Geochromatographic migration of oil pollution from a heating plant to river sediments

Many pollution sources are difficult to identify because pollutants are transported far away into complex environments. In particular, the mechanisms of petroleum migration in sediments are poorly known. Here, we studied two sediments from the circuit of a heating plant and three sediments located at 100, 200 and 300 m away from the plant. Saturated hydrocarbons were isolated and group composition was determined by column chromatography. n -Alkanes, terpanes and steranes were analyzed by gas chromatography-mass spectrometry. Results show that the amount of short n -alkanes increases during migration, which indicates the migration mechanism. Results on steranes reveal a geochromatographic migration of the oil, where the fastest eluting stereoisomers display the longest migration path. Changes in the distribution of biological markers are explained by migration in water.