The use of chorioallantoic membranes as predictors of egg organochlorine burden

Abstract

Abstract The distribution of organochlorine pollutants between yolks, embryos, and chorioallantoic membranes (CAMs) in pipping eggs of Audouin's gulls from the Ebro Delta was determined to assess the usefulness of CAMs as surrogates for predicting whole egg pollutant burdens. The reliability of predictions was checked using a concordance analysis based on four different parameters. The most abundant pollutants found were PCBs and DDTs, whereas levels of HCHs were much lower. Generally, the largest concentrations of contaminants were found in yolk sacs, followed by embryos and CAMs. The latter contained only 1.21% of the total concentration of organochlorines detected. Results show that CAMs could provide good predictions only for those pollutants being almost completely excreted to the CAM (e.g., hexachlorocyclohexanes, PCB52, and DDD). In the other organochlorines tested, the prediction obtained is too weak to recommend the use of CAMs for the estimation of their total burden in the eggs of Audouin's gull. This suggests that the reliability of CAMs as surrogates should be tested for each chemical and species, prior to their use in nonlethal monitoring programs.