Impact of biochar on the mobility of heavy metals in reclaimed sites from mining activities in the Medet mine area
Milena Harizanova
, Lyuba Nenova
, Maya Benkova
, Tsetska Simeonova
, Milchena Atsenova, Irena Atanassova
Abstract: 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.
Keywords: biochar; heavy metals; immobilization; reclaimed soils
Citation: 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
| References: (click to open/close) | Alaboudi, K. A., Ahmed, B. & Brodie, G. (2019). Effect of biochar on Pb, Cd and Cr availability and maize growth in artificial contaminated soil. Annals of Agricultural Sciences, 64(1), 95 - 102. https://doi.org/10.1016/j.aoas.2019.04.002.
Atanassova, I. D., Simeonova, Ts., Benkova, M. G., Nenova, L. G., Banov, M. & Doerr, S. H. (2020). Seasonal variation of heavy metal mobility and speciation in water repellent coal ash reclaimed Тechnosols. Journal of Environmental Protection and Ecology, 21(5), 1597 - 1609. https://doi.org/10.3390/agriculture14091631.
Atanassova, I., Benkova, M., Nenova, L., Harizanova, M., Ilinkin, V., Kirilov, I., Dimitrov, E. & Simeonova, Ts. (2023). Geogenic and pedogenic sources of metals in reclaimed technosols from the area of Asarel Medet non-ferrous smelter in bulgaria. Journal of Environmental Protection and Ecology, 24(6), 1857 - 1866. https://scibulcom.net/en/article/AQk5tvwNZBjOEN1aD7Yp.
Atanassova, I., Benkova, M., Simeonovaa, Nenova, Ts., L., Banov, M., Rousseva, S. & Doerr, S. (2019). Influence of soil water repellency on heavy metal mobility in coal ash reclaimed Technosols. Journal of Environmental Protection and Ecology, 20(4), 1667 - 1669.
Atanassova, I., Nenova, L., Simeonova, T., Benkova, M. & Ilinkin, V. (2024). Effect of biochar on heavy metal solubility and speciation in Technogenic soils around Aurubis copper smelter in Bulgaria. Biologia, 80(5), 1207 - 1220. https://doi.org/10.1007/s11756-023-01590-5 (IF 1.5)
Cui, Z., Wang, Y., Wang, N., Ma, F. & Yuan, Y. (2024). Effects of Ageing on Surface Properties of Biochar and Bioavailability of Heavy Metals in Soil. Agriculture, 14, 1631. https://doi.org/10.3390/agriculture14091631.
DECREE No 3. (2008). For Standards of Acceptable Content of Harmful Substances in the Soil. State Gazette, 71 (Bg).
Ganev, S. & Arsova, A. (1980). Methods of determining the strongly acid and the slightly acid cation exchange in soil. Soil Science and Agrochemistry, 15(3), 22 - 33 (Bg).
Gao, Y., Wu, P., Jeyakumar, P., Bolan, N., Wang, H., Gao, B., Wang, Sh. & Wang, B. (2022). Biochar as a potential strategy for remediation of contaminated mining soils: Mechanisms, applications, and future perspectives. Journal of Environmental Management, 313, 114973. https://doi.org/10.1016/j.jenvman.2022.114973.
Gustafsson, J. P., Tiberg, C., Edkymish, A. & Kleja, D. B. (2011). Modelling lead (II) sorption to ferrihydrite and soil organic matter. Environmental Chemistry, 8(5) 485 – 492. https://doi.org/10.1071/EN11025.
Ibrahim, E. A., El-Sherbini, M. A. & Selim, E. M. M. (2022). Effects of biochar on soil properties, heavy metal availability and uptake, and growth of summer squash grown in metal-contaminated soil. Scientia Horticulturae, 301, 111097. 27 July 2022. https://doi.org/10.1016/j.scienta.2022.111097.
ISO 11265:2002 - Instrumental method for routine determination of specific electrical conductivity in aqueous soil extract.
Medyńska-Juraszek, A. & Ćwieląg-Piasecka, I. (2020). Effect of Biochar Application on Heavy Metal Mobility in Soils Impacted by Copper Smelting Processes. Pol. J. Environ. Stud., 29(2), 1749 - 1757. DOI: 10.15244/pjoes/108928.
Nenova L., Zgorelec, Z., Benkova, M., Simeomova, Ts., Velichkova, N. & Atanassova, I. (2018). Solubility and availability of copper, zinc lead and iron in technosols under the effect of increasing copper levels. International Journal of Hydrology, eISSN: 2576-4454. https://medcraveonline.com/IJH/solubility-and-availability-of-copper-zinc-lead-and-iron-in-technosols-under-the-effect-of-increasing-copper-levels.html.
Nosratabad, N. A., Yan, Q., Cai, Z. & Wan, C. (2024). Exploring nanomaterial-modified biochar for environmental remediation applications. Heliyon, 10(18). https://doi.org/10.1016/j.heliyon.2024.e37123.
Perfanova, J., Atanassova, I., Harizanova, M., Nenova, L., Benkova, M., Simeonova, Ts. & Stoykova, M. (2025). Influence of biochar on the microflora in reclaimed soils in the area of the Medet mine from the Asarel-Medet metallurgical plant in Bulgaria. Bulgarian Journal of Crop Science, 62(4), https://doi.org/10.61308/CMII1237.
Stoykova, М., Aаtanassova, I., Simeonova, Ts., Benkova, M., Nenova, L., Harizanova, M. & Atsenova, M. (2024). Positive effect of biochar on heavy metal solubility and speciation in non-acidic Technosols. Sustainability, 16(16), 6891. https://doi.org/10.3390/su16166891.
van Ranst, E., Verloo, M., Demeyer, A. & Pauwels, J. M. (1999). Manual for the Soil Chemistryand Fertility Laboratory: Analytical Methods for Soils and Plants Equipment and Management of Consumables. Ghent University, Faculty of Agricultural and Applied Biological Sciences, Department of Applied Analytical and Physical Chemistry, 243. http://hdl.handle.net/1854/LU-113771.
Wraith, Jon & Or, Dani. (2001). Soil Water Characteristic Determination from Concurrent Water Content Measurements in Reference Porous Media. Soil Sci Soc. Am. J.. 65. 10.2136/sssaj2001.1659.
Zeien, H. & Bruemmer, G. W. (1989). Chemical extraction for the determination of heavy metal binding forms in soils. Mitt. Dt. Bodenkundl. Ges. 59, 505 - 510 (in German). |
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| Date published: 2026-06-25
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