002) were also compared with thepresent study. The contribution by anthropogenic inputof tin compounds in total tin (

PSn) contamination in

fish and mussels was also evaluated. This study was con-ducted as a part of ‘‘Asia-Pacific Mussel Watch Project’’,which is a global monitoring program on marine pol-lution principally by using ‘mussels’ as bioindicators.

2. Materials and methods

2.1. Samples

Fish and sediment samples were collected along thecoastal waters of Malaysia during 1997e1998 (Tables 1and 2). The sampling locations included urban pop-ulation centers, harbors, recreational beaches andmarine aquaculture areas (Table 2). Sediments werecollected using Grab samplers from 13 locations incoastal waters of the Peninsula Malaysia in the periodfrom December 1997 to September 1998. The fish werecaught by gillnet and seines from six locations in thePeninsula during 20e23 September 1998. All the sam-ples were covered with aluminum foil and stored inpolyethylene bags, kept in a cooler box with ice or dryice, transported to laboratory in Japan, and then im-mediately kept in a deep freezer. Fish species wereidentified based on Allen (1997), and biometric measure-ments were made. Ten species of fish were identified and

Table 1

Sampling locations, date and biometry of marine fish collected from coastal waters of Malaysia

Location Date Common name Species Habitat na Length

(cm)

Weight

(g wet wt.)

Cabang Tiga

(Kotabahru)

980920 Mackerel tuna Euthynus affinis Offshore, pelagic 3 39e41 800e1000980920 Finny scad Megalaspis cordyla Coastal, pelagic 3 24e26 157e214

980920 Rosy threadfin bream Nemipterus bathybius Coastal, demersal 2 20e21 94e105

Langkawi 980920 Finny scad Megalaspis cordyla Coastal, pelagic 2 27e27 194e203980920 Purse eye scad Selar crumenthalmops Coastal, pelagic 2 18e27 50e57

980920 Patterned tongue sole Paraplagusia bilineata Coastal, demersal 3 23e26 42e76

980920 Redtail scad Decapterus kurroides Coastal, pelagic 3 15e18 29e62

Kuala Terengganu 980921 Purse eye scad Selar crumenthalmops Coastal, pelagic 3 21e22 98e100980921 Redtail scad Decapterus kurroides Coastal, pelagic 3 24e25 185e209

Mersing (Johore) 980922 Spotted javelinfish Pomadasys kaakan Coastal, demersal 2 20e21 125e151

980922 Longed jawed mackerel Rastrelliger kanagurta Coastal, pelagic 3 20e21 95e108

980922 Purse eye scad Selar crumenthalmops Coastal, pelagic 3 21e23 114e134Parit Jawa (Johore) 980922 Purse eye scad Selar crumenthalmops Coastal, pelagic 3 21e22 111e116

980922 Double spotted queenfish Scomberoides lysan Coastal, pelagic 3 28e29 130e181

Port Dickson

(Negeri Sembilan)

980923 Black pomfret Parastromateus niger Continental, demersal 3 21e22 192e210

980923 Finny scad Megalaspis cordyla Coastal, pelagic 3 25e29 169e239980923 Purse eye scad Selar crumenthalmops Coastal, pelagic 3 17e18 60e73

a nZnumber of individual samples.

349A. Sudaryanto et al. / Environmental Pollution 130 (2004) 347e358

Table 2

Sampling locations and date of collection of sediments in coastal waters of Malaysia

Location Site codea Date Area description

Sangkar Ikan-1, Langkawi MYKESI-1 971225 Urban area, aquaculture area

Sangkar Ikan-2, Langkawi MYKESI-2 980920 Urban area, aquaculture area

Tg. Dawai, Kedah MYKETD 971226 Fishery, recreational beach, aquaculture area

Penang Bridge-1, Penang MYPEPB-1 970314 Port, industrial area, urban area

Penang Bridge-2, Penang MYPEPB-2 980921 Port, industrial area, urban area

Port Klang, Selangor MYSEPK 980927 Container cargo port

Port Dickson, Negeri Sembilan MYNSPD 980819 Old port and refinery

Malacca, Melaka MYMAMC 980922 Industrial and urban area

Tg. Piai, Johore MYJBTP 980530 Port, aquaculture

Pasir Puteh-2, Johore Bahru MYJBPP-2 980530 Port, shipping line, industrial area, urban area

Pasir Puteh-3, Johore Bahru MYJBPP-3 980923 Port, shipping line, industrial area, urban area

Pantai Lido-2, Johore Bahru MYJBPL-2 980530 Port, shipping line, industrial area, urban area

Pantai Lido-3, Johore Bahru MYJBPL-3 980923 Port, shipping line, industrial area, urban area

a First, second and third letters indicate the abbreviation of country, province or city and local name, respectively.

their muscle tissues were separated from each individualand frozen at-20 (C until chemical analysis. Details ofsampling locations and biological data of fish and sedi-ment are shown in Fig. 1, Tables 1 and 2, respectively.

