ESTIMATING THE EFFECTS OF DISPERSED ORGANIC POLYMERS ON THE SORPTION OF CONTAMINANTS BY NATURAL SOLIDS .2. SORPTION IN THE PRESENCE OF HUMIC AND OTHER NATURAL MACROMOLECULES

A triphase distribution model was used in conjunction with experimental observations to characterize the effects of humic polymers dispersed in an aqueous phase on the sorption of hydrophobic organic compounds from that phase by natural solids. The organic compound-humic substance binding constants employed in the model were estimated by using a partition equation that takes into account the solubility of the solute in both the aqueous and organic polymer phases as developed in the first paper of this two-part series. Experimental results and model predictions indicate that the sorption of moderately hydrophobic compounds by lacustrine sediments is relatively unaffected by the presence of humic polymers, but that the sorption of highly insoluble organic contaminants by the same sorbents is sensitive to small amounts of background organic polymers. The observations support earlier analyses by other investigators regarding the impact of the organic subphases on the fate and transport of pollutants in natural aquatic systems. © 1990, American Chemical Society. All rights reserved.