Heavy Metals and Quality Index Monitoring in the Sediment of Kalan Dam, Malayer

Sediments are the most important sources in the study of aquatic ecosystems. Bottom marine sediments are sensitive indicators for monitoring pollutants as they act as a sink and a carrier for contaminations in aquatic environment. The objective of this research was to evaluate the degree of heavy metal contamination in Kalan Malayer dam and the extent of sediment quality according to three indices. In this study, heavy metals such as As, Cd, Cu, Cr, Mn, Hg, Ni and Zn in 12 station were measured of lake bed sediments. Then, sediment quality was analyzed by calculating of geo-accumulation index, pollution index and enrichment factor. The highest amount of pollution index respectively belonged to As (2.520), Ni (1.225) and Hg (1.138). The results obtained from pollution index, geo-accumulation index and enrichment factor indicated that the As, Ni and Hg were high in 9 to 12 stations. Multivariate principal component analysis (PCA) was performed on the indices data, and two components were extracted which explain 85% of the total variance, and the eigenvalues >1. All heavy metals (except Mn) had positive coefficients with each other. The stations 9 to 12 were located near agricultural farms and the high concentration of some heavy metals in these stations can be due to human and natural resources such as excessive use of agricultural field, the intensive use of pesticides and the entrance of chemical fertilizers aquifers.