2.2. Chemicals analysis

Butyltin compounds were analyzed following themethod described by Takahashi et al. (1999). In brief,approximately 2 g of wet tissue samples of fish or 5 g ofsediment samples were individually homogenized with70 ml of 0.1% tropoloneeacetone and 5 ml of 2 N HCl.After centrifugation, the supernatant was transferred to100 ml of 0.1% tropoloneebenzene, and moisture in thesolvent was removed with anhydrous Na2SO4. After

concentrating the extract using a rotary evaporator, BTsin benzene were propylated by adding 10 ml of n-propylmagnesium bromide (w1 mol/l in tetrahydrofuran,Kanto Chemical, Tokyo, Japan) as a Grignard reagent.Excess reagent was destroyed with 1 N sulfuric acid, andthe propylated mixture was transferred to 10% benzene/hexane. The solution was purified on a Florisil-packedglass column (Wako Pure Chemical, Tokyo, Japan) andeluted with hexane. The final hexane solution wasconcentrated and injected into a gas chromatograph(Hewlett-Packard 5890 series II, Palo Alto, CA, USA)equipped with flame photometric detector (GCeFPD)and a tin mode filter (610 nm) for the analysis of BTs. Afused silica capillary column (30 m length ! 0.25 mmi.d., 0.25 mm film thickness) coated with DB-1 (100%

Fig. 1. Map showing sampling locations of fish and sediments in the present study and mussels from our earlier study in coastal waters of Malaysia.

350 A. Sudaryanto et al. / Environmental Pollution 130 (2004) 347e358

dimethyl polysiloxane, J&W Scientific, Folsom, CA,USA) was used for separation. The flame photometerwas equipped with a 610-nm band-pass filter, selectivefor tin-containing compounds. Identification of BTs wasmade by assigning peaks in samples to the correspond-ing ones in the external standard.

The procedure for BTs in sediment was the same asfor the tissue samples. However, to avoid the inter-ference of sulfur in the quantification of BTs by GCeFPD, a mixture of tetrabutyl ammonium and sodiumsulfide was added during the extraction of BTs by 0.1%tropolone/benzene.

Standard mixtures were prepared with every set ofsample analysis by propylating the known BT mixturesspiked on the liver of Antarctic minke whale andunpolluted-sediment for biological and sediment samplesanalysis, respectively, which were previously found tocontain only trace levels of BTs. In addition, hexyl-TBTwas added to all the samples as an internal standard. Therecoveries of MBT, DBT, and TBT dissolved and spikedto liver samples of Antarctic minke whale (nZ5) were111G 17%, 121G 16%, and 92G 7.7%, and to unpol-luted-sediment (nZ4) were 85G 10%, 94G 6.8% and92G 5.0%. Concentrations of BTs in all the sampleswere expressed as nanogram of BT per gram on wetweight basis for fish and dry weight basis for sedimentsamples without any correction for recovery.

The analytical procedure for total tin was based onthe method described elsewhere (Saeki et al., 1998; Leet al., 1999) with minor modification. Briefly, tissuesamples were dried at 80 (C for 12 h and then homo-genized into powder. About 0.1 g of the powderedsample was weighed into 8-ml polytetrafluoroethylene(PTFE) tubes. The digestion was carried out with puri-fied HNO3 (w63%) in a microwave oven for 10 min at200 W three times. When digestion was completed, thesample was transferred into a measuring flask anddiluted with Milli-Q water (Millipore, Bedford, MA,USA). Tin concentrations in samples were determinedusing the inductively coupled plasma mass spectrometry(ICP-MS) (Hewlett-Packard, HP 4500). Detection limitwas 10 ng Sn/g on a dry weight basis. Accuracy of theanalytical method was checked using a certified refer-ence biological material (NIES No. 11) and the recoveryof Sn was 107G 1.2% (nZ3).

