Selection of Bioindicators of Polybrominated Diphenyl Ethers, Polychlorinated Biphenyls, and Organochlorine Pesticides in Mollusks in the Chinese Bohai Sea YAWEI WANG, † THANH WANG, † AN LI, ‡ JIANJIE FU, † PU WANG, † QINGHUA ZHANG, † AND GUIBIN JIANG* ,† State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, School of Public Health, University of Illinois at Chicago, Chicago, Ilinois Received April 16, 2008. Revised manuscript received July 3, 2008. Accepted July 7, 2008. Mollusks, including bivalve and gastropod samples, were collected in the summer of 2006 and 2007 to evaluate the spatial patterns of organochlorine pesticides (OCPs), polychlorinated biphenyl (PCBs), and polybrominated biphenyl ethers (PBDEs) in the coastal water of the Chinese Bohai Sea. Seven species of mollusks, including Rapana venosa (Rap), Neverita didyma (Nev), Scapharca subcrenata (Sca), Mytilus edulis (Blue mussel, Myt), Amusium (Amu), Meretix meretrix (Mer), and Crassostrea talienwhanensis (Oyster, Ost) were investigated to select appropriate bioindicators. Compared with other species, Ost and Myt possess higher lipid contents and have higher concentrations of OCPs and PBDEs. Multivariate linear regression analysis revealed that the most influential factor on the contaminant concentrations in mollusks is the trophic level (TL), followed by the lipid contents. Concentrations of OCPs, PCBs, and PBDEs correlated negatively with the TL of the selected mollusks. Results of principal component and correlation analyses suggest that Ost and Myt can be used as potential bioindicators of pollution by OCPs, PCBs, and PBDEs of the Chinese Bohai Sea. Introduction Persistent organic pollutants (POPs) are of great environ- mental and health concern. Several organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) have been targeted for restriction or ultimate elimination by the Stockholm Convention on POPs which went into effect in 2004. Other groups of organic contaminants, including polybrominated diphenyl ethers (PBDEs), are considered the next generation of POPs to be included into the treaty due to their similarities to the banned chemicals in regard to health effects as well as their ubiquitous presence in the environment (1). OCPs were widely used in China from the 1950s to the 1980s. Although the usage of OCPs was banned in 1983, evidence shows that some OCPs, such as lindane (γ-HCH), are still being used in the country (2). An estimated 10 000 tons of PCBs were manufactured in China between 1965 and 1974 and were used primarily as an additive in paint and as a dielectric fluid in transformers (3). PBDEs have been found to severely contaminate several coastal areas of China, which is mainly attributed to the electronic waste import and dismantling and the manufacturing of decabromodiphenyl ether (1, 3). To elucidate the distribution of POPs on global and regional scales, aquatic or marine organisms have been used as bioindicators (4-6). Different from other species (e.g., skipjack tuna and snapping turtles) used previously (5, 6), mollusks have unique characteristics. As water-respiring filter feeder species with a sessile lifestyle, their elimination of persistent pollutants with Kow > 10 5 is sufficiently slow, which causes bioaccumulation of these chemicals (7). Mollusks including bivalves and gastropods have long been used as potential bioindicators and biomonitors, (e.g. in the Mussel Watch program (8)) for their high accumulation capacity and abundance in marine ecosystems. In the Asia-Pacific mussel watch program, Tanabe and co-workers (9-11) assessed contamination by various POPs using mussels in the coastal waters of Asian countries, including China, India, Japan, Korea, and more. The Bohai Sea of China is surrounded by four provinces, with a number of large cities near its shoreline. Historically over nearly four decades, large amounts of OCPs were manufactured and applied for agricultural use in the region. With about one-sixth of the total population and a quarter of the total GDP of China, the Bohai Bay Rim economic zone has now become a hot spot for investment. However, the rapid socioeconomic growth has raised concerns about the potential deterioration of the Bohai ecosystem. This work is a comprehensive investigation of OCPs, PCBs, and PBDEs in mollusks collected from coastal water of the Chinese Bohai Sea in 2006 and 2007. The objectives are to select the most suitable mollusk species as bioindicators and to examine the temporal trend and spatial distributions of these pollutants in the area. Experimental Section Sampling. Mollusks were collected from nine coastal cities along the Bohai Sea, including Dalian (DL), Yingkou (YingK), Huludao (HLD), Qinhuangdao (QHD), Tianjin (TJ), Yangkou (YangK), Penglai (PL), Yantai (YT), and Weihai (WH). A map showing sampling locations is given in the Supporting Information (Figure S1). The sampling was carried out in late July to early August of 2006 and 2007. A total of 114 samples (59 in 2006 and 55 in 2007) were collected. Seven species of mollusks, including Rapana venosa (Rap), Neverita didyma (Nev), Scapharca subcrenata (Sca), Mytilus edulis (Myt), Amusium (Amu), Meretix meretrix (Mer), and Crassostrea talienwhanensis (Oyster, Ost) were identified (Table S1) (12). Detailed sample collection and transportation procedures have been de- scribed previously (13, 14). Sample Analysis. Sample pretreatment, instrumental analysis, quality assurance and quality control, and quan- tification of the data followed our previously established methods (13, 14), with minor modifications, and are described in detail in the Supporting Information. OCPs, including hexachlorobenzene (HCB); R-, -, γ-, and δ-hexachlorocy- clohexanes (HCH); o,p′-DDE; p,p′ -DDE; o,p′-DDD; p,p′ -DDD; o,p′-DDT; and p,p′-DDT, were analyzed using Agilent 6890A gas chromatography equipped with a 63 Ni electron * Corresponding author phone: 8610-6284-9334; fax: 8610-6284- 9179; e-mail: gbjiang@rcees.ac.cn. † Chinese Academy of Sciences. ‡ University of Illinois at Chicago. Environ. Sci. Technol. 2008, 42, 7159–7165 10.1021/es801058u CCC: $40.75  2008 American Chemical Society VOL. 42, NO. 19, 2008 / ENVIRONMENTAL SCIENCE & TECHNOLOGY 9 7159 Published on Web 08/22/2008