CONTAMINATION STATUS OF ERZENI RIVER, ALBANIA DUE TO HEAVY METALS SPATIAL AND TEMPORAL DISTRIBUTION

Heavy metals are considered as serious pollutants of aquatic ecosystems because of their environmental persistence, toxic potential and ability to be incorporated into the food chain. In the present investigation, the contamination status of one section of Erzeni River was assessed in regard to occurrence and distribution of some heavy metals. Due to concerns about potential pollution resulting from watershed sources and adjacent increased human activities, the study was performed at a representative section of this river, during the period December 2013-April 2014. The filterable fraction of heavy metals such as Pb, Cu, Cd, Zn and Ni was determined using the GF-AAS technique. BGBI.II, Nr. 96/2006 as well as 2008/105/EC Directives were used for the estimation of the contamination status of the river water. Distribution of heavy metals in the river water was also evaluated by means of the Contamination Index (CI) and the Mean Contamination Index (MCI), values. The relative abundance of heavy metals followed the order: Zn>Ni>Pb>Cu>Cd, while probability plots ([alpha] = 0.05) confirm that external pressures can contribute to heavy metal levels in waters of Erzeni River. Although CI varied evidently in different sites, assuming that the levels of heavy metals are very dependent with location, the MCI values prove that there exist a high degree of spatial and temporal homogeneity at all scales due to a high rate of water mixing in the river.