2.3. Statistical analysis

Statistical analysis was performed using StatView(version 5.0, SAS� Institute, Cary, NC, USA). ManneWhitney U test was used for the detection of statisticaldifferences in BTs concentrations between sediment andmussel samples. The Spearman rank correlation wasused to examine the correlation between concentrationsof SBTs and SSn. A probability value of P!0.05 wasconsidered as statistically significant.

3. Results and discussion

3.1. Concentrations

Butyltin compounds (BTs) including MBT, DBT andTBT were detected in fish muscle and sediments from alllocations investigated (Tables 3 and 4). Comparing theresults reported previously for sea water, sediments,mussels and cockles (Tong et al., 1996; Hashimoto et al.,1998; Sudaryanto et al., 2002), it is apparent that BTscontamination is widely distributed along coastal watersof Malaysia and has spread to a wide range of environ-mental media and biota. Among the BTs concentrationin fish, TBT ranged from 2.4 to 190 ng/g wt, DBT from!1.3 to 13 ng/g wet wt. and MBT from 2.3 to 7.4 ng/gwet wt. (Table 3). Further, the concentration of BTs insediments were in the range of 2.8e1100 ng/g dry wt. forTBT, 3.8e310 ng/g dry wt. for DBT and 5.0e360 ng/gdry wt. for MBT (Table 4). The composition pattern wassimilar to those found in many biological samples fromother Asian countries (Kan-atireklap et al., 1997a;Prudente et al., 1999; Sudaryanto et al., 2002; Honget al., 2001), in which the parent TBT was generallyhigher than its degradation products, DBT and MBT,thus reflecting a same status of TBT usage in this regionof the world at present. Fish has been suggested to havegreater metabolic capability than bivalves (Lee, 1996)due to the presence of a high level of cytochrome P450-dependent mixed-function oxygenase enzymes (MFO),which play a role in the hydroxylation of TBT. Thus, thehigh concentration of TBT found in the present studysuggests fresh inputs of TBT and the presence of recentsources along coastal waters of Malaysia.

The total concentrations of BTs (TBTCDBTCMBT)in the muscle of fish and sediments were from 5.3 to 210ng/g wet wt. and from 14 to 1400 ng/g dry wt, respectively(Tables 3 and 4). Consistently, the levels of BTs found inmussels (3.6e900 ng/g wet wt.) (Sudaryanto et al., 2002),were in the higher range among Asian developing coun-tries, and somewhat comparable with those in some de-veloped nations (Tables 5 and 6). While there is anapparent declining trend of BTs in the environment ofdeveloped countries as a consequence of their restrictionor ban (Fent, 1996), our results suggest a continuousinput of BTs into the environment in some Asiancountries without any regulation on TBT usage, inclu-ding Malaysia. Lack of any regulations of TBT clearlyresulted in a heavy contamination of BTs in Malaysia.

3.2. Geographical variation

Similar to mussels (Sudaryanto et al., 2002), concen-tration of BTs found in fish and sediment also appearedto reflect the background levels in the sampling loca-tions, suggesting that contamination by BTs is localized.In order to deeply understand the spatial distribution of

351A. Sudaryanto et al. / Environmental Pollution 130 (2004) 347e358

Table 3

Concentrations of butyltin compounds (ng/g wet wt.) and total tin (ng Sn/g dry wt.) in fish collected from coastal waters of Malaysia

Location/common name MBT DBT TBT SBTs SBTsa SSna TBT/SBTs

(%)

SBTsa/SSna

(%)

Kotabahru

Mackerel tuna 3.6 6.3 71 80 120 210 89 57

Finny scad 2.6 1.8 4.2 8.4 21 110 50 19

Rosy threadfin bream 3.9 1.6 2.4 7.8 16 150 31 11

Langkawi

Finny scad 3.9 2.6 8.3 15 27 160 55 17

Purse eye scad 3.9 2.0 15 21 36 120 71 30

Patterned tongue sole 2.5 !1.3 2.8 5.3 17 110 48 15

Redtail scad 2.3 2.3 10 15 27 68 67 40

Kuala Terengganu

Purse eye scad 3.4 2.1 13 18 32 70 72 45

Redtail scad 5.8 1.9 8.7 17 32 78 51 41

Mersing

Spotted javelinfish 4.2 1.8 3.8 10 24 240 38 10

Longed-jawed mackerel 4.2 6.2 69 78 120 180 88 67

Purse eye scad 4.9 4.8 15 24 45 260 63 17

Parit Jawa

Purse eye scad 5.7 13 72 90 150 230 80 65

Double spotted queenfish 6.3 11 190 210 390 730 90 53

Port Dickson

Black pomfret 6.3 2.9 36 45 80 130 80 62

Finny scad 7.4 11 59 78 130 270 76 48

Purse eye scad 3.9 2.5 30 37 60 82 81 73

a Expressed as ng Sn/g dry wt.

