Effects of Land Use on the Concentrations of Some Heavy Metals in Soils of Golestan Province, Iran

Soil contamination significantly reduces environmental quality and affects human health. To investigate and assess the effects of land use on the concentrations of some heavy metals in surface soils of Golestan province, 227 soil samples (0-60 cm) were collected from three types of land uses including agricultural lands, natural, and industrial areas. The total metals and metalloids (Cr, Se, As, Cd, Ni, Pb, Zn, Cu, Fe) were extracted and their concentrations were measured in all samples. The results showed that heavy metals accumulations in soil samples of the industrial land uses were higher than agricultural and natural land uses. There was significant correlation among the soils heavy metals (more than 30% for most samples) and also between soil heavy metals and organic carbon content in different types of land uses (average of 40%). Cluster analysis revealed that As and Se had the highest concentration values compared to their corresponding background in most samples and showed the evidence of anthropic effects. Various indices including pollution load index (PLI), modified contamination degree (mCd), and enrichment factor (EF) were used to determine the soil contamination level. The results of PLI and mCd,indicated the higher accumulation of heavy metals at industrial land uses. The enrichment factor of Se and As in soils were higher than the other metals, however, their values showed that anthropogenic activities had not serious effects on the environment quality in the studied area.