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Contamination by Brominated Flame Retardants in Soil Samplesfrom Open Dumping Sites of Asian Developing Countries

Akifumi EGUCHI1, Tomohiko ISOBE1, Annamalai SUBRAMANIAN1,Agus SUDARYANTO1, Karri RAMU1, Tu Binh MINH2,

Paromita CHAKRABORTY3, Nguyen Hung MINH4, Touch Seang TANA5,Pham Hung VIET2, Shin TAKAHASHI1 and Shinsuke TANABE1

1Center for Marine Environmental Studies (CMES), Ehime University,Bunkyo-cho 2-5, Matsuyama 790-8577, Japan

2Department of Biology and Chemistry, City University of Hong Kong, China3State Key Laboratory of Organic Geochemistry Guangzhou Institute

of Geochemistry, China4Center for Environmental Technology and Sustainable Development (CETASD), Vietnam

5Social and Cultural Observation Unit (OBSES) of the Cabinet of the Council ofMinisters, Phnom Penh, Cambodia

(Received 26 January 2009; accepted 11 March 2009)

Abstract—Brominated flame retardants have been widely used in homes,workplaces and subsequently, they have become widely dispersed in theenvironment. The garbage containing them is dumped in refuse dumping sites,and causes pollution. But data on their environmental concentrations arescarce. The purpose of this study is to elucidate their status of pollution in Asiandeveloping countries’ refuse dumping sites. The soil samples collected fromthose areas were analyzed for the concentrations of PBDE and HBCD.Concentrations of mono-deca BDE were 0.5–410 ng/g dry wt. and HBCD wereN.D–2.4 ng/g dry wt. From our results, we found that PBDE contamination hasspread in various parts of Asia but HBCD has not spread so much at present.Further studies are needed for continuous monitoring of the problems such asinflow of waste from developed countries.

Keywords: brominated flame retardants (BFRs), polybrominated diphenylethers (PBDEs), hexabromocyclododecanes (HBCDs), tetrabromobisphenol A(TBBPA), electronic-waste (e-waste)

INTRODUCTION

Brominated flame retardnats (BFR) are used in many consumer products such asplastics, textiles, electronic equipment and furniture to prevent fire. Mostly usedBFRs are polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes(HBCDs), and tetrabromobisphenol A (TBBPA). Widespread use, high chemicalstability, high lipophilicity and bioaccumulation potential of some PBDEs haveled to increasing contamination of the environment, wildlife, and human (Hites,

Interdisciplinary Studies on Environmental Chemistry — Environmental Research in Asia,Eds., Y. Obayashi, T. Isobe, A. Subramanian, S. Suzuki and S. Tanabe, pp. 143–151.© by TERRAPUB, 2009.

144 A. EGUCHI et al.

2004; Law et al., 2005; Covaci et al., 2006). Brominated diphenyl ethers cancause adverse physiological effects, both in vitro and in vivo, including endocrinedisruption and interference with neurobehavioral development (Darnerud, 2003;Birnbaum and Staskal, 2004). Toxicity of HBCD is lower than PBDE (Birnbaumand Staskal, 2004). However, it is reported that HBCD might have harmful effectson nerves (Mariussen and Fonnum, 2003). In 2001, the global productions of thetechnical PBDE mixtures, Penta-, Octa- and Deca-BDEs, were 8500, 1375 and8290 tons, respectively. For HBCD, the global demand was 15900 tons in 1999(BSEF, 2003). In Asia, production of BFRs, Penta-, Octa-, Deca-BDEs, andHBCDs were 150, 2000, 23000, 3900 tons, respectively. Among these, theconsumption of Penta-, Octa- and Deca-BDEs and HBCD in Japan accounted for0, 0, 10, and 56%, respectively (Watanabe and Sakai, 2003). Except for HBCD,other BFRs may be in extensive use in Asian developing countries. Penta- andOcta-BDE products were banned in 2004 by the European Union (EU) as well asby the states of Maine, Hawaii, Michigan, Washington, Oregon, Illinois, Maryland,and New York in USA. Following the ban of these two products, Deca-BDE hasreceived much interest, since it remains the only diphenyl-ether-based brominatedflame retardant available (Kemmlein et al., 2009). The EU risk assessment reportfor technical Deca-BDE states that there is a high level of uncertainty associatedwith the suitability of the current risk assessment approach on secondary poisoningand the debromination issue. Moreover, in recent years, there are about 50 milliontons of Electronic-waste (e-waste) produced annually in the world and are alsotransported in massive quantities to developing countries. During the cruderecycling of e-waste, PBDEs may be emitted into the environment. In the researchconducted in Guiyu, China, high levels of dioxin and bromine have been detected(Leung et al., 2007). It was thought that garbage containing BFRs are discarded