BTs contamination in Malaysian coastal waters, con-centrations of total BTs including the data in ourprevious report (Sudaryanto et al., 2002) were plotted(Fig. 2). Sites with consistently elevated concentrationsof BTs in fish, sediment and mussels were found alongthe coast of Malacca Strait, particularly in locationshaving intensive maritime activities (Penang, Johore andJohor Bahru). Especially, highest concentration of BTswas found in sediments (1400 ng/g dry wt.) and fish (210ng/g wet wt.) in the samples collected in the narrowestarea of Johor Strait and Malacca Strait (MYJBPL-2,Parit Jawa) where large harbors and major shipping

traffic areas are located. In addition, a positive correla-tion was found between the concentrations of BTs insediments and mussels collected from the same site(ManneWhitney U test: r2=0.54, P!0.05, Fig. 3). Asmentioned earlier in this article, Hashimoto et al. (1998)also observed higher concentration of TBT in seawaterin areas of heavy shipping traffic lines of Malacca Strait.This observation is also in accordance with the resultsfound in fish of this study.

Sediments taken from other locations such as areasof recreational beach, areas of small fishing boatsand small scale aquaculture locations revealed lower

Table 4

Concentrations of butyltin compounds (ng/g dry wt.) in sediments from coastal waters of Malaysia

Location Site code MBT DBT TBTP

BTs TBT/P

BTs (%)

Sangkar Ikan-1, Langkawi MYKESI-1 8.9 4.3 2.8 16 18

Sangkar Ikan-2, Langkawi MYKESI-2 12 5.7 4.8 23 21

Tg. Dawai, Kedah MYKETD 5.0 3.8 5.1 14 36

Penang Bridge-1, Penang MYPEPB-1 79 150 230 460 50

Penang Bridge-2, Penang MYPEPB-2 26 18 29 74 39

Port Klang, Selangor MYSEPK 6.0 5.1 16 27 59

Port Dickson, Negeri Sembilan MYNSPD 17 5.8 5.6 29 19

Malacca, Melaka MYMAMC 20 17 13 50 26

Tg. Piai, Johore MYJBTP 39 25 42 110 38

Pasir Puteh-2, Johore Bahru MYJBPP-2 22 12 110 140 79

Pasir Puteh-3, Johore Bahru MYJBPP-3 360 310 270 940 29

Pantai Lido-2, Johore Bahru MYJBPL-2 160 140 1100 1400 79

Pantai Lido-3, Johore Bahru MYJBPL-3 77 33 45 160 28

352 A. Sudaryanto et al. / Environmental Pollution 130 (2004) 347e358

Table 5

Concentrations (ng ion/g wet wt.) of MBT, DBT and TBT residues in the muscle tissues of fish from various regions of the world*

