1e:T54a,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 S = K_pC, where S = concentration in the solid phase, K_p = partition coefficient, and C = concentration in the liquid phase. For a variety of sorbents, it was found that the partition coefficient K_p^Z of a particular compound Z can be estimated from its 1-octanol/water partition coefficient K_OW^Z and from the organic-carbon (OC) content f_OC (fraction organic carbon) of the sorbents if f_OC is greater than 0.001: log K_p^Z = 0.72 log K_OW^Z + log f_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.1f:T414,The behavior of organic micropollutants during infiltration of river water to groundwater has been studied at two field sites in Switzerland. In agreement with predictions from model calculations, persistent organic chemicals exhibiting octanol/water partition coefficients smaller than about 5000 moved rapidly with the infiltrating river water to the groundwater. The biological processes responsible for the "elimination" of various micropollutants (e.g., alkylated and chlorinated benzenes) occurred predominantly within the first few meters of infiltration. Alkylated benzenes were "eliminated" at faster rates than 1,4-dichlorobenzene. Anaerobic conditions in the aquifer near the river hindered the biological transformation of 1,4-dichlorobenzene. Among the compounds that were found to be persistent under any conditions were chloroform, 1,1,1-trichloroethane, trichloroethylene, and tetrachloroethylene. With respect to such chemicals, bank filtration is ineffective as a first step in the treatment of river water for water supplies.

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