Fig. 1. Map showing the sampling locations of soils.

Brominated Flame Retardants in Soil Samples from Open Dumping Sites 145

to dumping sites of many cities. Therefore, health risk is feared for residentsaround waste dumping sites. However, the report concerning the soil contaminationby BFRs is few. There is especially no research that pays attention to themunicipal waste dumping sites. This study pays attention to the municipal wastedumping sites, and the pollution by BFRs from such sites in developing Asiancountries.

MATERIALS AND METHODS

Sample collection

Soils were sampled at 32 stations from the control and dumping site areas inIndia, Vietnam, Malaysia, Indonesia, and Cambodia during 1999–2004 (Fig. 1).The samples were transported to Environmental Specimen Bank for GlobalMonitoring (ES-BANK) at Ehime University under frozen condition. Soil sampleswere screened by 2 mm sieve, air dried, packed in polyethylene bags and frozenat –20°C until chemical analysis.

Chemical analysis

Analysis of PBDEs was performed following the procedure described byUeno et al. (Ueno et al., 2004) with slight modification. Briefly, 5 g of the soilsample was Air dried. Extraction of soil was carried out by Hexane:Acetone(50:50 v:v 50 mL, 15 min) using electric shaker (SR-2W model, TAITEC, Japan)and two times in ultrasonic bath (Tokyo Rikakikai, Japan). This extractionprocedure was repeated once using fresh solvent. An aliquot of the extract, afterspiking 5 ng of internal standards for PBDEs (13C12-labeled BDE-3, BDE-15,BDE-28, BDE-47, BDE-99, BDE-153, BDE-154, BDE-183, BDE-197, BDE-207and BDE-209) and 10 ng of internal standards for HBCDs (13C12-labeled α-, β-and γ-HBCD) was passed through multilayer silica gel column. After acidtreatment, the solution was added to a gel permeation chromatography column(GPC) for lipid removal. The GPC fraction containing organohalogens wasconcentrated and passed through 4 g of activated silica gel (Wakogel DX, WakoPure Chemical Industries Ltd., Japan) column. The first fraction eluted with 5%dichloromethane in hexane contained PBDEs, while the second fraction elutedwith 25% dichloromethane in hexane contained HBCDs. To remove sulfur, theactivated copper was used in the PBDE fraction. 13C12-labled BDE-139 wasadded to the final solution prior to GC-MS analysis for PBDEs. Quantificationwas performed using a GC (Agilent 6890N) equipped with MS (Agilent 5973N)for mono- to hepta-BDEs, and GC coupled with MS (JEOL GCmate II) for octa-to deca-BDEs, using electron ionization with selective ion monitoring (EI-SIM)mode. GC columns used for quantification were DB-1MS fused silica capillary(J&W Scientific Inc.) having 30 m × 0.25 mm i.d. and with 0.25 mm filmthickness for mono- to hepta-BDEs, and 15 m × 0.25 mm i.d. and with 0.1 mm filmthickness for octa- to deca-BDEs. Fourteen major congeners of PBDEs (BDE-3,BDE-15, BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183,

