Heavy metals in recent alluvium of the Odra River

Abstract

Together with its tributaries, the Odra River is a receiver of huge amount of industrial waste water produced in territories of Poland, the Czech Republic, and Germany in connection with (among others) extraction of mineral raw materials and operation of metallurgical and coking industries as well as many other industrial plants. Municipal sewage from cities situated on the river are also disposed to the Odra River. A huge amount of dissolved salts is not the only load transported by the waste water; also, a large amount of heavy metals is other load being brought to the Odra water. As a result of self-purification process of the river, a considerable portion of these metals is subject to accumulation in the river bottom deposits. As a total, 153 samples of alluvial sediments were collected for laboratory determinations; they were collected at a distance of each 5 km along the Odra course. Additional samples (115 in total number) were collected from the Odra tributaries, from sampling points located near each tributary’s confluence to the Odra. Grain size fraction < 0.2 mm was used to determine concentrations of Ag, Cd, Cu, Cr, Co, Ni, Pb, and Zn. The Inductively Coupled Plasma Atomic Emission Spectrometry was employed to make these determinations. The content of Hg was measured using the Cold Vapour Atomic Absorption Spectrometry. Heavy metals in alluvium of the upper and middle Odra tracts covered by this study occur in concentrations exceeding many times the geochemical back-ground values for particular elements. On the contrary, alluvium in the lower Odra course (downstream from the confluence of the Warta River) contains markedly less concentrations of heavy metals, in general near their geochemical background. High concentrations of Cu, Hg, Pb, and Zn characterise alluvium of the upper and middle Odra. Accumulation of these metals in the Odra alluvium is visibly under the influence of mine water disposal practised by hard coal (bar) mining zinc-lead ore mining and metallurgy (zinc and lead), copper ore mining and metallurgy (copper, lead, and zinc), and the production of effluents in chemical plants (mercury).