Maternal transfer and in ovo exposure of organochlorines in oviparous organisms: A model and field verification
Because early life stages of many species exhibit a greater toxicological sensitivity to contaminants than the adult life stages, knowledge of the exposure of contaminants during embryonic development is a crucial prerequisite for toxicological risk assessment. This study presents a chemical equilibrium model for estimating the maternal transfer and resulting exposure of developing embryos in eggs of several classes of oviparous organisms to hydrophobic organic chemicals. The model is tested against (i) the results of a field study, including the analysis of 44 chemicals in eggs and maternal tissues of 6 fish species and snapping turtles, and (ii) literature data for 8 additional fish and 3 bird species. Lipid normalization of egg and maternal concentrations reduces the variability in observed egg-to-maternal tissue concentration ratios between species by approximately 20-fold. The majority of observed lipid normalized egg/maternal tissue concentration ratios for individual chemicals and fish were not sig...