Recycling Stone Mine Tailings Through Vermicomposting for Sustainable Tomato Cultivation: An Integrated Appraisal of Agronomic Performance, Biochemical Attributes and Dietary Health Risk Assessment

The disposal of stone mine tailings (SMTs) near agricultural lands has become a major environmental concern because of their elevated concentrations of environmentally hazardous metals (EHMs). The minimization of the potential detrimental effects of soil pollution on crop cultivation and food safety are the major concerns in modern agricultural practice. Vermitechnology has emerged as a sustainable bioconversion approach for biotically stabilizing mine tailings into a nature-friendly organic amendment. However, the agronomic potential and environmental safety of vermiprocessed stone mine tailings remain poorly understood. To fill this research gap, this study assessed the effectiveness of mine-tailing-derived vermicompost as an organic amendment for Solanum lycopersicum L. (tomato) cultivation. Vermicompost was prepared from both inorganic mine tailings and organic cow dung (1:1 and 2:1 ratios, w/w) together using earthworm Eisenia fetida species. The results demonstrated that the treatment amended with 1:1 vermicomposted tailings supplemented with the recommended dose of chemical fertilizer (T3) outperformed all other treatments by enhancing soil microbial activity, the concentration of bioavailable NPK, improved fruit yield, different biochemical parameters, and reduced post-harvest bioavailable Cr, Ni, Cu, Pb, and Cd concentration. Severity Adjustment Margin of Exposure (SAMOE) analysis indicated estimated dietary risk (Class 5) for Cr (VI) and Cd in tomatoes grown on untreated mine tailings, whereas vermicompost-amended treatments reduced the risk to low or negligible levels. Overall, the findings suggest that vermicomposted stone mine tailings emerged as a potential complementary soil amendment and an eco-friendly strategy which improve crop growth while reducing metal availability and its associated health risks.