Evaluating the Concentration of Heavy Metals in Downstream Area of Southern Waste Landfill in Kermanshah

Affected by the change of land-use pattern, soil pollution has become an important environmental issue in developed and developing countries.  Heavy element pollution, as a kind of soil pollutant, is really dangerous due to their high toxicity and persistence in the environment. In the current study, the extent of pollution to heavy elements in downstream area of southern waste landfill of Kermanshah city was investigated. In this research, 208 soil samples (from 0 to 20 cm depth), were collected with 50 meters distances systematically from downstream area of waste landfill. The spatial pattern of variables was investigated through calculating experimental variograms and fitted models using geostatistics.  The mean concentrations of Fe, Mn, Cu and Zn in downstream area of waste landfill are 4077, 943, 41.8 and 102 mgkg−1 respectively. The spherical model was recognized as the best model to describe the spatial variability of total heavy metals. Total content of Fe, Mn, Cu and Zn showed a strong spatial dependence. According to the ordinary kriging maps, the total concentration of elements in the central parts of the study area is less than the other parts. This is probably due to the lower slope of the central region and consequently the lower infiltration. The concentration of elements in the southeastern towards the northeast High slope of the area is the result of the adjacency to the waste landfill and also the higher steepness in this part. The findings indicated a long-term progressive trend soil pollution, thus it is necessary to halt latex infiltration either towards the soil or vertically ground water. The results showed a long-term progressive trend in soil pollution. Considering population growth, waste production rate, distance from the city center, and other factors determining the location of landfill, it is suggested to reconsider positioning waste landfill scientifically. Furthermore, some services such as waste separation in the source, waste recycling in the source, and composting would be inevitable.