Location (year surveyed) MBT DBT TBT References

Alaska, USA 198 (1981e1984) naa na 280e900 Short and Thrower, 1986

Coos Bay, USA (1992e1994) na na !2e130 Elgethun et al., 2000

The Netherlands (1993) 23e41 13e183 9.2e67 Stab et al., 1996

River Elbe and North Sea, German (1993) 89b 55b 66e490 Shawky and Emons, 1998

Baltic Sea, Poland (1997) 8.0e43 8.0e530 17e2700 Senthilkumar et al., 1999

Australia (1990e1992) !4.0e42 !0.36e3.1 !0.13e13 Kannan et al., 1995

Papua New Guinea (1990) !4.0e8.0 !0.36e0.98 !0.13e0.15 Kannan et al., 1995

The Solomon Island (1990) !40 !0.36e0.4 0.2e1.0 Kannan et al., 1995

India (1989) !5.6e78 !0.36e0.65 !0.13e1.6 Kannan et al., 1995

Bangladesh (1994) !5.6e170 !0.36e15 0.47e3.0 Kannan et al., 1995

Thailand (1994) !5.6 1.6e2.6 1.3e13 Kannan et al., 1995

Vietnam (1990) !5.6 !0.36e0.78 !0.13e0.90 Kannan et al., 1995

Indonesia (1991) !5.6e10 0.41e4.8 !0.13e3.7 Kannan et al., 1995

Taiwan (1990) !5.6e13 0.36e2.1 0.13e5.2 Kannan et al., 1995

Taiwan (1997) 2.8e11 5.8e16 ndc Hung et al., 1998

Japan (1992) na 3.9e49 8.9e450 Suzuki et al., 1992

Otsuchi Bay, Japan (1996) na na 10e20 Harino et al., 1998a

Osaka Bay, Japan (1996) 25e83 2.0e18 11e182 Harino et al., 1998b

Aomori, Japan (1996) nde20 nde50 nde240 Ueno et al., 1999

Malaysia (1998) 2.3e7.4 !1.3e13 2.4e190 This study

* All values originally reported as butyltin-Sn or butyltin-Cl concentration are converted here to butyltin ions.a naZno data available.b Maximum concentration.c ndZnot detected.

concentrations (Table 4, Fig. 2). The same situation wasfound in fish caught from the coastal waters at thenorthern areas of the Peninsula (Kotabahru, KualaTerengganu, and Mersing) (Table 3, Fig. 2) which hasrelatively lower boating activities and hence the fish hereaccumulated somewhat lower levels of BTs residues. Thelower levels of BTs were also recorded in mussels fromrural sites in Sabah at Kalimantan Island (Fig. 2).Considering the potential sources of BTs contamination,this observation was found to be similar to the findingsin developed countries in which significant TBT conta-mination was noticed in harbors, marinas, shipyardsand high boating activities (Fent, 1996). On the whole, itcan be suggested that, maritime activities, such as usageof TBT as biocide in antifouling paints on ship hullsand/or other marine structures in harbors contributes toheavy contamination of BTs in Malaysia. However,aquaculture activities in intensive culture areas mayalso contribute to BTs contamination sources in thiscountry since relatively high concentrations of BTs wereobserved in mussels collected from aquaculture site inLangkawi (140 ng/g wet wt.) (Sudaryanto et al., 2002).Similar situation of elevated concentrations of BTs inareas of fishery activitywere also found inThailand (Kan-atireklap et al., 1997a) and Hong Kong (Sudaryantoet al., 2002; Lau Wong, 1991). Therefore, TBT maybe used for aquaculture purposes in Asian developingcountries, including Malaysia. A possible contaminationsource of BTs in such areas could also be from the usageof MBT and DBT in plastic products as stabilizers andcatalyst.

3.3. Species-specific accumulation

Among fish, the pelagic fish ( finny scad, purse eyescad, redtail scad, long-jawed mackerel, double spottedqueenfish) accumulated BTs higher than demersalspecies (rosy threadfin bream, patterned tongue sole,spotted javelinfish). This might partially be attributableto the direct uptake of BTs released into water columnbefore deposition into the sediments. Noticeably, thetwo highest BTs concentrations were recorded in purseeye scad and double spotted queenfish purchased fromMersing site, the area of heavy ship traffic line atMalacca Strait. Thus, the distance to the source wouldplay a role in the accumulation pattern. In fact, almostall the demersal fish showed an accumulation patternsimilar to those in respective ambient sediment concen-trations. Interestingly, relatively higher concentrationsof

PBTs were recorded in fish caught at northern

waters with less maritime activities (mackerel: 80 ng/gwet wt. from Kotabahru and long-jawed mackerel: 78ng/g wet wt. from Mersing). According to the ecologicalstudies, both the species could be found throughout theoffshore region and they have long distance migrationbehavior (Allen, 1997). During migration, probably,they may integrate contaminants from a wide range ofgeographic area particularly from South China Sea, oneof the busy shipping traffic line. This seems to be aplausible explanation for elevated BTs in mackerel andlong-jawed mackerel caught in such a pristine area.Alternatively, these two species might have specificallylower metabolic capacities for BT compounds and hence

353A. Sudaryanto et al. / Environmental Pollution 130 (2004) 347e358

Table 6

Concentrations (ng ion/g dry wt.) of MBT, DBT and TBT residues in sediments from various regions of the world*

Location ( year surveyed) MBT DBT TBT References

East, Gulf and Pacific Coast, USA (1986e1991) naae95 na !10e770 Krone et al., 1995

Chesapeake Bay, USA (1986e1987) na na 4000 Espourteille et al., 1993b

Santa Monica and San Pedro Basin, USA (1991) ndce12 nde27 nde7.4 Venkatesan et al., 1998

Portland and Boothbay Harbor, USA (1990e1992) na 15e2240 24e12,400 Page et al., 1996

