A Framework for assessing the sorption potential of emerging organic contaminants in soil systems.

Dharni Vasudevan, Associate Professor
Chemistry and Environmental Studies
Bowdoin College
Brunswick, ME

Urban activity, agricultural productivity, reliance on biofuels, and use of personal care products results in the inadvertent or intentional release of organic chemicals into the natural environment.  The potential toxicity of these chemicals poses an important risk to exposed human and wildlife populations.  Over the last decade, concerns over the fate and ecotoxicological effects of organic compounds in the environment have shifted from nonpolar compounds (e.g., DDT and PCBs) to polar and ionogenic compounds (e.g., pesticides, pharmaceuticals, and personal care products).  This shift was an understandable consequence of several decades of research which resulted in our advanced understanding of the fate of nonpolar compounds and construction of elegant quantitative models capable of predicting nonpolar compound sorption from easily accessible chemical and soil properties.  In addition, the recognized persistence and bioaccumulation of nonpolar compounds has directed the development of polar and ionogenic substitutes with shorter environmental half-lives and less biotic uptake. As such, the several emerging contaminants are polar and ionogenic compounds (PICs).  PICs, often show complex pH dependent aqueous speciation and have the ability interact with soil surfaces via several independent mechanisms.  This seminar will address the importance of chemical structure, soil mineralogy and surface site availability on the extent of PIC sorption in soil systems.