Investigation of enrichment, toxicity and ecological risk of heavy metals in Bahmanshir River surface sediments

In recent years, metal contamination in the aquatic environment has attracted global attention owing to its environmental toxicity, abundance and persistence. This study was carried out to determine the concentration, origin and toxicity of heavy metals (Fe,Mn,As,Ni,Pb,Zn,Cu,Cr) in surface sediments of Bahmanshir River.14 surface sediment samples (0-10 cm) were collected using a grab sampler. Concentration of heavy metals was measured using ICP-OES method. Physico-chemical parameters (pH, Organic Matter (OM)) of sediment were determined by standard methods. In order to assess sediment contamination to heavy metals, different indices, Enrichment Factor, Potential acute toxicity and Ecological risk were calculated. The results showed moderate contamination of sediment with metals of Ni and Cr ºand low risk level of sediments. The Statistical analysis showed that metals Pb,Zn,Cu,Cr may have originated from anthropogenic sources ; As can originate from natural process and Ni seems to have both natural and anthropogenic sources.