Szukana fraza: [Abstract = "Fractionation of Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn has been performed in bottom sediment samples collected along a 75 km section of the middle Odra River by a modified method of 5\-step sequential extraction according to Tessier. The results have shown the presence of Cu, Ni, Zn and Mn already in exchange fraction \(I\)."]