title: Organic contaminants in the marine environment of Manila Bay, Philippines.
abstract: Organochlorine pesticides (OCs) and polychlorobiphenyls (PCBs) were determined in sediments and oysters' soft tissues (Cassostrea gigas) collected in selected sites of Manila Bay. Overall, the concentration levels were very low. In sediments, PCBs were the compounds present in higher concentrations, with Sigma13PCB congeners averaging 0.69 +/- 0.46 ng/g (dry weight), followed by SigmaDDT averaging 0.53 +/- 0.28 ng/g and Sigmachlordane with 0.26 +/- 0.28 ng/g. Concentrations measured in oysters averaged 20 +/- 17 ng/g (dry weight) for Sigma13PCB and were higher than SigmaDDT, with 9.5 +/- 2.4 ng/g, and Sigmachlordane, with 3.8 +/- 3.1 ng/g. No dissolved residues of polar compounds, such as herbicides, and organophosphorous and organochlorine pesticides were found in the bay water. In general, results showed that concentrations of organochlorine pesticide residues, such as DDT, hexachlorocyclohexane, chlordane, lindane, endosulfan, and heptachlor in sediments and oysters were low in comparison with other coastal areas in Asia, although PCB concentrations in oysters were relatively high in some zones of Manila Bay and indicative of loose control of industrial chemical waste discharges into the bay. Nevertheless, current concentrations of persistent organochlorine contaminants in sediments were under threshold effect levels (TELs) and chronic toxic effects are, thus, unlikely to generate impairment of marine biota in Manila Bay.
authors.affiliation: Marine Environment Laboratories, International Atomic Energy Agency, 4 Quai Antoine 1er, MC 98000, Monaco. carvalho@itn.pt
authors.forename: Fernando P
authors.initials: FP
authors.lastname: Carvalho
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Villeneuve
authors.forename: Chantal
authors.initials: C
authors.lastname: Cattini
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Tolosa
authors.forename: Cristina M
authors.initials: CM
authors.lastname: Bajet
authors.forename: Mariafe
authors.initials: M
authors.lastname: Navarro-Calingacion
mesh_terms: D016573:Agrochemicals / Q000032:analysis; D000818:Animals; D002706:Chlordan / Q000032:analysis; D003634:DDT / Q000032:analysis; D019015:Geologic Sediments / Q000032:analysis; D006540:Herbicides / Q000032:analysis; D001556:Hexachlorocyclohexane / Q000032:analysis; D007220:Industrial Waste / Q000032:analysis; D007306:Insecticides / Q000032:analysis; D009930:Organic Chemicals / Q000032:analysis*; D010125:Ostreidae; D010573:Pesticide Residues / Q000032:analysis; D010679:Philippines; D011078:Polychlorinated Biphenyls / Q000032:analysis; D012621:Seasons; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D016573:Agrochemicals; D006540:Herbicides; D007220:Industrial Waste; D007306:Insecticides; D009930:Organic Chemicals; D010573:Pesticide Residues; D014874:Water Pollutants, Chemical; D002706:Chlordan; D001556:Hexachlorocyclohexane; D003634:DDT; D011078:Polychlorinated Biphenyls