U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Main content area

Organic Contaminants in the Marine Environment of Manila Bay, Philippines

Carvalho, Fernando P., Villeneuve, Jean-Pierre, Cattini, Chantal, Tolosa, Inmaculada, Bajet, Cristina M., Navarro-Calingacion, MariaFe
Archives of environmental contamination and toxicology 2009 v.57 no.2 pp. 348-358
DDT (pesticide), HCH (pesticide), chemical control, chlordane, coasts, endosulfan, heptachlor, herbicides, industrial wastes, lindane, long term effects, organophosphorus pesticides, oysters, pesticide residues, polar compounds, polychlorinated biphenyls, sediment contamination, sediments, Philippines
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 Σ13PCB congeners averaging 0.69 ± 0.46 ng/g (dry weight), followed by ΣDDT averaging 0.53 ± 0.28 ng/g and Σchlordane with 0.26 ± 0.28 ng/g. Concentrations measured in oysters averaged 20 ± 17 ng/g (dry weight) for Σ13PCB and were higher than ΣDDT, with 9.5 ± 2.4 ng/g, and Σchlordane, 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.