Estimation of bioconcentration factors of nonionic organic compounds in fish by molecular connectivity indices and polarity correction factors

A bioconcentration factor (BCF) estimation model for a wide range of nonion ic organic compounds was developed on the basis of molecular connectivity i ndices and polarity correction factors. The nonlinear topological modeling using polarity correction factors resulted in the best BCF estimation quali ty for all of the 239 compounds studied, with a mean absolute estimation er ror of 0.478 log units. Residual analysis indicated that the estimation err ors came from many sources including BCF measurement, test species, and sel ection of descriptors. Statistical robustness of the developed model was va lidated by modified jackknifed tests where random deletion of a set of comp ounds and specific deletion of a class of compounds were both performed. Co mparison between the MCI-based (molecular connectivity indices) model and a K-ow-based (octanol/water partition coefficient) model revealed that the B CF estimation based on topological parameters was as good as that achieved by K-ow. (C) 2000 Elsevier Science Ltd. All rights reserved.