Geo-statistical Distribution of Heavy Metals in Karoon River’s Soil by Geographic Information System

Introduction: Soil has an important role in nutrient cycle and an important function in storage, refinement, and movement of nutrients for the living and non-living parts. Soil pollution of heavy metals and elements is one of the common pollution impacts of human activities, especially industry. Realization of distribution pattern of these elements and their anthropogenic sources is a major part of environmental protection plans. In the present study, concentration of two major heavy metals were investigated and mapped using geostatistical methods throughout western part of Karoon   river in Ahwaz city. Four land areas including urban areas, agricultural, industrial, and bare soils were applied. Materials and Methods: In this research, at first, 40 sample plots were determined randomly from the study area and soil samples were taken from surface layer with the depth of 20 centimeters. Afterwards, the data were entered into SAS 9.3 and Arc GIS 10.2 applications for data analysis and mapping. Results: Results showed that Pb and Cd concentrations had the lowest standard rate in western parts of city while their highest rate was in river shores, south-west, and northern parts. Hence, the soil is over polluted in these areas comparing to WHO standards. Conclusion: A significant correlation was observed between Pb and Cd elements. Regarding results achieved by the semi-variance model, it is concluded that pollutions have anthropogenic sources in this area. According to the results, most important factors of pollution in this area were smelting and steel factories as well as agricultural pesticides.