Relationships between pesticides and organic carbon fractions in sediments of the Danshui River estuary and adjacent coastal areas of Taiwan Chin-Chang Hung a, * , Gwo-Ching Gong a , Hung-Yu Chen b , Hwey-Lian Hsieh c , Peter H. Santschi d , Terry L. Wade e , Jose L. Sericano e a Institute of Marine Environmental Chemistry and Ecology, National Taiwan Ocean University, 2 Pei-Ning Road, Keelung 202, Taiwan, ROC b Department of Marine Environmental Informatics, National Taiwan Ocean University, Keelung 20224, Taiwan, ROC c Research Center for Biodiversity, Academia Sinica, 128 Sec. 2, Academia Road, Nankang, Taipei 115, Taiwan, ROC d Laboratory for Oceanography and Environmental Research (LOER), Texas A&M University at Galveston, 5007 Avenue U, Galveston, TX 77551, USA e Texas A&M University, Geochemical and Environmental Research Group (GERG), College Station, TX 77845, USA Received 9 August 2006; received in revised form 11 November 2006; accepted 26 November 2006 Total organic carbon and black carbon regulate the distribution of trace organic pollutants in sediments of the Danshui River estuary and adjacent coastal areas of Taiwan. Abstract In order to understand the fate of pesticides in marine environments, concentrations of pesticides and different carbonaceous fractions were determined for surface sediments in the Danshui River and nearby coastal areas of Taiwan. The major compounds detected were tetrachloro- benzene, HCHs, chlordane, aldrin, DDDs, DDEs and DDTs. Total concentrations of pesticides in the sediments ranged from not detectable to 23 ng g 1 , with the maximum value detected near the discharge point of the marine outfall from the Pali sewage treatment plant. These results confirm that pesticides persist in estuarine and nearby coastal environments of the Danshui River well after their ban. Concentrations of total pesticides significantly correlate with concentrations of total organic carbon and black carbon in these sediments, suggesting that total organic carbon and black carbon regulate the distribution of trace organic pollutants in fluvial and coastal marine sediments. Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Pesticide; Sediments; POC; Black carbon; Danshui River; Taiwan 1. Introduction Anthropogenic contaminants, such as persistent organic pollutants (POPs), are produced, and temporarily deposited in riverine drainage basins, and subsequently transported down-river over time, to end up, in ports, in estuarine and coastal sediments. The danger is that lipophilic POPs bioaccu- mulate in marine organisms and are transferred up the food chain. Thus, many of these POPs have been banned for two decades because of concern about detrimental effects on eco- system and human health. However, their residues still persist in the environment due to their long half-life, about 20e30 years (Woodwell et al., 1971; Sericano et al., 1990). Taiwan is located in a subtropical region of the world that has remarkably distinct dry and wet seasons. In the dry sea- sons, most of the pollutants (from point sources or non-point * Corresponding author. Tel.: þ886 2 2462 0330. E-mail address: cchung@mail.ntou.edu.tw (C.-C. Hung). 0269-7491/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.envpol.2006.11.036 Environmental Pollution 148 (2007) 546e554 www.elsevier.com/locate/envpol