Floodplains are places of accumulation and secondary release of metals. The polluted water sediments which are stable during normal river flows can erode in the times of floodings and high water stages. In such periods, the pollution of the bad sediments, river waters and the floodplains increases. In environmental research, determining the total metal content does not provide information about their mobility or availability. The toxic effects depend on their chemical form. In this paper, single extraction procedures have been used to determine the forms of easily available metals. Three types of extractants have been used: neutral salt solution (0.01M calcium chloride), mineral acid solution (0.1M chydrochloric acid) and complexing reagents (0.02M ethylenediaminetetraacetic acid (EDTA) and 0.005M deiethylene triamine pentaacetic acid (DTPA)), to determine the extraction effectiveness. The study presents the results of preliminary research of pollution with selected metals (cadmium, chrome, copper, nickel, lead, zinc, iron and manganese) of the Middle Odra Valley. Higher total concentraions of metals were found in the areas currently flooded by the Oder River.
The paper discusses the key issues associated with the location of harbours near the river mouths and the pollution of harbour sediments with heavy metals (e.g. zinc, copper, nickel and lead) and organic derivatives of tin, using the examples of the Gdańsk and Klaipeda harbours. The authors have described the key location factors of the two harbours which largely determine sedimentation processes. It has been shown that the heavy metals content in the sediments of the two harbours does not exceed the concentration values permitted by Polish or Lithuanian law.