Sorption of Estrogens to Soil and Manure Colloids with Implications for Transport.

            The application of animal manures and bio-solids to soil as fertilizer requires an understanding of the fate and transport of associated contaminants.  Estrogenic compounds that occur in manure are typically non-polar, and upon application they are strongly adsorbed to soil organic matter. Adsorption limits their mobility in the aqueous phase but presents another possible vector for transport.  Colloidal movement in soils has been long-recognized in the context of soil genesis, but only recently has it been considered as a mechanism for contaminant transport.  The movement of colloids in soil may facilitate the transport of estrogens to drainage systems and ultimately to surface water where the effects on aquatic ecosystems are uncertain but worrisome.

            Previous studies have shown that estrogenic compounds have high sorption affinities for soils and most notably of soil organic matter.  There have been numerous transport studies that have investigated the mechanisms of soluble estrogen movement, but few have explicitly considered the possibility of colloid facilitation in transport.  The goal of this study is to investigate the role that colloids play in the sorption and potential transport of 17β-estradiol and estrone. Results from batch and column studies of three soils with contrasting characteristics and using both soil and manure colloids will be reported.