Soil sorption of 20 PCB congeners and six chlorobenzenes.

The soil sorption of six chlorobenzenes and 20 PCB congeners was studied by allowing aqueous trace solutions (ppb) of transformer fluids to equilibrate with 3-6 different soils. Linear relations were found between distribution constants and soil organic carbon content. Sorption was favored by a high degree of chlorination and the absence of ortho-substitution in the biphenyl. Sorption kinetics seemed to be first-order controlled (two steps) with rate constants in the order of many hours. We present correlations between sorption data and published physical data, which will be useful for modeling the transport and the fate of PCBs and chlorobenzenes in the environment.