Content and Potential Sources of Pahs and Pcbs in Soils and Bottom Sediments of the Siberian Arctic

Assessment of environmental pollution in the Arctic is becoming increasingly important in the terms of active industrial development and global climate change. Soils and bottom sediments from the northern regions of Western and Central Siberia were analyzed for persistent organic pollutants including polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). Total concentrations were calculated and trends in the relative distribution of individual PAH and PCB groups were identified in soils and bottom sediments across Arctic subregions defined by CAFF. Potential pollution sources were identified using nonmetric multidimensional scaling (nMDS). The characteristics of lake bottom sediment pollution due to oil and gas production were examined. Total PAHs in soils and bottom sediments of background areas ranged from 0.3 to 112.6 µg/kg dry weight, increasing northward. Total PCBs ranged from 0.2 to 9 µg/kg dry weight, regardless of the subregion. It was shown that PAH contamination occurred predominantly from light 2- and 3-ring compounds. Ordination using non-metric multidimensional scaling showed a decrease in the diversity of PAH compositions in the studied background soils and bottom sediments depending on latitude and distance to the nearest industrial center, which reflects the influence of climate and atmospheric transport. In comparison to background values, lake bottom sediments in the oil and gas production areas showed an increase in the overall content and fraction of heavy PAHs. No significant differences were found in the total content or composition of PCBs in lake bottom sediments from oil and gas production areas compared to background levels.