ASSESSMENT OF HEAVY METAL POLLUTION IN SITNICA RIVER SEDIMENT

Being essential and integral parts of water systems, sediments used to provide the substrate for organisms and through interaction with the overlying waters play an essential role in the aquatic ecosystem. Natural environment which is polluting by heavy elements is considered as a universal problem. The heavy metals released in the environment as the result of human activities, atmospheric depositions and erosions would finally enter in to the aqua systems. This work contributes to the monitoring of sediment pollution in Sitnica River district by assessing the degree of pollution in the surface sediment. Since, heavy metals are toxic, stable in the environment and potential to combine with the nutritive continuum. Thus, they are considered as one of the most significant pollutant in aqua systems. The surface layer of sediment is chosen where this layer controls the exchange of metals between sediments and water most. The primary goal of the study is to determine the concentration of Pb, Cd, Cu and Zn in surface sediments which act as contamination indicators. Samples were collected twice a month between January and December 2013 from 6 sites along the River Sitnica. The concentration of these elements was determined by using Atomic Absorption Spectroscopy (AAS). All the determined parameters with AAS were compared with the results of ICP/OES method. Concentrations of metals generally decreased with distance downstream, with highest values occurring in the industrial upper stream of Sitnica River. Concentrations of cadmium, copper, and zinc in 2013 were lower at most sites than those in previous years. Unlike, the lead and cadmium concentration were generally higher in 2013. The most probably reasons of these results may be the influence of thermal power plants at Obiliq, located very close to Sitnicar River.