Organochlorine pesticide residues ... Nyarko et al. ORGANOCHLORINE PESTICIDE RESIDUES IN SARDINELLA AURITA FROM THE COASTAL WATERS OF ACCRA-TEMA, GHANA AND THEIR POTENTIAL HEALTH RISKS E. Nyarko 1 , B. O. Botwe 1 , A. A. Bampoe 1 , S. Addo 1 , A. K. Armah 1 , W. J. Ntow 2 and P. Kelderman 3 1 Department of Oceanography & Fisheries, University of Ghana, Legon, Ghana 2 CSIR Water Research Institute, P.O. Box AH 38, Achimota, Ghana 3 UNESCO-IHE Institute for Water Education, P.O. Box 3015, 2601 DA Delft, The Netherlands ABSTRACT Sardinella aurita and seawater samples from the Accra-Tema coast of Ghana were analysed for organochlorine (OC) pesticides using gas chromatography (GC) with electron capture detection (ECD). Residues of DDTs (p,p’-DDT, p,p’-DDE, p,p’-DDD), hexachlorocyclohexane (HCHs - α- HCH, β-HCH and γ-HCH), endosulfan (α-endosulfan, β-endosulfan, endosulfan sulphate) and heptachlor were detected in fish at average concentrations ranging from 3.0 to 1235.0 μg/kg wet wt. These residues were, however, below the detection limit in seawater samples. Significant differences (p < 0.05) in residue levels were also observed across sites, decreasing from Chorkor to Kpone for seven (7) of the residues that were detected in S. aurita. Evaluation of hazard ratios (HRs) and the health risk associated with OC exposure from consumption of sardinellas re- vealed a probability of adverse health effect due to p,p’ -DDT, γ-HCH and heptachlor. Hence, p,p’-DDT, γ-HCH and heptachlor may be of particular health concern. INTRODUCTION Organochlorine (OC) pesticides have been used to control pests in agriculture and public health programmes. Due to their semi-volatility and persistence, they can be transported through the atmosphere to remote areas where they have never been used (Borghini et al., 2005). The impacts of pesticides on aquatic ecosystems have been well documented (Castillo et al., 1997; DeLorenzo et al., 2001), and due to their persistence and toxic nature, some nine (9) OCs have been targeted for global elimination. Ex- posure to OCs is of major concern due to their carcinogenic, persistent, highly bioaccumula- tive and toxic nature (Silberhorn et al., 1990; Hong et al., 1999). A number of investigators have reported an association between breast cancer and other neoplastic diseases in humans as a result of long-term exposure to OCs (Woodruff et al., 1994; Ahlborg et al., 1995). In addition, studies have shown that OCs such as DDT, dieldrin and PCB have endocrine dis- rupting capacities. Due to their persistence, the OCs can be found in the environment long after they have been released. Aquatic biota may potentially acquire OCs from the atmosphere, water and food and due to their lipophilicity, changes in OC con- centrations might also be related to lipid con- tent (Nakata et al., 2002). In spite of the fact that marine fin-fishes form an important com- Journal of Ghana Science Association, Vol. 13 No. 1 . June, 2011 39