Profile analysis of polycyclic aromatic hydrocarbons and metal content in sediment layers of a lake.

The question is investigated whether polycyclic aromatic hydrocarbons (PAH) in the annual sediment layers of a lake mainly result from air dust pollution. Sample layers taken from drilling cores going back to 1915 show no significant differences at the forest shore (no buildings) during this period. In contrast, samples taken from a built-up area of the shore (with a highway and a main railway line) show today 5 times the amount of PAH compared with 1915. The same trend is observed in the content of Zn, whereas Pb, Fe, Cr, Ni, Cu and Mn levels are constant. Identification or characterization of PAH was accomplished by comparison of the retention times and mass spectrometry of authentic compounds. Sixty-four PAH are described. The results indicate that the burden of carcinogenic PAH air pollutants has increased 5-fold from 1915-1970.