Environ. Sci. Technol. 2007, 41, 4580-4586
Asian Mussel Watch Program: Contamination Status of Polybrominated Diphenyl Ethers and Organochlorines in Coastal Waters of Asian Countries
in mussels from Hong Kong, Vietnam, and China; PCBs were found in Japan, Hong Kong, and industrialized/urbanized locations in Korea, Indonesia, the Philippines, and India; CHLs were found in Japan and Hong Kong; HCHs were found in India and China. These countries seem to play a role as probable emission sources of corresponding contaminants in Asia and, in turn, may influence their global distribution.
KARRI RAMU,† NATSUKO KAJIWARA,† AGUS SUDARYANTO,† TOMOHIKO ISOBE,† SHIN TAKAHASHI,† ANNAMALAI SUBRAMANIAN,† DAISUKE UENO,‡ GENE J. ZHENG,| PAUL K. S. LAM,| HIDESHIGE TAKADA,⊥ MOHAMAD PAUZI ZAKARIA,X PHAM HUNG VIET,§ MARICAR PRUDENTE,¶ TOUCH SEANG TANA,# AND S H I N S U K E T A N A B E * ,† Center for Marine Environmental Studies, Ehime University, Bunkyo-cho 2-5, Matsuyama 790-8577, Japan, Division of Environmental Conservation, Saga University, Japan, Department of Biology and Chemistry, City University of Hong Kong, HKSAR, China, Laboratory of Organic Geochemistry, Tokyo University of Agriculture and Technology, Japan, Faculty of Environmental Studies, Universiti Putra Malaysia, Malaysia, Center for Environmental Technology and Sustainable Development, Hanoi National University, Vietnam, Science Education Department, De La Sella University, Philippines, and Social and Cultural Observation Unit (OBSES), Office of the Council of Ministers, Cambodia
Introduction
Mussel samples were used in this study to measure the levels of polybrominated diphenyl ethers (PBDEs) and organochlorines (OCs) in the coastal waters of Asian countries like Cambodia, China, Hong Kong, India, Indonesia, Japan, Korea, Malaysia, the Philippines, and Vietnam. PBDEs were detected in all the samples analyzed, and the concentrations ranged from 0.66 to 440 ng/g lipid wt. Apparently higher concentrations of PBDEs were found in mussels from the coastal waters of Korea, Hong Kong, China, and the Philippines, which suggests that significant sources of these chemicals exist in and around this region. With regard to the composition of PBDE congeners, BDE-47, BDE-99, and BDE-100 were the dominant congeners in most of the samples. Among the OCs analyzed, concentrations of DDTs were the highest followed by PCBs > CHLs > HCHs > HCB. Total concentrations of DDTs, PCBs, CHLs, and HCHs in mussel samples ranged from 21 to 58 000, 3.8 to 2000, 0.93 to 900, and 0.90 to 230 ng/g lipid wt., respectively. High levels of DDTs were found * Corresponding author phone: +81-89-927-8171; fax: +81-89927-8171; e-mail:
[email protected]. † Ehime University. ‡ Saga University. | City University of Hong Kong. ⊥ Tokyo University of Agriculture and Technology. X Universiti Putra Malaysia, Malaysia. § Hanoi National University. ¶ De La Sella University. # Office of the Council of Ministers, Cambodia. 4580
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Coupled with economic development, an escalation in agricultural and industrial activities in Asia has resulted in increased production and usage of various chemicals in this region. Among the organic contaminants of current interest and concern, recent evidence has confirmed that the brominated flame retardants (BFRs), like polybrominated diphenyl ethers (PBDEs), are ubiquitous environmental pollutants and are similar in physicochemical properties to a number of other persistent organic pollutants (POPs) (1). PBDEs have been commonly used in furniture (polyurethane foam), wire and cable insulation, electronics and computers (high impact polystyrene), etc. Over the past decade, several environmental monitoring programs have indicated increasing levels of several tetra- to deca-BDE isomers in sediments, bird eggs, marine mammals, and human tissues (1). Increasing concentrations of PBDEs in the environment have been attributed to several causes, including increased disposal of outdated electronic equipment (2) and volatile losses from products in use (3). Because of the widespread use of these compounds as flame retardants, there is a growing concern on monitoring the levels of PBDEs in different environmental compartments in order to determine their environmental impact. Studies on environmental behavior of PBDEs are chiefly derived from Europe and North America and there are only a few reports from Asia. As a result, there is an urgent need to identify sources of PBDEs in the Asian region. As for organochlorines (OCs), though most of the developed countries banned or restricted the production and usage of many OCs during the 1970s and the 1980s, these chemicals are still being used in some Asian developing nations for agricultural and public health purposes (4, 5). For instance, recent input of dichlorodiphenyl trichloroethanes (DDTs) and hexachlorocyclohexane isomers (HCHs) has been recorded in some Asian developing countries (6, 7). Thus, information on sources and emissions of organohalogen compounds into the environment of Asia is needed to understand regional sources of organohalogen compounds and the key processes that control their global distribution. Bivalves, especially mussels, are widely used as sentinel organisms for monitoring chemical contaminants in coastal and estuarine ecosystems because they, being filter feeders, bioaccumulate contaminants. This approach has become popularly known as the “Mussel Watch Program” and has been adopted in many countries to study environmental contaminant levels (6, 8-10). Our previous Asia-Pacific mussel watch program (APMWP) assessed contamination by OCs in coastal waters of Asian countries (6). In our recent study (11), we followed a similar approach to understand the contamination status of BFRs in mussels from coastal waters of Korea and found elevated levels of PBDEs and hexabromocyclododecanes (HBCDs). These data prompted us to expand our area of research to other Asian countries to determine the levels of PBDEs and OCs in mussels from Asian coastal waters. 10.1021/es070380p CCC: $37.00
