Assessment of ecological risk of soil contamination by heavy metals

Purpose. To assess the ecological risk of soil contamination by heavy metals and analyze their concentrations in protected areas in the Zmiivska community of the Kharkiv region and the impact zone of the Zmiivska TPP. Methods. Field techniques, atomic absorption spectrophotometry; Hakanson methodology was applied to evaluate ecological risks, including the calculation of contamination factors (Cif), potential ecological risk indices (Eir), and the total risk index (RI). Results. The study involved soil sampling from four locations: the botanical reserves "Tsykalove," "Mokhnachanskyi," "Skrypaivskyi," and the area near the Zmiivska TPP. The concentrations of heavy metals in soils from the protected areas (reserves "Tsykalove," "Mokhnachanskyi," and "Skrypaivskyi") did not exceed permissible levels, except for elevated zinc and iron content. In the soils near the Zmiivska TPP, significant exceedances of background levels were observed: iron, copper, cobalt and zinc. The total risk indices (RI < 4) for protected areas indicated low ecological risk: "Tsykalove", "Mokhnachanskyi", and "Skrypaivskyi". However, the Zmiivska TPP area (RI = 25,98) demonstrated a much higher risk. The highest potential risk indices (Eir) were associated with cobalt and cadmium. Conclusions. Soil contamination by heavy metals in the Zmiivska community is localized, with the most hazardous concentrations observed near the Zmiivska TPP. The protected areas exhibit minor contamination risks, although high bioavailability of zinc and other metals indicates the need for continuous monitoring. The Hakanson methodology proved effective in evaluating health risks associated with heavy metal exposure. These findings highlight the necessity of mitigation measures, including emissions control, soil remediation, and reduced anthropogenic pressure.