THE MOBILITY OF PERCHLOROETHYLENE IN GLACIAL SEDIMENT IN SOUTHEASTERN NEW YORK: INSITE INTO THE EFFECTS OF CARBONACEOUS SORBENTS

The fate and transport of hydrophobic organic contaminants in an aquifer is affected by the type and quantity of carbonaceous matter (CM) present. CM is defined as all carbon containing material (humic matter, black carbon, kerogen etc.) except for carbonates. CM sorbs organic pollutants either through absorption, into the CM particle, or adsorption, onto the CM particle. Absorption is linear and the dominant sorption mechanism at high concentration ranges for pollutants. At low concentration ranges of pollutants non-linear adsorption dominates. Batch sorption tests for perhchloroethylene (PCE), a frequently detected groundwater contaminant, were performed on glacial sediment from southeastern New York displaying non-linear sorption. At low concentrations (5µg/L) of PCE high sorption values of 2.8 mg/L were found, while at high concentrations (~100000µg/L) of PCE low sorption values of 0.32mg/L were found. Different types of CM display different mechanisms of sorption. This pattern of non-linear sorption in the sediment is indicative of high black carbon and kerogen content along with a low humic matter content.