For many persistent, xenobiotic, hydrophobic compounds bioconcentration can be satisfactorily treated as a physical-chemical partitioning process between the lipid phases of an aquatic organism and the surrounding aqueous medium. 1,2 For example, bioconcentration factors (KB) for fish have generally been shown to be related to the n-octanol/water partition coefficient KOW. 36 Abiotic partition coefficients, particularly KOW, are useful predictors of environmental partitioning behavior in general. The measurement of KOW for new chemicals is, as noted by Watarai, 7 officially recommended in the OECD Chemical Testing Program. Both soil/water and sediment/water partition coefficients and aqueous solubility have been correlated with KOW. 8,9