Spatial Variability and Mappingofthe Total Concentration of Iron, Zinc, Copper and Manganese by Using Geostatistical Method in Southern Tehran Soils

This study was conducted to evaluate the performance of kriging and inverse distance weighting (IDW) estimators for determination of spatial variability and mapping of iron, zinc, copper and manganese heavy metals in 196 points of surface soil(0-30cm) with a distance of 1000 m in 20,000 hectares of Southern area of Tehran. The best models for iron and manganese were exponential and spherical for zinc and copper. For determining the accuracy of estimator, Jack Knife technique, the mean error (ME) and root mean square error of prediction (RMSE) were evaluated. For estimating the inverse distance weighting (IDW) the powers of 1 to 5 were used. The contents of ME and RMSE in kriging were less than the IDW for four elements. The results showed that the total average concentrations of iron, zinc, copper and manganese, respectively were 29.37 g.kg-1, 131.2 mg.kg-1, 46.1 mg.kg-1 and 682.6 mg.kg-1`. Manganese and zinc pollution in soils were widespread. Iron and copper levels were below the critical limit. Comparison of the land use map with continuous map of iron, zinc, copper and manganese showed the land use, distance and proximity to the highways, industrial and residential areas and irrigation with wastewater had significant effect on the contents of heavy metals to different extent.