Monitoring of Chrome and Nickel Contents in Agroecosystems of the Central Chernozem Region of Russia

This study was performed under the state agroecological monitoring program. The purpose of this work is to conduct an environmental assessment of the contents of chromium and nickel in the agroecosystems of the southwestern part of the Central Chernozem region (CChR) from the example of Belgorod oblast. All analytical studies were carried out in the accredited testing laboratory by generally accepted methods. During this study, it was established that the average total Cr and Ni contents in the arable layer in leached chernozems are 19.8 and 24.5; in typical chernozems, 20.0 and 24.9; and in ordinary chernozems, 20.9 and 26.6 mg/kg, respectively. The average contents of mobile forms of chromium and nickel in the studied soils range within 0.13–0.14 and 0.37–0.41 mg/kg, respectively. The levels of the approximate permissible concentration of nickel and the maximum permissible concentration of mobile forms of these heavy metals in soils are not exceeded. In the agroecosystems of Belgorod oblast, Cr and Ni are mainly supplied with organic fertilizers, but this does not pose a risk for soil contamination and crop products. The highest average chromium content (0.45 mg/kg) is observed in sunflower seeds, and the lowest (0.22 mg/kg) is in corn grain. Soybeans are characterized by an anomalously high nickel content (4.81 mg/kg), and the lowest concentration (0.63 mg/kg) is recorded in corn kernels.