Milena Harizanova, Lyuba Nenova, Maya Benkova, Tsetska Simeonova, Milchena Atsenova and Irena Atanassova
Agricultural Academy, “N. Poushkarov” Institute of Soil Science, Agrotechnology and Plant Protection, 7 Shosse Bankya Street, 1330 Sofia, Bulgaria
Harizanova, M., Nenova, L., Benkova, M., Simeonova, Ts., Atsenova, M. & Atanassova, I. (2026). Impact of biochar on the mobility of heavy metals in reclaimed sites from mining activities in the Medet mine area. Bulg. J. Agric. Sci., 32(3), 588–600
Three reclaimed soils (~ 20 years old) formed on embankments in the Medet mine from the Assarel-Medet mining and processing complex were studied. An investigation was conducted on the influence of biochar (BC) in different doses 1%, 5%, 10% and 20% on the properties and immobilization of heavy metals in technogenic soils in a laboratory incubation experiment, for a period of six months. Mobile forms of the studied metals were determined after extraction with 0.01 M CaCl2 and 1M NH4NO3.
An increase in pH values of the studied soils was noted, both with increasing rates of biochar and over the incubation time. Biochar was successful in decreasing the mobile (0.01M CaCl2) and bioavailable (1M NH4NO3) forms of Cu, Co and Pb, however for the other studied metals, Fe, Mn and Zn there is no clear trend of the effect of biochar in decreasing their mobility and availability.
The results of this study confirm our previous findings that Cu and to some extent Pb in the soils of the area were behaving as anthropogenic pollutants, which can be immobilized by biochar, while the mobility and bioavailability of Co, Fe, Mn and Zn were less influenced by the biochar added.