Prediction of the bioaccumulation potential of alkylphenols using in vitro biotransformation rates and corrections for the fraction unbound in S9

Abstract

To better predict the bioaccumulation potential of chemicals without animal tests, the biotransformation rates of a series of alkylphenols were measured using liver S9 fractions from rainbow trout (RT-S9). Due to steric hindrance, the reaction rate of some chemicals with the tert-butyl moiety was slower than the QSAR-based prediction. Based on the observed rate constants and the unbound fractions of substrates in the RT-S9 reaction system, the bioconcentration factors (BCFs) were estimated by a previously proposed model. Calculated BCF values were well consistent with the bioaccumulation potential determined by the animal tests.