Bioavailability of polycyclic aromatic hydrocarbons and polychlorinated biphenyls in rats from naturally contaminated soils - Preliminary evaluation of the influence of soil parameters

In order to assess the bioavailability of organic pollutants (polycyclic ar omatic hydrocarbons [PAHs], polychlorobiphenyls [PCBs]) in polluted soils, male laboratory rats were exposed during 3 d and one night to two types of soil. These soils were highly polluted by PAHs (F-2 soil) and by PCBs (S-3 soil). They were diluted (1:1) either with an organic or a mineral matrix. Those matrices had different characteristics, and the purpose was to determ ine the influence of several soil parameters (organic matter) on the pollut ants' bioavailability. Two categories of biomarkers were used: pollutant's burden and activities of microsomal liver and lung's cytochrome P450 1A-mon ooxygenase, namely, ethoxyresorufin-O-deethylase (EROD) activities. Absorpt ion differed between exposed rats, depending on the pollutant and on the or gan considered. Their EROD activity was well correlated with PAH and PCB bu rden, respectively. Moreover, EROD activity and pollutants burden in both o rgans depended on the dilution performed. The PAH bioavailability was lower after a dilution with organic matrices. In fact, those matrices had both t he highest organic matter concentration and the lowest granulometry and app eared to adsorb more. Thus, organic pollutant bioavailability varies accord ing to the soil characteristics. The most important parameters seemed to be organic matter and granulometry. The EROD activity and CYP1A1 dosage were good biomarkers and closely monitored the differences in bioavailability.