Assessment of the phytoremedical potential of Galega orientalis under the conditions of polyelemental pollution of soils with heavy metals

Abstract

Oleksiy Alieksieiev, Tkachuk Oleksandr, Oksana Vradii*, Snizhana Pankova and Artem Saliamon

The phytoremediation potential of the perennial legume crop of the Galega orientalis Lam. under conditions of polyelement contamination with heavy metals (lead, cadmium, copper and zinc) was investigated. The experiment was conducted in 2021-2025 on gray forest surface-gleyed soils at the Agronomichne research farm (Vinnytsia region, Ukraine) after carrying out an agrotechnical measure-liming. The assessment of the ecological state of the edaphotope was carried out in the 2^nd and 4^th years of the crop's vegetation using atomic absorption spectrometry, calculation of concentration coefficients (K_c) and the total soil pollution index (Z_c). It was established that long-term cultivation of Galega orientalis provides high efficiency of soil purification from copper (98.46%) and cadmium (98.33%), reducing their concentration coefficients to insignificant levels (0.04 and 0.02, respectively). The efficiency of zinc extraction was 79.63%, and lead -55.93%. In the 4^th year of vegetation, the integral index Z_c shifted into the negative zone and was -2.45 ± 0.03 (against the initial 1.52 ± 0.03), which mathematically confirms the complete detoxification of the soil profile. Analysis of plant raw materials revealed that the content of cadmium, copper and zinc in the green mass is within the safe norm. However, for lead, the maximum permissible concentration in feed was recorded to be 1.60 times higher (0.80 ± 0.01 mg/kg of absolute dry matter), which indicates the implementation of the strategy of active terrestrial phytoextraction. For practical application, a technological scheme is proposed that includes regular mowing of biomass to remove toxicants from the local circulation and its subsequent low-temperature pyrolysis or controlled combustion.