Hysteretic Desorption of Perfluorooctane Sulphonates within Sediment Components under Aerobic and Anoxic Conditions

The fate of organic contaminants in sediment can be better accurately predicted through knowledge of desorption. Complex formation between perflurooctane sulphonates (PFOS) and active sites on sediment components, especially, the level of organic matter plays significant role in desorption process. Assessment of successive desorption steps shows that the percent of expected desorption at constant distribution coefficient is better described by ideal and linear model. Desorption of PFOS from the various component at varied organic carbon contents was observed to follow a linear isotherm. Significant negative correlation (R2=0.934) was observed between fractional desorption of PFOS and percent organic carbon content of each sediment component. The study observed that significant percentage of initially desorbed PFOS is readily available to partition into the porewater as freely dissolved PFOS. Our findings suggest the stimulation of iron (III) reduction for the bioremediation of subsurface environments contaminated with redox active contaminants such as PFOS.