International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

This study examines a combined remediation strategy that integrates humic acids derived from Ukrainian lignite with oat (Avena sativa L.) phytoremediation to restore soils contaminated with heavy metals as a result of military activities in Ukraine. Humic acids were extracted using an energy-efficient hydrocavitation method and applied to artificially contaminated peat at two dosages (1:5 and 1:10). The amendments markedly reduced the mobility and extractable concentrations of Pb, Cd, Ni, Cu, and Zn, with total decreases ranging from about 25% in the untreated control to nearly 47% under the highest humate application rate. Improved soil structure and stimulated root development contributed to enhanced plant tolerance and greater biomass production. Metal accumulation occurred predominantly in roots (68–90%), while only 10–32% was translocated into biomass, indicating effective stabilization within the soil–plant system and minimized risks for trophic transfer. These findings demonstrate that hydrocavitation-extracted lignite humates substantially reinforce phytoremediation efficiency and represent a scalable, low-cost, and environmentally sustainable solution for rehabilitating conflict-affected agricultural soils.

The present study examines the possibilities for reclamation of soils contaminated with heavy metals from the extraction of polymetallic ores with soil improvers mixture of waste – sludge from WWTP and ash from thermal power plants, through a vegetation experiment. Two herbaceous species of the genus Rumex were selected for the experiment – R. acetossela and R. patienta known for their ability to accumulate heavy metals and in particular copper. The results of the study prove the ability to use the improvers in biological reclamation of old embankments.