Concentration of Heavy Metals in Irrigated Soils in Southern Kazakhstan

Abstract

Currently, one major negative factor in the reduction of soil fertility is contamination with heavy metals, pesticides and other pollutants. In this regard, the main purpose of this work is to study and evaluate soil pollution with heavy metals in irrigated areas of Southern Kazakhstan and to determine the key geochemical parameters of heavy metals. One research object was the soils of large rice farms in the Shiely area of irrigation. The study was conducted using the method of large-scale soil analysis and mapping. Among the environmentally hazardous mobile forms of metals in the soils of the Shiely irrigation area, Pb has the largest share (54 %), then Ni (22 %). Zn and Cu have 12 and 10 % respectively. The share of Cd is only 2 %. Based on the analysis of cartographic material, it has been determined that on the territory investigated, Cu is found in 5 groups of soil which contain more than 3.15 mg Cu per 1 kg of soil. A high concentration of Pb is found in the group of soils, at 9.0–15 mg per 1 kg of soil. Ni is found in high concentration in soils: 4.6–6.0 mg/kg. Thus, based on analysis of the data obtained, we can conclude that for all the mobile forms of the elements studied, one major aspect is the predominance of the accumulative character of distribution in the soil profile is observed, and gross forms are characterized by eluvial-illuvial processes. Environmentally hazardous mobile metal forms available for the plants are subjected to the influence of irrigation to a greater degree than their gross forms.