Spatial distribution, ecological risk and sources of polycyclic aromatic hydrocarbons (PAHs) in water and bottom sediments of the anthropogenic lymnic ecosystems under conditions of diversifi ed anthropopressure

Abstract

The research determined the concentrations of selected polycyclic aromatic hydrocarbons (PAHs) in water and sediments of Klodnica River reservoirs and distribution depending on number of rings, ecotoxicological impact on studied ecosystems and possible sources of origin. Samples were subjected to qualitative and quantitative analysis by gas chromatography coupled with a GC-MS mass detector, using a ZB-5MS column and electron ionization. The sum of 16 PAHs in water ranged 0.111-0.301 μg/L (mean 0.200 μg/L) in Dzierzno Duze, 0.0410-0.784 μg/L (mean 0.303 μg/L) in Dzierzno Male and 0.0920-1.52 μg/L (mean 0.596 μg/L) in Plawniowice. While in sediments respectively: 17.5-37.2 μg/g (mean 26.8 μg/g), 4.33-8.81 μg/g (6.43 μg/g) and 2.27-9.50 μg/g (5.30 μg/g). The concentration of PAHs in sediments of reservoirs, which spatial management of the catchment area accounts for over 90% of agricultural and forest land, was up to eight times lower than in sediments of the reservoir which is 69%, while built-up and transport areas are 24%. In sediments of Dzierzno Male and Plawniowice PAHs with 5 and 6 rings dominate, while in Dzierzno Duze - 2 and 3 rings. Higher concentrations of PAHs with higher molecular weight, found in the bottom water layers, confirm the role of the sedimentation process in the transport of these compounds in reservoirs. Assessment of sediment quality, based on ecotoxicological criteria, showed that PAHs may cause toxic effects in Dzierzno Duze, while in Dzierzno Male and Plawniowice can cause sporadic adverse effects. The likely source of PAHs in reservoirs is low emissions.