Sorption of chlorinated C1- and C2-hydrocarbons and monocyclic aromatic hydrocarbons on sea sediment

The sorption of chlorinated C1- and C2-hydrocarbons and monocyclic aromatic hydrocarbons on sea sediment was studied with a miscible displacement technique. Detection was done either by on-line UV-detection or off-line GC-analysis. Equilibrium partitioning coefficients between the salt water phase and the marine sediment were determined for 11 compounds by fitting their breakthrough curves to a local sorption equilibrium model. Based on the obtained partitioning coefficients and on the measurement of the organic carbon content of the sediment, the sorption into the organic carbon fraction was considered. Log Koc data (Koc = organic carbon-water partitioning coefficient) were calculated. A linear relationship between the log Koc values and the log Kow data (Kow = octanol-water partitioning coefficient) was found (r = 0.94, n = 11). However, the sorption was lower than expected from the log Kow data. Finally, the implications of the experimental results for the sorption behaviour of the compounds in the marine environment were evaluated. It was concluded that the sea sediment does not act as an important sink for these anthropogenic compounds.