146 A. EGUCHI et al.

BDE-196, BDE-197, BDE-206, BDE-207 and BDE-209) were quantified in thisstudy. All the congeners were quantified using the isotope dilution method to thecorresponding 13C12-labeled congener. Recovery of 13C12-labeled BDE rangedbetween 60% and 120%. The fraction containing HBCDs was solvent exchangedinto methanol and 10 ng of d18-labeled α-, β- and γ-HBCD was added to the finalsolution prior to liquid chromatography combined with tandem mass spectrometry(LC-MS-MS) analysis, as a performance standard. The diastereomeric analysisof HBCDs was performed on the basis of an analytical method reported previously(Tomy et al., 2004). Samples were analyzed with Quattro Micro APItriplequadrupole mass spectrometer (Waters/Micromass, Tokyo, Japan) equippedwith Alliance 2795 LC separation module (Waters, Tokyo, Japan). Separation ofHBCD isomers (α-, β- and γ-) was achieved with an Extend-C18 column (2.1 mmi.d. × 150 mm, 5 mm particle size). The mobile phase consisted of water/acetonitrile/methanol (20:30:50) at 200 ml/min in initial condition for 2 min andthen ramped to acetonitrile/methanol (30:70) for 5 min, and kept for 6 min. TheMS-MS analysis, which was operated in negative mode of electrospray ionization(ESI), was performed in multiple reaction monitoring mode (MRM). Quantificationof native HBCDs was achieved from the mean value of the response of two MRMtransitions (i.e., m/z 640 > 81, m/z 642 > 81) corrected with response of 13C12-HBCDs (i.e., m/z 652 > 81 MRM transition). HBCD isomers were quantified byisotope dilution using the corresponding 13C12-labeled isomers. Recoveries of13C12-labeled HBCD during analytical procedure were determined using d18-labeled isomers and the values ranged between 50% and 120%. The relativestandard deviation (RSD) of four samples was less than 5%. Method detectionlimits (MDLs) were determined using spiked blank (13C12-labeled isomers)samples (n = 3). MDLs were calculated as three times standard deviation of

Control site Near Dumping site Dumping site

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102

Can Tho(Vietnam)

Kolkata(India)

Phnom Penh(Cambodia)

Bogor(Indonesia)

Kuala Lumpur(Malaysia)

Chennai(India)

Fig. 2. Concentration of PBDEs in soil samples from Asian countries (ng/g dry wt.).

Brominated Flame Retardants in Soil Samples from Open Dumping Sites 147

background peaks in the blanks. MDLs of α-HBCD, β-HBCD and γ-HBCD were0.01, 0.01 and 0.01 ng/g dry weight (based on 5 g of sample), respectively.

RESULTS AND DISCUSSIONS

PBDEs

PBDEs were detected in all the samples analyzed in this study. Mean andtotal PBDE concentrations are presented in Figs. 2 and 6, respectively. Thehighest mean values were found in Vietnam, followed by Cambodia, India,Indonesia and Malaysia. The highest PBDE concentration was detected in thedumping site at Hanoi, Vietnam. PBDE concentrations were higher in dumpingsites than the respective control sites even though the differences were notsignificant. This may indicate that the dumping sites in the suburbs of the majorcities of developing countries are the sources of PBDE contamination. The levelsof the PBDEs at the dumping sites of the present study are almost equal to thosefound in United States and Europe (Offenberg et al., 2006; Leung et al., 2007).However, the values in the present study were not high as those observed in theE-waste processing region in China. In this study a total of 14 congeners frommono- to deca-BDEs were identified in soils from Asian dumping sites. BDE-209is dominant in most of the samples (Fig. 4). The reasons for such a pattern maybe the fact that the Asian developing countries are using plenty of Deca-BDEcontaining mostly BDE-209 which has a strong binding capacity to soil. But insome places, low brominated BDEs were also detected. The detection of lowbrominated BDE could be due to the use of penta-BDE (La et al., 2006) and thephotolytic and thermal debromination of the higher brominated congeners,especially BDE-209 (Soderstrom et al., 2004).