Sado Estuarine, Portugal (1986) nde2100 nde9600 nde520 Quevauviller et al., 1989

Western Mediterranean (1988) nde1591 nde960 nde9260 Tolosa et al., 1992

Sweden (1989e1990) na na 860e1480 Stuer-Lauridsen & Dahl, 1995

East Coast Estuaries, UK (1990) !1.5e260 !2.0e5800 !3e3900 Dowson et al., 1992

The Netherlands (1993) 15e1269 12e274 8.8e148 Stab et al., 1996

Southwest Spain (1993) 3.1e140 4.1e560 2.9e320 Gomez-Ariza et al., 1998

Auckland, New Zealand (1990) na na !4.9e3318 de Mora et al., 1995

New Zealand (1992e1994) na na !4.9e108,336 de Mora and Phillips, 1997

Coastal of Poland (1993e1995) 3.6e2960 nde5096 nde8540 Szpunar et al., 1997

Perth, Australia (1995) na na 1.0e1350 Burt and Ebell, 1995

Otsuchi Bay, Japan (1996) na na 10e640 Harino et al., 1998a

Otsuchi Bay, Japan (1995) na na 5.6e82 Takahashi et al., 1999

Osaka Port, Japan (1995e1996) na na 10e2100 Harino et al., 1998b

Hong Kong (1991) na na !9e1690 Lau Wong, 1991

Bahrain (1992) na na 128e1930 Hasan and Juma, 1992

Kyeonggi Bay, Korea (1995) na na 0.8e84 Kim et al., 1998

Chinhae Bay, Korea (1995) 59e1100 20e1100 10e800 Hwang et al., 1999

Coast of Thailand (1995) 7e410 2e1900 4e4500 Kan-atireklap et al., 1997b

Malaysia (1997e1998) 5.0e360 3.8e310 2.8e1100 This study

* All values originally reported as butyltin-Sn or butyltin-Cl concentration are converted here to butyltin ions.a naZno data available.b Maximum concentration.c ndZnot detected.

the higher amounts of TBT (90%) among the total BTswere noticed in their bodies.

3.4. Composition

As far as the concentration of BTs in fish samples,TBT was detected at almost all the locations at relativelygreater concentrations than DBT and MBT (Table 3).The average proportion of TBT in

PBTs in fish was

66%, whereas MBT and DBT were much lower(Table 3, Fig. 4). The compositional ratio of BTs wasin the order of TBTOMBTODBT. This pattern issimilar to BTs composition reported for mussels in ourearlier investigation (Sudaryanto et al., 2002). The aver-age proportion of TBT in mussels was reported as 71%to

PBTs (Fig. 4). As discussed above, the predominant

composition of TBT than other metabolic products inthese samples suggest fresh input of TBT into Malaysianmarine environment. However, a contrasting pattern ofBT composition was observed, in fish inhabiting bottomwaters (demersal), such as rosy threadfin bream, spottedjavelinfish and patterned tongue sole which containeda relatively larger proportion of degradation compounds(MBT and DBT) than those of pelagic fish. In fact, allthese fish are believed to be caught from relativelyunpolluted coastal waters with a minimal source of freshTBT input. This may also indicate that TBT has beendegraded during deposition and/or in the sediment.

Interestingly, the demersal fish, black pomfret from anarea of high maritime activity (Port Dickson) accumu-lated high proportion of TBT (80%) suggesting highinput of this contaminant in this location.

In contrast, in most of the locations (9 out of 13locations) generally MBT were occurred in highest pro-portion (up to 59%) than the parent compound insediment (Table 4). The average composition of TBT tototal BTs in sediment was low compared to those in fishand mussel (Fig. 4). The proportions of metaboliccompounds (DBTCMBT) in total BTs accounted for58e83% in these nine locations. Thus, TBT in sedimentsin several coastal areas of Malaysia seems to have beendegraded to the metabolic products resulting in elevatedMBT and DBT proportions. In fact, the occurrence ofhigher proportion of DBT and MBT in almost all thefishes inhabiting bottom layer (demersal), also supportthe above explanation. Interestingly, higher proportionsof TBT in sediment (50e79%) were also observed inareas of high maritime activities, such as Penang Bride,Port Klang and Johore Bahru (MYJBPL-1, MYJBPP-1,MYPEPB-1, and MYSEPK) (Table 4), suggesting heavyinput of TBT in these areas.

