Polycyclic aromatic hydrocarbons in various Lithuanian water bodies and a positive matrix factorization-based identification of pollution sources

In this study, results on PAHs distribution, origin and ecological risks from several surveys are combined with a special focus on naphthalene. The study area comprises a large part of the Lithuanian territory and includes two biggest Lithuanian rivers, Nemunas and Neris (sampling locations with different hydrodynamics and varying anthropogenic pressure), four different lakes and the central part of the Curonian Lagoon. ∑16PAHs concentrations in the surface sediment ranged between 74.5 and 6377 ng g-1 dw. In 9 locations out of 14, naphthalene concentration exceeded TEL and posed a threat to the environment. Naphthalene was a significant contributor to the total PAHs concentration in the study area with concentrations ranging from 0.78 to 106 ng g-1 dw. Despite the highest naphthalene concentration recorded in Lake Talkša, naphthalene had only a minor contribution to the PAH profile in this lake. Even a lower impact of naphthalene was observed in the Curonian Lagoon. Naphthalene was found to be the prevailing compound in the Nemunas River Delta region, in a relatively clean Lithuanian Lake Dusia and in some Neris River locations. The highest contribution of naphthalene was observed in the areas with low urbanization degree, but close to peatlands. The main naphthalene source in the study area might be related to peatlands, albeit additional naphthalene sources, such as food cooking, burning of agricultural residues, wood and coal could not be completely rejected either. The sources of other PAHs are attributed to the vehicular emission, emissions from industry, biomass and coal burning.