Agricultural soil contamination and degradation near a mining area in an arid region

Abstract

Industrial and mining activities release toxic substances and heavy metals into the soil of the surrounding environment and result in soil degradation and desertification. The contaminated residential areas near mines can endanger the health of residents, and the agricultural lands at the fringes of mines contaminate agricultural products with heavy metals. In this study, in order to determine the rate of soil degradation and its contamination at the margins of Koushk Pb-Zn mine, the surface of the agricultural soil adjacent to the mine was sampled. Surface soil samples were also prepared from around two villages in the vicinity of the mine and along the roadside. The samples were digested using four acid methods and analyzed by ICP-OES, and the concentrations of Pb, Zn, Cr, Co, Sb, and Ba were measured in the samples. The difference between the concentrations of heavy metals in the agricultural and rangeland soil samples was assessed with a t-test, and the corresponding contamination maps were plotted. The results showed that the agricultural soil in both villages was more polluted than the rangeland soil around the villages. Indeed, the lead and zinc concentrations in the agricultural soil of Koushk were several times higher than environmental standards. Also, despite the equal distance of the villages from the mine, the average amounts of barium, lead, and zinc in Koushk soil were 1.5, 26, and 11 times higher than those in Seyyedabad, respectively. As a result, the parent materials geochemistry is a major source of variation in soil pollution in two villages. In addition the agriculture management style can play a role in elemental content of the samples.