Evaluation of the possibility of using normalization with cobalt in detection of anthropogenic heavy metals in sediments

Geochemical normalization with conservative elements has been effectively used for assessing the enrichment of metal pollutants and distinguishing their natural and anthropogenic sources. Without correcting for textural and mineralogical variability, a comparison of heavy metal data with regional background is complicated because of large variablity due to irregular grain size and sediment composition. The normalization with cobalt in the enrichment factor calculation presents a new approach in detection of anthropogenic elements in sediments. In present study, the heavy metal concentrations (Cd, Cu, Fe, Mn, Cr, Ni, Pb, V and Zn) were determined in the river sediments of 35 rivers in Serbia. The enrichment factor (EF) was used to estimate the anthropogenic heavy metals input as well as to make a quantification of the metal enrichment degree. Different research sources recommend the use of Fe, Li, Al and Si as conservative elements. Within the scope of this research the cobalt was selected as the element for the normalization. It was observed that the cobalt concentration is not higher than the regional background concentration, which is similar to the average concentration of this element in the continental crust. The positive correlation between Cd, Cr, Fe, Ni, Pb, V, Mn and Zn with Co suggests that it could therefore be a suitable normalizing element in EF calculations for the studied river sediments. The anthropogenic influence of heavy metal pollution could be traced by the use of such EF values, and the values for the studied river systems are presented