Prediction of the partition coefficient of lipophilic compounds in the air-mammal tissue system.

A theoretical bioconcentration model for predicting the air-mammal tissue partition coefficient of lipophilic compounds has been developed. The tissue was considered to consist of three compartments, i.e. lipid, protein and water, in different proportions depending on the tissue considered. The model is based on equilibrium partitioning of the chemicals between the compartments and the atmosphere and requires the octanol-water partition coefficient (K(ow)), Henry's Law Constant (H) and the phase composition of the animal tissue as input information. The model was evaluated using experimental partition coefficients for 19 volatile chlorohydrocarbons and aromatic hydrocarbons. Predicted partition coefficients (Kba) for human blood and olive oil systems are in good agreement with the experimentally determined values. The model gave a lower level of precision with rat blood, rat muscle and rat liver systems and fairly consistently underestimated the experimental values by 22-62%.