Document Type : Original Articles
Authors
1
M.Sc. student of Soil Science, Faculty of Agricultural Engineering and Technology, University of Tehran, Karaj
2
Associate Professor, Department of Soil Science, Faculty of Agricultural Engineering and Technology, University of Tehran, Karaj
3
Professor, Department of Soil Science, Faculty of Agricultural Engineering and Technology, University of Tehran, Karaj
Abstract
Industry and road traffic, the main causes of environmental pollution in Tehran city, have been growing in recent decades. This study was conducted to investigate the situation of soil heavy metals in Tehran, and Chitgar Forest Park and surrounding land were chosen as the study area. Soil was sampled at 116 sites using a squared grid sampling strategy with a distance of 250 meters. The total concentration of seven heavy metals: lead, nickel, cadmium, zinc, iron, manganese and copper, were measured and analyzed by geostatistical techniques in GIS and GS+ software. The results of variogram analysis and a study of generated maps revealed that spatial variations of metal cadmium, zinc, lead, nickel, manganese and copper in soils were affected by industrial activity. Among all metals, cadmium, with the highest value of Nugget to sill ratio (71%), narrow range of 800 meters and variation coefficient of 0.59, was more affected by industrial activity than other elements. By contrast, total iron concentration, with a wide range of 2638 meters and a very low variation coefficient (0.14), was less affected by anthropogenic activity, suggesting that its distribution is controlled by parent materials. With respect to the total amount of global indices, no heavy metal reached a toxic level, but the indices were clearly affected by industrial activity in the area. This indicates a warning about the risk of toxicity in the future and, therefore, this should be considered in urban and industrial planning and management.
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