2007 American Chemical Society Published on Web 05/24/2007
Materials and Methods Samples. Green mussels (Perna viridis) and blue mussels (Mytilus edulis) were collected from various locations in Cambodia, China, Hong Kong, India, Indonesia, Japan, Malaysia, the Philippines, and Vietnam from 2003 to 2005 (n ) 46). Results from our previous study (11) on mussels collected from Korea (n ) 22) are also included in the present study for comparison and further discussion. The details of the sampling locations are presented in Figure S1 and Table S1 of the Supporting Information. After shucking the whole soft tissues of mussels from each location, they were pooled, homogenized, and frozen at -20 °C until chemical analysis. Chemical Analysis. Analysis of PBDEs was performed following the procedure described by Ueno et al. (12) with slight modification. Briefly, 20-30 g of the homogenized mussel sample was ground with anhydrous sodium sulfate and extracted in a Soxhlet apparatus with a mixture of diethyl ether and hexane for 7-8 h. An aliquot of the extract, after adding 5 ng of internal standards (13C12-labeled BDE-3, BDE15, BDE-28, BDE-47, BDE-99, BDE-153, BDE-154, BDE-183, BDE-197, BDE-207, and BDE-209), was added to a gel permeation chromatography (GPC; Bio-Beads S-X3, Bio-Rad Laboratories, CA, 2 cm i.d. and 50 cm length) column for lipid removal. The GPC fraction containing organohalogens was concentrated and passed through 4 g of activated silica gel (Wakogel DX, Wako Pure Chemical Industries Ltd., Japan) column with 5% dichloromethane in hexane for clean up. 13C -labled BDE-139 was added to the final solution prior 12 to analysis with gas chromatograph equipped with a massselective detector (GC-MSD). Quantification was performed using a GC (Agilent 6890N) equipped with MSD (Agilent 5973N) for mono- to hepta-BDEs, and GC coupled with MS (JEOL GCmate II) for octa- to deca-BDE, having an electron impact with selective ion monitoring (EI-SIM) mode. GC columns used for quantification were DB-1 fused silica capillary (J&W Scientific Inc.) having 30 m × 0.25 mm i.d. × 0.25 µm film thickness for mono- to hepta-BDEs, and 15 m × 0.25 mm i.d. × 0.1 µm film thickness for octa- to decaBDE. Fourteen major congeners of PBDEs (BDE-3, BDE-15, BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE183, BDE-196, BDE-197, BDE-206, BDE-207, and BDE-209) were quantified in this study. All the congeners were quantified using the isotope dilution method to the corresponding 13C12-labeled congener. Recovery of 13C12-labeled BDEs ranged between 60 and 120%. OCs including polychlorinated biphenyls (PCBs), DDTs, HCHs, chlordane related compounds (CHLs), and hexachlorobenzene (HCB) were analyzed following the method described by Kajiwara et al. (13). Another aliquot of the extract was subjected to GPC for lipid removal. The GPC fraction containing OCs was concentrated and passed through an activated Florisil column for cleanup and fractionation. Quantification of PCBs and most of the organochlorine pesticides was performed using a GC equipped with a micro electron capture detector (micro-ECD) and an auto-injection system (Agilent 7683 Series Injector). The GC column used for OC analysis was a fused silica capillary (DB-1; 30 m × 0.25 mm i.d. × 0.25 µm film thickness, J&W Scientific Inc.). The concentration of individual OCs was quantified from the peak area of the sample to that of the corresponding external standard. The PCB standard used for quantification was a mixture of 62 PCB isomers and congeners (BP-MS) obtained from Wellington Laboratories Inc., Ontario, Canada. Concentrations of individually resolved peaks of PCB isomers and congeners were summed to obtain total PCB concentrations. Procedural blanks were analyzed simultaneously with every batch of five samples to check for interferences or contamination from solvents and glassware. Lipid contents
were determined by measuring the total nonvolatile solvent-extractable material on subsamples taken from the original extracts. For quality assurance and control, our laboratory participated in the Intercomparison Exercise for Persistent Organochlorine Contaminants in Marine Mammals Blubber, organized by the National Institute of Standards and Technology (Gaithersburg, MD) and the Marine Mammal Health and Stranding Response Program of the National Oceanic and Atmospheric Administration’s National Marine Fisheries Service (Silver Spring, MD). Standard reference material (SRM 1945) was analyzed for selected PCB congeners and persistent OCs. Data from our laboratory were in good agreement with those for reference materials. The average percentage deviation from the certified values were 13% (range: 0.5-20%) for organochlorine pesticides and 28% (range: 1.3-57%) for PCB congeners.
