Occurrence and distribution of organochlorine pesticides (OCPs) in surface sediments of the Bohai Sea, China Limin Hu a,b , Gan Zhang c,d , Binhui Zheng e , Yanwen Qin e , Tian Lin d , Zhigang Guo a,b, * a Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China b Key Laboratory of Submarine Geosciences and Prospecting Techniques, Ministry of Education of China, College of Marine Geosciences, Ocean University of China, Qingdao 266100, China c Yantai Institute of Coastal Zone Research for Sustainable Development, Chinese Academy of Sciences, Yantai 264003, China d State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China e Water Research Institute, Chinese Research Academy of Environmental Sciences, Beijing 100012, China article info Article history: Received 1 February 2009 Received in revised form 12 July 2009 Accepted 28 July 2009 Available online 25 August 2009 Keywords: Organochlorine pesticides Surface sediments Principal component analysis Biological risks The Bohai Sea abstract Fifty-five surface sediment samples covering virtually the entire Bohai Sea (Bohai) were analyzed for organochlorine pesticides (OCPs), in order to provide the extensive information of recent occurrence lev- els, distribution, possible sources and potential biological risk of these compounds in this area. Concen- trations of total dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs) in Bohai ranged widely from 0.24 to 5.67 ng g À1 (mean 1.36 ± 0.93 ng g À1 ) and 0.16 to 3.17 ng g À1 (mean 0.83 ± 0.57 ng g À1 ), respectively. High concentrations of DDTs were observed in the coastal areas espe- cially at the isolated sites neighboring the harbor or port regions. The recent DDT inputs could be mainly attributed to the agricultural activity (e.g. dicofol), wastewater of chemical plants and the usage of anti- fouling paint. The distribution pattern of HCHs was different from that of DDTs due to their different physical–chemical properties and amounts of production and usage in the past. (DDE + DDD)/DDT ratios indicated that the degradation of the parent DDT occurred significantly. The contributions of previous and current inputs of pesticides in the coastal areas were distinguished by means of principal component analysis, suggesting that the recent usage of DDT and technical chlordane could serve as important fresh input sources for OCPs. DDTs and chlordanes are the two-main species of OCPs with more ecotoxicolog- ical concern in Bohai. Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction Organochlorine pesticides (OCPs), one of the persistent organic pollutants (POPs) groups, are ubiquitous in the environmental ma- trixes. OCPs were widely used in the world from the 1950s. There has been an extensive concern for OCPs due to their high toxicity, persistence, bioaccumulation and biomagnification in the environ- ment (Zhang et al., 2002; Wan et al., 2005). China is ever the world’s second largest producer of such pesti- cides. Hexachlorocyclohexanes (HCHs) and dichlorodiphenyltri- chloroethanes (DDTs) were widely used in China between 1950s and 1980s due to their low cost and high insecticidal efficacy. HCHs and DDT were officially banned in 1983, however, over the past 25 years, the total production of HCHs and DDT in China was about 4.9 and 0.4 million tons, respectively, accounted for 33% and 20% of the total world production, respectively (Fu et al., 2003). Although the usage and production of these anthropogenic pollutants were prohibited and the residue level of OCPs in the aquatic environment has considerably declined in the past years (Wu et al., 1999), these organic pollutants could still be a problem in various environmental compartments, especially in the estua- rine or marine sediments, which were usually regarded as an important sink of organic contaminants (Yang et al., 2005a). The sediments could also be a secondary contamination source to over- lying water due to the resuspension (Wu et al., 1999; Liu et al., 2008). The Bohai Sea (Bohai) in North China is a shallow marginal sea enclosed by Liaodong and Shandong Peninsulas, and is connected to the northern Yellow Sea by the Bohai Strait (Fig. 1). It has an area of 77,000 km 2 , and the average water depth is 18 m (Sündermann and Feng, 2004). In recent years, the rapid industrialization and urbanization around the coastal regions has resulted in a severe environmental stress in Bohai. Furthermore, the surrounding areas of Bohai have been OCPs’ production and application bases for sev- eral decades in China, especially for HCHs and DDTs. Several big manufactures of DDTs and HCHs such as the Dagu Chemical Com- pany and Tianjin Chemical Company were located in the lower reaches of the Hai River, one of the largest river basins around 0045-6535/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.chemosphere.2009.07.070 * Corresponding author. Address: Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China. Tel./fax: +86 21 65643117. E-mail address: guozgg@fudan.edu.cn (Z. Guo). Chemosphere 77 (2009) 663–672 Contents lists available at ScienceDirect Chemosphere journal homepage: www.elsevier.com/locate/chemosphere