Geochemical and Environmental Assessment of the Heavy Metals in Robat Sefid Rigion (south of mashhad) Soil

Robat sefid region located in mashhad to torbat road and surrounded with ophiolite outcrop serpentine formation that could be mentioned as source of Lithogenic contamination. Considering importance of this matter, in this paper heavy metal studying and evaluation have been done in soil sources of robat sefid region. So heavy metal density in 11 soil samples have been studied and interoperated. For this aim multivariate statistical methods and index of geoaccumulation, enrichment factor, contamination factor and modified degree of contamination have been used. Correlations between elements have been evaluated with multivariate statistical methods (Pearson Correlation, Cluster Analysis and principle component analysis). Based on evaluations, ophiolite rocks (Serpentine، Gabbro، Dunite and Harzburgite) has been considered as Lithogenic source of elements in region. Based on index of geoaccumulation measurement for soil, Nicole has the highest rate of contamination in this region. Enrichment factor calculation shows that Nicole and Chromo have very high contamination and Cobalt has high contamination in this region. Also contamination factor measurement shows severe enrichment of Nicole in this region but region geology structures and ophiolite rocks weathering are the entrance source of these heavy metals and have Lithogenic source.