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

Abstract

Soil contamination significantly reduces environmen tal quality and affects human health. To investigate and assess the effects of la nd 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 a gricultural 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 i ndustrial land uses were higher than agricultural and natural land uses. There was signi ficant correlation among the soils heavy metals (more than 30% for most samples) and also between soil heavy meta ls and organic carbon content in different types of land u ses (average of 40% ). Cluster analysis revealed that As and Se had the highest concentrati on 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 (mC d ), and enrichment factor (EF) were used to determin e the soil contamination level. The results of PLI and mC d , indicated the higher accumulation of heavy metals a t industrial land uses. The enrichment factor of Se a nd As in soils were higher than the other metals, however, their values showed that ant hropogenic activities had not serious effects on the environment quality in the studied a rea. Keywords: Enrichment factor, Modified contamination degree, P ollution load index.