عنوان مقاله [English]
The investigation on toxic elements in sediments around the Chahar Gonbad copper-gold mine indicates sediments with various sources of pollution. In order to investigate the source and chemical fractionation of toxic elements 38 sediment samples were collected from 0 to 5 cm depth of river, alluvium and dam sediments randomly. The average values of elements in sediments are: 0.09 ppm Ag, 17.82 ppm As, 0.48 ppm Bi, 0.22 ppm Cd, 17.58 ppm Co, 91.49 ppm Cu, 43161.33 ppm Fe, 1152.83 ppm Mn, 0.97 ppm Mo, 41.5 ppm Ni, 10.82 ppm Pb, 484 ppm S, 1.3 ppm Sb, 0.13 ppm Se, 1.05 ppm Sn, 3067.67 ppm Ti, 0.35 ppm Tl, 126.5 ppm V and 90.82 ppm Zn, respectively. The average values for waste dam sediments include 0.22 ppm Ag, 28.37 ppm As, 13.14 ppm Bi, 0.26 ppm Cd, 51.88 ppm Co, 1981.4 ppm Cu, 81677.33 ppm Fe, 2165.13 ppm Mn, 72.86 ppm Mo, 80.67 ppm Ni, 191.38 ppm Pb, 5593.17 ppm S, 47.75 ppm Sb, 0.66 ppm Se, 1.77 ppm Sn, 2136.83 ppm Ti, 0.43 ppm Tl, 80.75 ppm V and 989.94 ppm Zn. The obtained results were evaluated by using of multivariation statistical method including correlation coefficient, principal component analysis (PCA), and cluster analysis (CA). By using a multivariation statistical method it becomes obvious that the sediments can be divided into four different categories. The first category of these sediments are derived from mining activity, which in the first component of the PCA analysis are related to Ag, As, Cd, Co, Cu, Fe, Mo, Pb, Sb, Se, Sn, Tl and Zn. The second category of sediments are not affected by mineralization and in the second component of PCA analysis are indicated by Al, Sc, Sr, V, Ta, Ti. The third category is of natural sediments, on which, rock source and mineralization had an influence, thus include the third component of PCA analysis and are indicated by Bi, Mn, and S. The forth category of sediments include toxic elements such as Cr and Ni that either are derived from weathering of sulfides or probably from ophiolitic rocks.