The usefulness of an artificial membrane accumulation index for estimation of the bioconcentration factor of organophosphorus pesticides.

The bioconcentration factor (BCF) is an important ecotoxicological parameter that describes the accumulation of chemicals in organisms. As many studies have reported, logBCF has good correlation with the logarithm of the 1-octanol/water partition coefficient, logP(oct), for chemicals that have logP(oct) values below about 6 and are not significantly metabolized in organisms. In this study we measured a membrane accumulation index, that is, the membrane partition (P(M)) of organophosphorus pesticides using the parallel artificial membrane permeation assay (PAMPA) to clarify whether this index is useful for the estimation of BCF. As a result, logP(M) had good correlation with logP(oct) except for iprobenfos and edifenphos. Furthermore, logBCF in five kinds of fish, especially male guppy correlated better with logP(M) than logP(oct). The results indicate that logP(M) is a better index for predicting logBCF than logP(oct). We have already reported that PAMPA permeability coefficients could predict human oral absorption of compounds, including hydrophobic chemicals and agrochemicals. Since it is expected that both human oral absorption and BCF can be estimated simultaneously using PAMPA, PAMPA is useful for exposure estimation to humans of chemicals in the environment.