ASSESSMENT OF THE CONTENT OF MOBILE FORMS OF HEAVY METALS IN AGRICULTURAL SOILS OF DENISOVKA DISTRICT (KOSTANAY REGION) USING THE ICP-OES METHOD

Abstract

Based on the determination of the content of mobile forms of elements by inductively coupled plasma optical emission spectrometry (ICP-OES), the geochemical and ecological state of agricultural soils in the Denisovska district of the Kostanay region of the Republic of Kazakhstan is assessed, including the study of the content of mobile forms of heavy metals in their ploughed horizon. The study analyzed 38 mixed samples of 0-25 cm of soil layer selected on approximately 932 hectares of agricultural land. The content of Zn, Cd, Pb, Ni, Cr, Fe and As metalloid was determined. The main indicators of descriptive statistics, including the average values of concentrations, the range of content of elements and the coefficient of variation, are calculated, which makes it possible to assess the degree of variability of their distribution in the soil. Average concentration of elements: As – 0.176 mg/kg, Zn – 0.662 mg/kg, Cd – 0.042 mg/kg, Pb – 0.253 mg/kg, Ni – 3.357 mg/kg, Cr – 0.357 mg/kg, Fe – 25.89 mg/kg. Comparison of the results obtained with the maximum permissible concentration standards showed that the content of mobile forms of heavy metals does not exceed the established sanitary and hygienic standards; for As, Pb, and Cd, which are regulated only for total content, the comparison is indicative. The obtained data testify to the favorable geochemical state of agricultural soils of the studied territory, can serve as background indicators for steppe soils of Northern Kazakhstan and can be used as a basis for regional environmental monitoring.