Control site Near Dumping site Dumping site

Can Tho(Vietnam)

Kolkata(India)

Phnom Penh(Cambodia)

Bogor(Indonesia)

Kuala Lumpur(Malaysia)

Chennai(India)

HB

CD

Con

cent

rati

on (

ng/g

dry

wt.

)

10–2

10–1

100

101

Fig. 3. Concentration of HBCDs in soil samples from Asian countries (ng/g dry wt.).

148 A. EGUCHI et al.

HBCDs

HBCDs were detected in 29 samples analyzed in this study. The average totalHBCDs concentrations are presented in Figs. 3 and 6. Comparing the averagevalues of different countries showed the highest values in India, followed byVietnam, Cambodia, Indonesia and Malaysia. As for the HBCDs, higher valueswere found in the dumping site than the control site even though the differenceswere insignificant. HBCDs concentration in this study is lower than the UnitedStates and Europe (Remberger et al., 2004; Malte et al., 2004). Concentration ofHBCD is low because the amount of the HBCD use in Asia is lower than indeveloped nations. Among the HBCDs isomers detected γ-HBCD was usuallypredominant (Fig. 5). Technical HBCD product is contains three diastereomers(α-, β- and γ-) with γ-HBCD contributing approximately 80% of technicalformulation (Alaee, 2003). γ-HBCD has a strong binding affinity to soil. But insome places, α-HBCD was predominant. In the open dumping sites, heat generatedby open burning and autogenous ignition may change the isomeric compositionof technical HBCD mixture at temperatures above 160°C, leading to conversionof γ- to <-HBCD (Barontini et al., 2001). Depending on the temperature of thetreatment processes, the proportions of the isomers in the end product may alsovary (Tomy et al., 2004). Moreover, the water solubility of α-HBCD is higherthan that of the γ-HBCD; the particle absorbance of the α-HBCD is weaker thanthat of the γ-HBCD and hence α-HBCD was found to move easily betweendifferent environmental matrices.

Fig. 4 . PBDE profiles in soil samples from Asian countries. The mixture queues up from the left inorder of DE-71 (Penta-mixture), 70-5DE (Penta-mixture), DE-79 (Octa-mixture), 79-8DE(Octa-mixture), Saytex-102E (Deca-mixture) and 82-0DE (Deca-mixture) (La et al., 2006).

Brominated Flame Retardants in Soil Samples from Open Dumping Sites 149

Fig. 6. Global Comparison of BFRs concentrations in soils (ng/g dry wt.).

Fig. 5. HBCD profiles in soil samples from Asian countries. The mixture queues up from the leftin order of two HBCD technical mixtures and heat treated HBCD mixture (Barontini et al., 2001;Covaci et al., 2006).

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Am

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102

103

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Leung et al., 2007: Offenberg et al., 2006: Malte et al., 2004

CONCLUSIONS

Concentrations of mono-deca BDE found in the soils of Asian developingcountries were from 0.47 to 410 ng/g dry wt., and HBCD were from N.D to 2.4ng/g dry wt. The levels of these compounds in the dumping site soils were higherthan the levels in the respective control sites. Dumping sites in the suburbs ofmajor cities in Asian developing countries were found to be possible sources ofPBDEs contamination. PBDEs concentration from dumping sites of the present

150 A. EGUCHI et al.

study was more or less the same as in the United States and Europe. As a result,it became clear that contamination of PBDEs has become widespread in variousparts of Asia. On the other hand, contamination of HBCDs is not wide spread asPBDEs, at present. Future continuous monitoring is needed in developingcountries to monitor problems, such as inflow of e-waste from developed nations.

Acknowledgments—This study was supported by “Global COE Program”, Grants-in-Aidfor Scientific Research (S) (No. 20221003) from the Ministry of Education, Culture,Sports, Science and Technology, Japan (MEXT) and Japan Society for the Promotion ofScience (JSPS) and the Waste Management Research Grant (K2062) from the Ministry ofEnvironment, Japan.

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