Contamination Factor and Comprehensive Pollution Index (A Case Study in Nahavand City)

Any change in the environmental characteristics such that the normal functions and biological balances are disrupted and life of organisms is threatened directly or indirectly is called environmental pollution. The purpose of this study was to determine the contamination with heavy metals Chromium, Copper, Nickel and Zinc in soils of Nahavand city, Hamadan Province using different indicators. A total of 39 soil samples were taken systematically and concentrations of Chromium, Copper, Nickel and Zinc were measured using a spectrophotometer. Geo-accumulation index, contamination actor and Nemero comprehensive pollution index were used to determine the extent of contamination in the study area. Results showed that the Cobalt concentration in the region is at the maximum allowable concentrations based onr other countries. The Geoaccumulation index results showed that the rate of accumulation of the index is between 0 and 1 for all metals. Concentration of heavy metals in soil was related to their natural origin. Contamination factor results showed that most samples were moderately to highly polluted. Contamination factor for Chromium was the highest and 10.26% of the data showed they were moderately to highly polluted. Analysis of interpolation maps of comprehensive pollution index showed that the metals Chromium, Copper, Nickel and Zinc have geological and agricultural origins. These metals are present naturally in soil, but human activity has caused the accumulation of these metals in the soil.