Evaluating Municipal Solid Waste-Derived Vermicompost for Soil Improvement, Plant Performance, and Associated Health Risk in Spinach.

Abstract

The management of municipal solid waste (MSW) is a global challenge, and composting provides a sustainable solution for converting organic fractions into compost. This study investigated the effects of municipal solid waste vermicompost (MSWVC) on soil properties, morphological, biochemical and HM accumulation in spinach, along with associated human health risks. Pot experiments were conducted with six treatments: 20% (T1), 40% (T2), 60% (T3), 80% (T4) MSWVC doses, inorganic fertilizer (IF), and control (T0). Soil analyses revealed significant (p < 0.05) improvements in soil pH, TOC, TKN, and available phosphorus under MSWVC amendments. Biochemical parameters, including chlorophyll, carotenoids, protein, ascorbic, phenolics, and proline, were enhanced at moderate doses (20-40%) (p < 0.05) at 45 days after sowing (DAS). However, higher doses (> 60%) elevated lipid peroxidation and stress responses to HM. BCF indicated that Pb and Cu accumulation decreased with increasing MSWVC (p > 0.05), whereas Zn and Ni exhibited higher root and shoot uptake (p < 0.05). The TF showed a declining trend for Pb and Cr, whereas Ni and Zn increased at higher doses. The human health risk assessment revealed non-carcinogenic risks within safe limits (THQ < 1). However, the additive impact of HM (HI) suggested a potential risk at higher doses of MSWVC T4 (HI= 0.99 and HI= 1.38) in both children and adults. Overall, while MSWVC enhances soil properties, application must be carefully controlled to balance agricultural benefits against toxicity and food safety risks.