Spatial distribution of copper and other elements in the soils around the Sarcheshmeh copper smelter in southeastern Iran

Abstract

Anthropogenic activities such as mining, metal extraction from ores and smelting are important sources of environmental pollution with toxic elements. Knowing the spatial distribution of soil pollution around these sources is important for dealing with the risk situation. The objective of this study was to determine factors and processes dominating the spatial distribution of copper (Cu), and a variety of other elements, in particular lead (Pb), zinc (Zn), chromium (Cr), nickel (Ni), and (As), in the soils around the Sarcheshmeh smelter, which is the largest Cu smelter in Iran. Topsoil (0–15 cm) samples were collected from 100 locations covering a large area around the smelter and analyzed the above and other elements, basic soil properties and topographic attributes for each sampling location. The concentrations of soil Cu, Pb and Zn were highly elevated around the smelter and showed clear trends for 7–8 km (Pb and Zn) and more than 10 km (Cu) to decrease with distance from the smelter, in contrast to As, Cr and Ni. Only a narrow zone of locally increased concentrations around the smelter was still found for As, while Cr and Ni showed no significant relationship to the location of the smelter at all. After accounting for the distance to the smelter, the soil factors explained very little variance in the spatial distributions of these elements and the topographic variables none at all. The results indicate that (a) emissions from recent mining and smelting activities and dispersal through atmospheric transport were the main source for soil pollution by Cu, Pb and Zn in the region, (b) soil Cr and Ni distribution patterns are due to local geogenic origin, (c) and the areal distribution of soil As represents a mixed pattern of predominantly geogenic sources with an additional contribution from pollution in the vicinity of the smelting and mining activities. We conclude that strict control of emissions into the atmosphere from the smelter and the mining area is necessary to avoid further increase of soil metal pollution in the study region.