Synergistic Interactions in Enzyme Activities During Vermiremediation of Heavy Metals (HMs) Polluted Soil: Elucidating the Impact of Eudrilus eugeniae

ABSTRACTThe vermiremediation potential of Eudrilus eugeniae was assessed in heavy metals (HMs) contaminated soil in a microcosm experiment. In detail, efficacy of E. eugeniae was investigated in terms of reduction in HMs content, enhancement in the soil enzyme activities, synergistic correlation between the HMs and enzyme activities and bioaccumulation of HMs in the earthworm’s biomass. Moreover, a seed germination assay was also conducted to assess the HMs toxicity in soil after remediation. The results showed that Eudrilus eugeniae was capable of decreasing the Cu, Zn, Mn, Cr, and Ni contents in the soil by 17.56–26.30% after 90 days of experimental trial. Introduction of E. eugeniae increased cellulase, amylase, polyphenol oxidase, peroxidase, urease, dehydrogenase, and catalase activities by 30.3–80.95% compared to controls. Earthworm addition led to a 12.98% increase in G-Mean and 2.89% increase in T-QSI values, indicating significant soil health improvement. PCA revealed the negative impact of HMs on synergistic enzyme activities during vermiremediation. HMs content in earthworm biomass increased 13-fold. Seed germination assay confirmed HMs reduction by the end of the experiment. Thus, this study demonstrated the interconnected changes in the soil enzyme activities during vermiremediation of HMs from crude oil polluted soil.KEYWORDS: Crude oilsoil enzymesabiotic stressbioaccumulationEudrilus eugeniaesoil remediation AcknowledgmentsThe authors are thankful to the Department of Botany, Gauhati University, Assam, India, for providing the basic laboratory facilities to carry out the work smoothly.Disclosure statementNo potential conflict of interest was reported by the author(s).Data availability statementThe data reported in the current study have been obtained in original upon experimentation. The datasets generated or analyzed during the current study are available from the corresponding author on reasonable request.Ethical approvalThis article does not contain any studies with human participants or animals performed by any of the authors.Author’s contributionHD provided laboratory facilities and guided GB for PhD. GB carried out the experimental works, analysis and statistical work, and wrote the M.S. under direct supervision of HD.Additional informationFundingThis research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.