3.5. Ecotoxicological impacts and human health risk

From the ecotoxicological point of view, the con-tamination profiles of BTs in Malaysian environment,

354 A. Sudaryanto et al. / Environmental Pollution 130 (2004) 347e358

Fig. 2. Contamination levels ofP

BTs in mussel (ng/g wet wt.), fish (ng/g wet wt.) and sediment (ng/g dry wt.) in coastal waters of Malaysia.

particularly in hot spot areas may impose harmfuleffects to mollusks and other marine organisms. Pre-vious studies established that calcification of Crassostreagigas is inhibited at TBT concentration of O0.8 ng Sn/l(Chagot et al., 1990) and imposex is initiated at TBTconcentration of !1 ng Sn/l (Gibbs et al., 1987).Furthermore, an effect of immunomodulation in bluemussel have been observed at TBT and DBT concen-

Fig. 3. Correlation betweenP

BTs in mussel andP

BTs in sediment

from coastal waters of Malaysia.

tration as low as 1 ng Sn/l (St-Jean et al., 2002). Pageand Widdows (1991) also reported a threshold of TBTfor the ‘‘scope for growth’’ of blue mussel at approx-imately 2 mg/g dry wt. (=400 ng/g wet wt.). Based on invivo studies mentioned above, the reported concentra-tion of TBT (0.2e5.2 ng TBTCL/l) in seawater along theStrait of Malacca (Hashimoto et al., 1998) is highenough to cause imposex in gastropods, calcification ofoysters and immunotoxicity in mussels. In fact, imposexincidence in gastropods has already been reported atseveral locations of Malacca Strait (Ellis and Pattisina,1990; Swennen et al., 1997; Tan, 1999). The concen-trations of BTs in mussels from several locations of

Fig. 4. Percentage of TBT toP

BTs in fish, sediment and mussel from

coastal waters of Malaysia.

355A. Sudaryanto et al. / Environmental Pollution 130 (2004) 347e358

Malaysia were also close or higher than the thresholdvalue (Sudaryanto et al., 2002). In general, the environ-mental background data available at present may beindicative of the fact that ecotoxicological impacts ofBTs pollution may exist in Malaysia. Thus, in vitroecotoxicological studies on adverse effects of BTscontamination, particularly TBT and TPT (triphenyl-tin), a potential contaminant causing endocrine disrup-tion in bivalves are needed in Malaysian environment.

In this study, we calculated dietary intake of butyltinby human through seafood. The levels of BTs in fish andmussels were also compared with the tolerable averageresidue levels (TARL) of this country based on assess-ment of human health risks. The TARL is defined as thelevel of BTs in seafood that is tolerable by an averageconsumer with an average body weight of 60 kg and iscalculated based on the tolerable daily intake (TDI)(Belfroid et al., 2000). A TDI of 0.25 mg/kg bw/day forTBT was derived by Penninks (1993) based on theobserved effects of TBT on the immune function in ratsthat was extrapolated from rats to human in order tocalculate TARL (Belfroid et al., 2000). A same value ofTDI for DBT may also be assumed because it may havecomparable effect as those of TBT (Belfroid et al., 2000).This approach has been applied elsewhere to assess therisk to human health (Belfroid et al., 2000; Hong et al.,2001, Sudaryanto et al., 2002).

The average daily fish consumption per person inMalaysia is 146.9 g (FAO, 1998). Based on this informa-tion, the estimated dietary intake of butyltin (total BTs)in this country is in the range 1041e14,660 ng per personper day. This level is highest among dietary intake ofbutyltins in Asian and Oceanian countries, comparablewith those in Canada however, lower than in Japan andUSA (see Kannan et al., 1995). TARL of TBT forMalaysia is as high as 102 ng/g wet wt. (Belfroid et al.,2000). The species double spotted queenfish was noted tohave a TBT concentration of 190 ng/g wet wt. exceedingthe TARL in this country. Furthermore, several speciesalso had a concentration close to the level of TARL.Moreover, as previously reported for mussels, 5 out of 18locations also had concentration of TBT (110e730 ng/gwet wt.) exceeding TARL (Sudaryanto et al., 2002).Thus, based on these data, contamination levels of BTsin Malaysia, particularly from several polluted areas,may be of concern with regard to human health.

