Spatial Distribution of Arsenic under the Influence of Chemical Fertilizers Using Geostatistics in Eghlid, Fars, Iran

Background & Aims of the Study: The aim of this study is spatial distribution of arsenic (As) under the influence of chemical fertilizers using geostatistics in city of Eghlid, Iran. Materials & Methods: In this descriptive study, spatial distribution of arsenic was randomly investigated in 100 soil samples and its content was measured by ICP-OES. Spatial distribution of As and geostatistics were studied by ArcGIS software. Data distribution normality was performed by Kolmogorov-Smirnov test; and then Pearson correlation coefficient was used for correlation analysis. Results: The mean concentration of As was 1.85 mg/kg in the studied area and its change range was 2.08 mg/kg with the minimum and maximum concentration of 0.90 and 2.98 mg/kg respectively. Since the mean concentration of this element was estimated equal to 5 mg/kg in the world's soil, the mean concentration of As was lower than its global value and higher than the qualitative standard in the studied area. Also, the correlation of As with lead (Pb) was 0.406 which was significant at the level of 99%. Therefore, lead was used as the auxiliary data for As zoning.  The results of the geostatistics, cokriging method showed that the highest precision due to the lower error of RMSE and RMSS (RMSE = 0.001, RMSS = 1.052), and thus map of spatial distribution of As was provided on this basis. Conclusions: Results indicated that the dense agricultural soils located in the center of studied area had the highest concentration of As, but the northwestern poor agricultural soils had the highest concentration of As in studied area.