Levels of polychlorinated biphenyls and organochlorine pesticides in edible shellfish from Xiamen (China) and estimation of human dietary intake.

Xiamen is a representative coastal city in China. Shellfish is widely consumed by local people. A broad spectrum of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were measured in representative shellfish from Xiamen. Despite being banned many years ago, these chemicals were still detected at varying levels. The total PCB levels ranged from 0.48 to 3.28 ng/g wet wt. for the shellfish surveyed. The tetra-, penta- and hexa-PCB congeners were found to be predominant. The estimated WHO-TEQ PCB intakes through shellfish consumption ranged from 0.063 to 0.102 pg/kg body wt. for Xiamen adults and children, which were significantly lower than tolerable weekly intake. Among OCPs, DDTs were predominant, followed by aldrin-like chemicals and endosulfans. The increase in aldrin-like chemicals and endosulfans, and the decrease in DDTs were observed in this study when compared to historical data in Xiamen. HCHs, chlordanes, HCB, heptachlors and mirex were detected with low concentrations in the shellfish. The estimated intakes of OCPs were several orders lower than tolerable daily intakes. However, the high carcinogenic risk of aldrin and dieldrin were found in the measured shellfish species. p,p'-DDD, p'p-DDT, α-HCH and β-HCH in certain species should also be concerned for their potential carcinogenic risks.