3.6. Anthropogenic sources

In order to elucidate the anthropogenic input oforganotins, the relationship between total BTs and totalSn (organicCinorganic tin) in fish and mussel (Sudar-yanto et al., 2002) were plotted in a graph (Fig. 5). Asignificant positive correlation was found between totalBTs and total Sn both in mussels and fish (Spearmanrank correlation: r2=0.82, P!0.0001). A similar result

has been found in several aquatic organisms from RiverElbe and the German coast of North Sea (Shawky andEmons, 1998) and those in marine mammals collectedaround Japanese waters (Le et al., 1999; Takahashi et al.,2000). Fig. 5 also shows that concentration ratios of BTsand total Sn in fish and mussels are approximately in therange of 1:1 and 1:10 depending up on sampling location.Mussels taken from an area adjacent to high maritimeactivities tend to have a ratio closer to 1:1 (Sudaryantoet al., 2002). A similar ratio was also observed in the fishcollected from the narrowest Strait of Malacca, whichhas been recognized as a heavy shipping traffic line. Thisindicates that anthropogenic sources of BTs influence thetotal tin accumulation. The individual with higher totalSn tends to have higher total BTs levels. However, heremussels seem to have ratio more close to 1:1 than the fish.This may be due to the fact that mussels inhabit coastalareas and hence receives more BTs from sources than fishwhich are in more open waters. The higher metaboliccapacity in fish than the mussel to degrade BTs mightalso be a possible explanation.

The percentage of BTs to total Sn both in mussels andfish varied widely (Fig. 6). Mussels collected fromLangkawi (an urban area and area of intensive maricul-ture), Penang Bridge (MYPEPB-2), Johore (MYJRTK)and Johore Bahru (thickly populated urban area witha port and many industries) showed high proportion ofBTs to total Sn. Moreover, fish collected from PortDickson and Parit Jawa ( fish caught from the nearestcoastal waters in Strait of Malacca) accumulated BTs,higher than fish collected from the northern Peninsularwaters. Areas which have heavier industrial, high boat-ing and intensive aquaculture activities showed highproportion of total BTs to total Sn, indicating significant

Fig. 5. Relationship betweenP

BTs andP

Sn in mussel and fish from

coastal waters of Malaysia.

356 A. Sudaryanto et al. / Environmental Pollution 130 (2004) 347e358

input of tin from anthropogenic origin of BTs such asantifouling paints and industrial usage. Tin in marineenvironment may result from both natural and anthro-pogenic sources. The tin compounds include bothorganic tin such as butyltin, phenyltin, octyltin, methyl-tin, etc.; and inorganic form. A part of methyltin mighthave been produced by the microbial methylation of in-organic tin; but most of the organic tin are of anthro-pogenic origin. Le et al. (1999) suggested that organic tinhave higher bioavailability than inorganic tin, thus view-ing from the tin composition (Fig. 6), the actual anthro-pogenic portion of tin to total tin compounds would begreater than those estimated only from BTs derivatives.In addition, several locations showed relatively higherproportion of other tin compounds than those of BTs,implying the presence of other sources of tin compoundsin several locations in Malaysia. It has been documentedthat other organotin compounds, such as phenyl, octyl,and methyltin compounds were present in aquatic eco-systems (Fent, 1996; Shawky and Emons, 1998).

4. Conclusions

Contamination by BTs is widely distributed alongcoastal waters of Malaysia and has been accumulated invarious environmental media and aquatic biota. Al-though, all locations showed the occurrence of BTs,several hot spots were observed particularly in areasadjacent to busiest port and ship traffic lines, suggestingthe areas of high maritime activities as main sources forthese contaminants. As the contamination level was thehighest in Asian developing countries and comparablewith those in some developed nations; the present status,usage and recent input into the marine environmenttogether with lack of regulation on their usage mayimpose serious pollution threat in the future. Probableoccurrence of other anthropogenic tin compounds,particularly which are known endocrine mimics causesfurther concern pointing towards the need of continuousstudy on the aquatic biota from Malaysian coastalenvironment.

Fig. 6. Proportion ofP

BTs inP

Sn in mussel and fish from coastal waters of Malaysia.

357A. Sudaryanto et al. / Environmental Pollution 130 (2004) 347e358

Acknowledgements

We are grateful to staff of Faculty of Science andEnvironmental Studies, University Putra Malaya, Ma-laysia for the collection of sediment, mussel, and fishsamples. We also thank Dr. An. Subramanian fromEhime University, Japan for the critical reading of thismanuscript. This research was supported by grants fromResearch Revolution 2002 (RR 2002) Project forSustainable Coexistence of Human, Nature and theEarth (FY 2002) and ‘‘21st Century COE Program’’from the Japanese Ministry of Education, Science,Sports, Culture, and Technology.

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