Characterization and composition of heavy metals and persistent organic pollutants in water and estuarine sediments from Gao-ping River, Taiwan Ruey-an Doong a, * , Shih-hui Lee a , Chun-chee Lee a , Yuh-chang Sun a , Shian-chee Wu b a Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 101, sec. 2, Kuang-Fu Road, Hsinchu 30013, Taiwan b Graduate Institute of Environmental Engineering, National Taiwan University, 10670 Taipei, Taiwan Abstract The objective of this study was to determine the concentrations and possible sources of heavy metals and persistent organic pollutants (POPs) in water and estuarine sediments from Gao-ping River in order to evaluate the environmental quality of aquatic system in south- ern Taiwan. High concentrations of heavy metals including Cr, Zn, Ni, Cu and As, ranging from 10.7 to 180 mg/kg-dry weight (dw), were detected in sediments from Gao-ping River. When normalized to the principal component analysis (PCA), swinery and electroplat- ing wastewaters were found to be the most important pollution sources for heavy metals. Of various organochlorine pesticide (OCP) residues detected, aldrin and total-hexachlorocyclohexane (HCH) were frequently found in sediments. The total concentrations of OCPs were in the range 0.47–47.4 ng/g-dw. Also, the total-HCH, total-cyclodiene, and total-dichlorodiphenyltrichloroethane (DDT) were in the range 0.37–36.3, 0.21–19.0, and 0.44–1.88 ng/g-dw, respectively. The polychlorinated biphenyl (PCB) concentrations in sediments from Gao-ping River ranged between 0.37 and 5.89 ng/g-dw. The PCB concentrations are positively correlated to the organic contents of the sediment particles. a-HCH was found to be the dominant compound of HCH in the sediments, showing that long-range transport may be the possible source for the contamination of HCH in sediments from Gao-ping River. In summary, trace amounts of POPs in estuarine sediments from Gao-ping River were detected, showing that there still exist a wide variety of POP residues in the river sedi- ments in Taiwan. These POP residues may be mainly from long-range transport and weathered agricultural soils, while heavy metal con- tamination is primarily from the swinery and industrial wastewaters. Ó 2008 Elsevier Ltd. All rights reserved. Keywords: Gao-ping River; Heavy metals; Persistent organic pollutants (POPs); Organochlorine pesticides (OCPs); Polychlorinated biphenyls (PCBs); Sediments 1. Introduction Persistent organic pollutants (POPs) such as organo- chlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) and heavy metals are ubiquitous contaminants in different compartments of the environments (Hong et al., 1999; Doong et al., 2002a; Martin et al., 2003; Fu and Wu, 2005, 2006). In spite of numerous countries having withdrawn the registered usage of POPs for many years, these man-made chemicals still persist at considerable lev- els worldwide (Cleemann et al., 2000; Feng et al., 2003; Verweij et al., 2004; Wurl and Obbard, 2005; Chau, 2006; Katsoyiannis, 2006). These compounds are generally gen- erated by anthropogenic processes and can be introduced into the environments through various routes. Due to their toxic, mutagenic, and carcinogenic characteristics, these persistent compounds are considered to be hazardous to the biota and environments. Also, these compounds are strongly sorbed onto the surface of particles associated with the organic content of solid-phase matrix and can be deposited to the underlying sediments. Therefore, the 0025-326X/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.marpolbul.2007.12.015 * Corresponding author. Tel.: +886 3 5726785; fax: +886 3 5718649. E-mail address: radoong@mx.nthu.edu.tw (R.-a. Doong). www.elsevier.com/locate/marpolbul Available online at www.sciencedirect.com Marine Pollution Bulletin 57 (2008) 846–857