Risk assessment of organohalogenated compounds in water bird eggs from South China.

Organohalogen compounds, the pesticides aldrin, dieldrin, endrin, hexachlorobenzene, mirex, Sigmachlordanes, SigmaDDTs, Sigmaheptachlors, Sigmatoxaphenes, and the industrial chemicals SigmaPCBs and SigmaPBDEs, as well as total dioxin-like equivalents (TEQH4IIE-luc), were measured in eggs of two Ardeid species, the little egret (Egretta garzetta) and black-crowned night heron (Nycticorax nycticorax) from three port cities along the South China coast: Hong Kong, Xiamen, and Quanzhou. SigmaDDTs was the predominant and most abundant residue, occurring at concentrations ranging from 2.7 x 10(3) to 8.7 x 10(4) ng/g lipid wt. The greatest concentrations of the studied compounds were observed in eggs collected from Hong Kong, with the exception of SigmaDDTs, which occurred atthe greatest concentrations in eggs from Quanzhou Bay and Xiamen Harbor. Concentrations of SigmaPBDEs were greater in eggs from Quanzhou Bay and Xiamen Harbor, possibly because of rapid industrialization in these areas. Total concentrations of dioxin-like PCBtoxic equivalents (TEQs), measured as the aryl hydrocarbon receptor (AhR)-mediated responses of the H4IIE-luc bioassay (TEQH4IIE-luc), were greatest in Hong Kong samples. A risk assessment of the relatively great concentrations of SigmaDDEs and dioxin-like (coplanar) PCBs in the eggs (threshold levels: 2.8 microg/g wet wt. and 5 pg/g wet wt., respectively) predicted that concentrations of these compounds would be expected to affect some proportion of the Ardeid populations studied.