The comparison of sediment contamination in the area of estuary and the lower course of the Odra before and after the flood of summer 1997

The concentration of heavy metals (Hg, Cd, Pb, Cu, Zn, Cr, Ni, Mn) and chlo roorganic substances (gamma-HCH, Sigma DDT, PCB) in surface sediments of th e Western and the Eastern Odra River was analyzed after the 1997 flood and compared with data from 1995. The research has shown that, like in 1995, the Western Odra sediments were more contaminated with heavy metals and PCBs than the Eastern Odra ones. In comparison with the state of 1995, after the flood in both arms of the O dra, the amount of Cr, Mn, and PCBs has increased while the amount of Pb co ncentration decreased. The levels of Cd, Zn, and Ni have remained unchanged . The changes of the other pollutants were not so clear. The concentration of Hg and Cu increased in the Western Odra, while it decreased in the Eastern Odra; changes of gamma-HCH and Sigma DDT content were inverted.