Pergamon 0045-6535(94)00207-X Chemosphere, Vol.29, No. 4, pp. 657-669,1994 ElsevierScience Ltd Printed in GreatBritain 0045-6535/94 $7.00+0.00 ESTIMATION OF AQUEOUS SOLUBILITY, OCTANOI./WATER PARTITION COEFFICIEN:r, AND HENRY'S LAW CONSTANT FOR POLYCHLORINATED BIPHENYI.~ USING UNIFAC An Li 1, William J. Doucette2, Anders W. Andren *1 1Water Chemistry Program, University of Wisconsin-Madison 660 N. Park Street, Madison, W153706, USA 2Utah Water Research Laboratory, Utah State University Logan, UT 84322, USA (Received in Germany3 March 1994; accepted 20 June 1994) Abstract The ability of the UNIFAC group-contribution model to accurately predict aqueous solubility (S), 1- octanol/water partition coefficient (Kow) and Henry's law constant (HLC) for polychlorinated biphenyls (PCBs) was evaluated by comparing experimental values of S, Kow and HLC with those estimated using UNIFAC- derived activity coefficients. Five different sets of interaction parameters tables were evaluated along with two previously published regression equations designed to correct for systematic errors. The best estimates of S, Kow and HLC were obtained using vapor-liquid equilibrium (VLE)-based parameter table published in 1982 by Gmehling et al., with modified values for aromatic chlorine and water interaction parameters. 657