Polycyclic Aromatic Hydrocarbons in Bottom Sediments of Selected Anthropogenic Reservoirs in Terms of Catchment Area Development

Abstract

The polycyclic aromatic hydrocarbon (PAH) concentration in the bottom sediments of the selected dam reservoirs is related to the catchment area size and length of the watercourse that supplies the reservoir. The anthropopressure increases the ratio of the PAH concentration sum G4 group to the G1 group. For the urban-industrial catchment area, the ratio is 1; for the agricultural and agricultural-forestral catchment area, the ratio is between 4 and 9. The elongated down time of surface run-offs helps to retain and degrade 2- and 3-ring PAHs, which is reflected in the high G4:G1 ratio value. Consequently, the pollutants are quickly delivered to the reservoirs and deposited in the bottom sediments. Under such conditions, the G4:G1 ratio is 1. The way in which the catchment area is developed shapes the proportions between the PAH groups that differ in the number of aromatic rings in their molecules. The toxicity, mutagenicity, and carcinogenicity coefficients calculated for the bottom sediments demonstrate that the limnic ecosystems supplied with water from the watercourses with urban-industrial catchment areas are far more threatened than the reservoirs supplied with watercourses with the agricultural catchment areas or catchment areas with a significant share (40–50%) of farming land.