Bioaccumulation of potentially toxic elements in spinach grown on contaminated soils amended with organic fertilizers and their subsequent human health risk

Soil pollution with potentially toxic elements is a significant environmental problem worldwide. Such soils need reclamation, utilizing environmentally friendly and cost-effective techniques. Therefore, a study was performed with an aim to evaluate the effect of different organic amendments on bioaccumulation of potentially toxic elements in spinach grown on contaminated soils. For the experiment, soils from various mines (manganese mine (MM), chromite mine (CM), quartz mine (QM), and soap stone mine (SSM)) were amended with organic fertilizers including spent mushroom compost (SMC), vermicompost (VC), and leaf compost (LC). Spinach was grown in pots containing 5 kg growing media at 1:1:1 by weight (garden soil:mining soil:organic fertilizer). Results indicated that mining soils and organic amendments significantly affected plant growth and yield parameters and potentially toxic elements' content in spinach. Organic fertilizers amendment reduced potentially toxic elements' availability, increased spinach growth, and reduced their related health risk indices (HRI). Among organic fertilizers, VC was more effective in reducing uptake of lead (Pb), manganese (Mn), chromium (Cr), and cadmium (Cd) by 81%, 59%, 74%, and 45%, respectively; improving spinach growth and yield; and reducing HRI.