Equilibrium partitioning theory overestimates chlorobenzene concentrations in sediment porewater from lake Ketelmeer, the Netherlands

Concentrations of di, and trichlorobenzenes were determined in porewater and sediment of a sediment core from lake Keterlmeer, the Netherlands. Average in-situ partition conefficients for di, and trichlorobenzene. Concentrations of di- and trichlorobenzenes in porewater were 1 to 2 orders of magnitude lower than calculated from the sediment data using literature partition coefficients. In-situ partition coefficients differed from literature values for partition coefficients obtained in lab experiments by a factor of 8 to 160. Assuming that the low concentrations in porewater canbe attributed to the presence of a slow desorbing fraction it can be calculated that for most compounds studied more than 95% of the measured sediment concentrations was present in the slow desorbing fraction.