Results and Discussion Contamination Status of PBDEs. PBDE concentrations detected in the soft tissue homogenates of mussel samples from coastal waters of Asia are shown in Table 1 and Figure 1. PBDEs were detected in all the mussel samples analyzed indicating widespread contamination by these compounds in the coastal waters of Asia. Contamination status of PBDEs in mussels varied depending on countries and the local sites of sampling. The sum concentrations of all PBDE congeners (mono- to deca-BDE) ranged from 0.66 to 440 ng/g lipid wt., with apparently higher levels in mussel samples from Korea, the Philippines, Hong Kong, and China. Lower residue levels of PBDEs were detected in samples from Cambodia, Vietnam, India, and Malaysia. Of the 14 congeners analyzed, a total of 13 congeners from di- to deca-BDE were identified. BDE-3 (mono-BDE) was not found above the detection limit of 0.1 ng/g lipid wt. in all the samples. BDE-47, BDE-99, and BDE-100 were the dominant congeners, and BDE-47 was found to be the predominant congener in most of the locations in the present study (see Table S2 and Figure S2, Supporting Information), an observation that is consistent with results from other investigations (14, 15). However, mussels from China showed higher contribution of BDE-209 to total concentrations of PBDEs. Despite the differences in total PBDE levels, it appears that in environmental samples, tetra- and penta-congeners are prevalent on a worldwide basis. It has been suggested that major congeners of pentaBDE commercial mixture (BDE47, BDE-99, and BDE-100) might be more available for dispersion in the environment because of their use as flame retardants in products such as polyurethane foams, which are prone to easy degradation and disintegration (16). The degradation of higher brominated congeners to lower brominated ones might also contribute to the higher proportion of lower brominated BDEs in biological samples (17). The major congener in decaBDE formulation, BDE-209, was detected in mussel samples from China, Korea, Hong Kong, Japan, and Indonesia at varying levels. The relative PBDE congener patterns in mussels from different geographical locations may differ mainly due to differences in sources and pathways. In China, decaBDE is one of the largely produced flame retardants and high levels of BDE-209 were detected in the riverine and coastal sediments of South China (18). Moon et al. (19) reported that in Korea, decaBDE accounted for 25% of the total BFR consumption of 49 050 tons in the year 2002. Higher brominated congeners have high log Kow, thus, they are primarily bound to particulate organic carbon. Mussels, as filter feeders, accumulate these contaminants from suspended particulate matter, which is an important carrier for higher brominated BDEs in the aquatic environment (20). Since the mussels in the present study were not depurated before being shucked, detection VOL. 41, NO. 13, 2007 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
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TABLE 1. Concentrations of Organohalogen Compounds (ng/g Lipid wt.) in Mussels from Coastal Waters of Asia locations
Cambodia Preab Island Koh Kchorng China Xiamen (Haichang) Qingzhou Fuzhou (Ming Jian) Beihai Shantau (Lauping) Cheng Si Dao Dalian Chong Ming Dao, Shanghai Lian Yun Gang Jiao Zhou Wan, Qingdao Hong Kong Tsim Sha Tsui Kat O Cheung Chau Sai Wan Ho Ma Liu Shui Lung Kwu Tan Ma Wan Ma On Shan Sha Tau Kok Lamma Island India Pondicherry Kakinada Kasimidu Jetty Indonesia Jakarta Bay, Muara Angek A Jakarta Bay, Muara Angek B Jakarta Bay, Cilincing A Jakarta Bay, Cilincing B Japan Osaka Hokkaido Fukui Mie Miyagi Koreac Uljin A Ganggu, Yandok M-3 Yeongil Bay, Pohang M-2 Guryongpo Welseong B Ulsan Bay, M-8 Ulsan Bay, M-6 Onsan Bay, M-1 Onsan Bay, M-2 Kori, Ulju County A Busan Bay, M-1 Wonmunnpo, M-1 Kohyonsong Bay, Geoje M-3 Okpo Bay, M-2 Masan Bay, M-2 Haengam Bay, Jinhae Gwangyang Bay Gamak Bay, Yeosu Sacheon Bay, Sacheon Shihwa Lake, Incheon Garorim Bay, Dangjin Chunsu Bay, Hongseong Malaysia Port Dickson Pantai Lido, Johor Bahru Pasir Puteh Sebatu Penang Philippines Bacoor, Cavite Naic, Cavite 4582
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lipid (%)
PBDEs
PCBs
CHLs
HCHs
120 120
4.1 2.5
5.5 7.2
40000 8300 1800 11000 26000 1500 480 13000 570 10000
220 27 39 77 170 39 10 62 4.9 65
36 14 20 24 43 24 43 96 21 79
