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, log BCF has good correlation with the logarithm of the 1-octanol/water partition coefficient, log Poct, for chemicals that have log Poct 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 (PM) 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, log PM had good correlation with log Poct except for iprobenfos and edifenphos. Furthermore, log BCF in five kinds of fish, especially male guppy correlated better with log PM than log Poct. The results indicate that log PM is a better index for predicting log BCF than log Poct. 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.