Orenburg, Russian Federation
Orenburg, Russian Federation
Orenburg, Russian Federation
The aim of this study was to evaluate the effect of a bacterial preparation based on Bacillus sp. and lead, both separately and in combination, on the physiological state of Eisenia fetida earthworms under controlled laboratory conditions, for a preliminary assessment of the potential risks and benefits of using this bacterial strain in the bioremediation of lead-contaminated soils. Soil isolates of Bacillus spp. were isolated from samples from the territory of PJSC Gai Mining and Processing Plant. Four experimental groups were tested for the experiment: control (distilled water), Bac+H₂O, Pb+H₂O, Pb+Bac. A decrease in the relative weight of earthworms to 68.8%, relative to the control, by day 14 was recorded in the variant with lead without bacteria (Pb + H2O). In the combined group (Pb + Bac), a consistently higher value was recorded throughout the observation period: on day 3, worm weight exceeded the control by 11.7%, on day 14 by 15.6%, and by day 21 by 19.3%. Thus, the presence of Bacillus licheniformis-resistantPb bacteria neutralizes the toxic effect of lead and promotes worm growth. The study confirms the feasibility of using biological test systems, in particular Eisenia fetida, for an objective assessment of the effectiveness and safety of bioremediation technologies. The obtained data highlight the potential of using Bacillus bacteria to reduce the phytotoxicity of heavy metals and restore soil ecosystems.
bioremediation, lead (Pb), Bacillus, Eisenia fetida, soil toxicity, bioavailability
1. Barancevich, E.P. (2014). Primenenie MALDI–TOF mass–spektrometrii v klinicheskoj mikrobiologii. Translyacionnaya medicina, 6, 23-28. (in Russ.).
2. Ahemad, M., & Kibret, M. (2014). Mechanisms and applications of plant growth promoting rhizobacteria: current perspective. Journal of King Saud University – Science, 26(1), 1-20. https://doi.org/10.1016/j.jksus.2013.05.001
3. Asif, L., Tehami, S., Qadeer, Y.K., Virani, S.S., Lavie, C.J., & Krittanawong, C. (2025). Toxic grounds: A narrative review of the role of heavy metal soil and water contamination in cardiovascular disease development. Heart and Mind, 9(6), 527-537. https://doi.org/10.4103/hm.HM-D-24-00108
4. Alotaibi, B.S., Khan, M., & Shamim, S. (2021). Unraveling the underlying heavy metal detoxification mechanisms of Bacillus species. Microorganisms, 9(8), 1628. https://doi.org/10.3390/microorganisms9081628
5. Calabrese, E.J., & Baldwin, L.A. (2003). Hormesis: the dose-response revolution. Annual Review of Pharmacology and Toxicology, 43(1), 175-197. https://doi.org/10.1146/annurev.pharmtox.43.100901.140223
6. Christopher, J.M., Sridharan, R., Somasundaram, S., et al. (2021). Bioremediation of aromatic hydrocarbons contaminated soil from industrial site using surface modified amino acid enhanced biosurfactant. Environmental Pollution, 289, 117917. https://doi.org/10.1016/j.envpol.2021.117917
7. Dixit, R., Malaviya, D., Pandiyan, K., Singh, U.B., Sahu, A., Shukla, R., Singh, B.P., Rai, J.P., Sharma, P., Lade, H., & Paul, D. (2015). Bioremediation of heavy metals from soil and aquatic environment: an overview of principles and criteria of fundamental processes. Sustainability, 7(2), 2189-2212. https://doi.org/10.3390/su7022189
8. Gadd, G.M. (2010). Metals, minerals and microbes: geomicrobiology and bioremediation. Microbiology, 156(3), 609-643. https://doi.org/10.1099/mic.0.037143-0
9. ISO. (1993). ISO 11268-1:1993 Soil quality – Effects of pollutants on earthworms – Part 1: Determination of acute toxicity to Eisenia fetida/Eisenia andrei. International Organization for Standardization.
10. Kabata-Pendias, A. (2010). Trace elements in soils and plants (4th ed.). CRC Press. https://doi.org/10.1201/b10158
11. Ma, Y., Oliveira, R.S., Freitas, H., & Zhang, C. (2016). Biochemical and molecular mechanisms of plant-microbe-metal interactions: relevance for phytoremediation. Frontiers in Plant Science, 7, 918. https://doi.org/10.3389/fpls.2016.00918
12. Mulligan, C.N., Yong, R.N., & Gibbs, B.F. (2001). Remediation technologies for metal-contaminated soils and groundwater: an evaluation. Engineering Geology, 60(1-4), 193-207. https://doi.org/10.1016/S0013-7952(00)00101-0
13. Nagajyoti, P.C., Lee, K.D., & Sreekanth, T.V.M. (2010). Heavy metals, occurrence and toxicity for plants: a review. Environmental Chemistry Letters, 8(3), 199-216. https://doi.org/10.1007/s10311-010-0297-8
14. OECD. (2004). Test No. 222: Earthworm reproduction test (Eisenia fetida/Eisenia andrei). OECD Guidelines for the Testing of Chemicals, Section 2. OECD Publishing. https://doi.org/10.1787/9789264070325-en
15. Sahoo, S., & Goli, D. (2020). Bioremediation of lead by a halophilic bacteria Bacillus pumilus isolated from the mangrove regions of Karnataka. International Journal of Scientific Research, 9(7), 1337-1343.
16. Van Gestel, C.A. (2012). Soil ecotoxicology: state of the art and future directions. ZooKeys, (176), 275-296. https://doi.org/10.3897/zookeys.176.2275
