Investigation of soil heavy metals concentrations (As, Cd, Co, Cr and Ni) in region Dehnov Shandiz

Heavy metals contamination of soils is one of the main environmental problems. Heavy metals are considered as one most dangerous groups of pollutants because of their toxicity and stability. The biological and ecological importance of heavy metals is due to their characteristics of polluting, their toxicity, persistence and bioaccumulation. The aim of this study was to investigate the spatial distribution of heavy metals in region Dehnow Shandiz (North West of mashhad).

In the present study, 20 soil samples (10-30 cm depth) collected and total concentration of As, Cd, Co, Cr and Ni were measured using Atomic absorption spectrophotometer device. Also, some other soil properties including PH, Organic carbon, CEC and soil texture proportions were measured.

The results showed that the average concentrations of As, Cd, Co, Cr and Ni in the study area were 10.87, 0.26, 14.8, 56.6 and 68.2 mg/kg respectively. Also the results of statistical analysis showed that the standard deviations of As, Cd, Co, Cr and Ni in the study area were 1.97, 0.16, 1.32, 19.47 and 17.39 respectively.

The results indicate that the average concentration of Ni in the soil of study area were higher than the standard of the Environmental Protection Organization of Iran and As, Cd, Co and Cr were lower than the standard. The presence of serpentinite soils has increased the concentration of nickel in the region.