DEPOSITION FLUXES OF POLYCYCLIC AROMATIC HYDROCARBONS IN THE BOTTOM SEDIMENTS OF LAKE PIHKVA
Traditionally the elevated concentrations of PAHs in the bottom sediments of Lake Peipsi are explained by the influence of oil shale industry. To estimate the role of Narva Power Plants (Narva PP) in the deposition of PAHs, we investigated the 210 Pb dated sediment core from Lake Pihkva, where the influence of oil shale industry should be minimal. The distribution of 15 individual PAHs was established, the observed levels of ΣPAHs ranged between 75 and 345 ng/g. PAHs with 4-5 rings implying petrogenic activity accounted for 74 to 87% of ΣPAHs, which is higher than in a similar investigated profile in Lake Peipsi sensu stricto. It means that the role of oil shale industry in PAHs accumulation is strongly overestimated and there should be many other sources whose role needs further investigation.