Cr and As decrease lindane sorption on river solids

Abstract

The fate of a pollutant in water is modified by sorption onto solids and by interaction with other pollutants. Actual knowledge is mainly focussed on pollutant sorption by sediments, whereas little is known about the roles of natural biofilms and suspended particles. Moreover, few investigations report on the interaction of co-occurring pollutants. Here, we studied the sorption of the lindane pesticide by natural biofilms, suspended particles, and river sediments using batch experiments. We also measured the effects of Cr(VI) and As(V) on lindane sorption. Results show that more lindane is adsorbed by biofilms than by suspended particles and sediments on a total mass basis, whereas the sediments had a higher lindane sorption capacity per unit mass organic carbon than suspended particles and biofilms. Co-occuring Cr(VI) or As(V) decreased lindane sorption on the biofilms by about 48 %. To our best knowledge, this is the first report showing that Cr(VI) and As(V) decrease the sorption of hydrophobic organic contaminants on river solids.