Transport of nonpolar organic compounds from surface water to groundwater. Laboratory sorption studies

Abstract

Laboratory batch and column experiments have been conducted to elucidate the sorption behavior of nonpolar organic compounds (e.g., halogenated alkenes and benzenes) in a river water-groundwater infiltration system. For the low concentrations typical of the environment, sorption equilibria can be described by the equation <I>S</I> = <I>K</I>_p<I>C</I>, where <I>S</I> = concentration in the solid phase, <I>K</I>_p = partition coefficient, and <I>C</I> = concentration in the liquid phase. For a variety of sorbents, it was found that the partition coefficient <I>K</I>_p^Z of a particular compound Z can be estimated from its 1-octanol/water partition coefficient <I>K</I>_OW^Z and from the organic-carbon (OC) content <I>f</I>_OC (fraction organic carbon) of the sorbents if <I>f</I>_OC is greater than 0.001: log <I>K</I>_p^Z = 0.72 log <I>K</I>_OW^Z + log <I>f</I>_OC(s) + 0.49. Sorption was found to be reversible, but sorption kinetics may have an effect on material transport over the range of flow velocities encountered in aquifers. The conclusions of this study are applicable to a wide range of sorption and transport problems including artificial groundwater recharge and leaching of pollutants from landfills.