Pollution intensity of nickel in agricultural soil of Hamedan region

In the recent years, agricultural soils have received more chemicals in various forms for higher yields. This may result in the accumulation of metals in soils which subsequently may be transferred into the agricultural crops. In the present investigation, nickel content of 58 composite soil samples and also agricultural crops, is studied. Ni in samples of soil and agricultural products were extracted and determined using atomic absorption spectrometer. The spatial distribution map of Ni was drawn using Kriging method. Mean concentration of nickel in the soil of the study area is about 62 mg.kg-1. It was also found that among the harvested crops, corn has a higher concentration of nickel than the standard limit. According to chemical fractionation results of nickel in soil, anthropogenic and natural shares of this metal are 19%, and 81% of the bulk concentration, respectively. Results of comparison of heavy metal pollution intensity in the agricultural soil by Igeo index as well as IPOLL index showed that Ni is in the non-polluted to moderately polluted class. Analysis of zoning map of pollution index showed that Ni is mainly of geological sources.