Ecological Assessment of Concentrations of Heavy Metals and Arsenic in Soils and Crops of the Central Chernozemic Region

The ecological assessment of the contents of Cr, Pb, Cd, Hg, and As in arable soils and crops grown in the central chernozemic region of Russia was carried out by the example of Belgorod oblast. It was found that average bulk contents of Cr, Pb, As, Cd, and Hg in leached arable chernozem were 19.8, 10.0, 4.15, 0.22, and 0.021 mg/kg; in typical arable chernozems, 20.0, 10.3, 4.18, 0.23, and 0.022 mg/kg; and in ordinary chernozems 20.9, 11.2, 5.48, 0.35, and 0.023 mg/kg, respectively. The average contents of mobile forms of Pb, Cr, and Cd were 0.52, 0.14, and 0.06 mg/kg in leached arable chernozems; 0.46, 0.13, and 0.05 mg/ka in typical arable chernozems; and 0.55, 0.13, and 0.04 mg/kg in ordinary chernozems, respectively. These elements did not exceed the established maximum permissible concentrations (MPCs) and tentative permissible concentrations (TPCs) for the studied soils. Organic fertilizers were found to be the main source of heavy metals in the arable soils of Belgorod oblast. Average concentrations of Cr, Pb, As, Cd, and Hg in cattle manure were 0.90, 0.78, 0.277, 0.060, and 0.0084 mg/kg, respectively. Among studied crops, sunflower seeds had the highest concentrations of Cd, Pb, and Cr, while winter wheat grains had the highest concentrations of Hg and As. Soybeans contained the lowest average contents of Pb, Hg, and As, and the corn grain had the lowest average contents of Cr, Cd, and As. In the grains of winter wheat, corn, soybeans, and sunflower seeds, the contents of Pb, Cd, Hg, and As did not exceed MPCs established for products intended for food purposes, and the concentration of Cr did not exceed the MPC established for feed.