Assessment of heavy metals contamination (Arsenic, Cadmium and Lead) of agricultural surface soil around Zahab Zone (Kermanshah)

Intense urbanization, large scale industrialization and unprecedented population growth in the last few decades have been responsible for lowering environmental quality. Soil contamination with metals is a serious concern due to their toxicity and ability to accumulate in the biota. This study were done to evaluate the concentrations of metals such as Arsenic, Cadmium and Lead in superficial soils of agricultural land around Zahab zone as well to map concentration spatial distribution. The sampling points were recorded by GIS and then imported to the GPS. The soil samples were collected from the surface layer(0–30 cm) of soil .The samples were transported to the laboratory and soil preparation were done. Total concentrations of As, Cd and Pb were analyzed by Atomic Absorption Spectrophotometer (SHIMADZU-AA-6300). The chemical and physical parameters of the soil such as clay, silt, sand, organic matter, lime, EC and pH were also measured. Data distribution normality were assessed using the Kolmogorov - Smirnoff normality test (K-Sp). All data were normally distributed with the exception of EC. EC was normalized by logarithmic transformation. Pearson correlation test showed that there are significant correlations between As with EC (P < 0.01)and organic matter (P < 0.05). Concentrations comparison with international standards showed that these metals are in good condition. Contamination factor showed that Pb is more contaminated than the other two metals(Moderate Contamination ,53.13%). The low concentration of the metals in Zahab zone is due to traditional and small scale farming because farmers could not apply chemical fertilizers so they used mostly manure in their farms. As a result, the produced metals by agricultural activities do not pose a threat to crops and also environment.