Spatial Variability of Arsenic under Different Land Use in Isfahan Region

Industrial, agricultural and urban activities have contaminated soil by heavy metals that can also increase concentration of the metals in food chains. This study was carried out in Isfahan province where lots of such activities are in progress. The purpose of this study was to determine spatial variability of Arsenic)As) in Isfahan soils. In this research, the soil samples)0-20 cm) were collected in a stratified random sampling system at about 4 Km intervals in a study area of 6800 Km2. The positions of samples were recorded using a GPS. After laboratory preparation, soil samples were measured for total As. Spatial structures of total As were determined by directional variograms. Spherical model was the best model to describe spatial variability of As. Mean-square error)MSE) and correlation coefficient were used to validate variograms. Distribution map for Arsenic was prepared using the obtained information from element by point kriging method and by using Surfer software. Interpolation in blocks by dimensions of 1000×1000 m was made. The mine effective factors with high concentration of As are parent material, and direction of dominant wind has affected the spread of As in north-west of the study area.