Physico-Chemical Parameters Determining the Variability of Actually and Potentially Available Fractions of Heavy Metals in Fluvial Sediments of the Middle Odra River

The occurrence of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn) has been determined in the fluvial sediment samples collected along three transects in the Middle Odra River (western Poland) with a width of 360 m. The total concentrations of the metals were obtained after HNO3 microwave digestion and the available fractions of heavy metals were determined by single extraction procedures using two extractants: 0.01M CaCl2 and 0.05M EDTA. The measurement of physico-chemical parameters was also performed. The determination of total and available fractions of heavy metals, except potential available fractions of Cr, revealed high concentrations of studied elements detected in the sediment samples characterized by high content of coarse and very coarse-grained sand fraction and high content of organic matter. It was found that the concentrations of total and available fractions of metals could increase along with the content of organic matter, Eh values and concentrations of H+. Apart from the above, those concentrations become the lowest, the higher the content of medium grain size fractions is. Furthermore, the amounts of CaCl2 and EDTA extractable metals increase in the sediments samples characterized by the lowest total and available concentrations of heavy metals

Preliminary study of heavy metal pollution in the floodplain sediments of the Lubusz Oder Gap

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