Increasing agricultural activities giving rise to pollutants is one of the today’s man serious and expanding problems. Due to accumulation of heavy metals in soil and its risk to human health, their recognition, origin and distribution have attracted considerable interest in recent years. There is no information available on the distribution pattern of heavy metals concentration in soils of Hamadan province. The purpose of this research was to determine the spatial distribution of Zn, Pb, Ni and Cd in surface soil of Hamadan province. Ussing justify; LINE-HEIGHT: normal; MARGIN: 0in 0in 0pt; unicode-bidi: embed; DIRECTION: ltr; VERTICAL-ALIGN: top" For heavy metals concentrations maps, total Zn and total Ni, we used ordinary kriging and exponential models, total Cd and total Pb disjunctive kriging and Spherical models and available Zn ordinary kriging and Spherical model. Analyzing the metals concentration distribution maps and overlay of soil heavy metals spatial distribution, geology and land use maps were shown that Zn, Pb and Cd concentrations depends to geology and agriculture and Ni concentration depends to geology. However, agricultural activities due to excessive consumption of chemical fertilizers can increase these further elements to the soil. High correlation between parent material origin elements and some soil properties such as sand, clay and Cation Exchange Capacity were. While zinc and lead not showed a high correlation with these characteristics. Distribution of measured metal concentrations showed that Based on standard infection Netherlands, Ni has the highest contamination, About 97 percent of samples excess of the Netherlands limit value, While the concentration of Zn, Pb and Cd exceeded the Netherlands’ guidelines in 1.05 , 0.35 and 0.35 percent of the study samples respectively. The results of this study indicated that selected heavy metals (Ni and Pb)have parent materials origin and agricultural activities contributed to accumulation of Zn and Cd in agricultural land. Also study of spatial distribution of heavy metals showed that the highest concentration of heavy metals in the soils of studied region corresponds to sandstone, limestone, shale, metamorphic and igneous bed rocks
