Spatial Assessment of Heavy Metal Contamination in Agricultural Soils under Wartime Conditions and Perspectives for Organo-Mineral Remediation

Abstract

The article analyzes the extent of soil contamination caused by military activity and justifies approaches to its remediation. The relevance of the study is in the need for a comprehensive examination of the dynamics of changes in the ecological state of the territory subjected to technogenic load and the search for technological solutions for its restoration. The most dangerous phenomenon is the accumulation of heavy metals, which suppresses soil biological activity and worsens its agronomic properties. However, existing methods of soil remediation are ineffective in complex and heterogeneous contamination. The research conducted a comparative assessment of the concentrations of lead, cadmium, and mercury in the contaminated territory of Kalchenkivska village council (Sumy region, Ukraine) using data from 2021 and 2026. A significant increase in lead concentration, from 1.15–2.75 mg/kg in 2021 to 10.8–84.7 mg/kg in 2026, was observed. For cadmium, an increase in content from 0.05–0.09 mg/kg in 2021 to 0.22–1.36 mg/kg in 2026 was also recorded. Mercury in 2021 was below the analytical method’s detection limit, while in 2026 it was detected in various samples, with a maximum value of 0.092 mg/kg. Based on the spatial distribution patterns of heavy metals obtained, the need for remediation measures in the studied area was substantiated. Digestate and sunflower husk bioash were identified as promising components for organo-mineral remediation systems due to their complementary fertilizing and immobilization properties. Three prospective pelletized formulations containing 10 %, 20 %, and 30 % wt. bioash were proposed for further evaluation of their remediation potential.