Progress of Cryogenics and Isotopes Separation , ISSN: 1582-2575
2019, Volume 22, Issue 1
Pages 77-90

Distribution of heavy metals in water and sediments from lakes of the Olt watershed

Abstract

Knowledge on heavy metals accumulation level from surrounding sources around a watershed is of fundamental concern to mitigate the impact of anthropogenic activities on water ecosystems. Therefore, eight heavy metals with toxic potential and their accumulation in surface water and sediments, sampled in 22 lakes/dams along the Olt River (Romania), were investigated in this work. To compare the total content of metals at the sampling locations a metal pollution index (MPI) was calculated and the level of partitioning the metals between the surface water and sediments in the area was assessed using partition coefficients (Kd) between the metal pairs in both media. MPI in water varied from excellent quality at sampling point Dragasani Lake to very high degree of pollution at Govora Lake (situated in close proximity of a chemical platform), while in sediment was found from low degree of pollution at Arcesti Lake to extremely high degree of pollution at Ramnicu Valcea Lake. The higher values (log Kd >1) recorded for Cr, Cd, As, and Hg imply low solubility and greater retention of these metals on the sediment and the lower log Kd values recorded for Cu, Zn, Pb, Ni suggest lower affinity of organic sediments to adsorb metals. In sediment samples the “strong” correlations were found for the following pairs of metals: Cu-Zn (r=0.89), Ni-Zn (r=0.80), Cd-Zn (r=0.77), Ni-Cr (r=0.76), Ni-Cu (r=0.95), Cd-Cu (r=0.78), Cd-Ni (r=0.77) and Cd-Pb (r=0.96); in water samples the “strong” correlations were found for Ni-Cr (r=0.92), Pb-As (r=0.77), Ni-As (r=0.77) and Ni-Pb (r=0.76).

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