Bioaccumulation of minerals and trace elements in spinach (Spinacia oleracea L.) grown under different nutrient management and their implications for human health

Nutrient management strategies significantly influence the bioaccumulation of minerals and trace elements in leafy vegetables, directly affecting crop nutritional quality and human health. This study aimed to evaluate the effects of different chemical fertilizers and organic manures on spinach ( Spinacia oleracea L.) growth, yield, mineral content, and the potential health implications of consuming these plants. A pot experiment was conducted using spinach cv. Kopi Palong in a completely randomized design with three replications. Treatments included: 100% vermicompost (VC), 100% cow dung (CD), 100% chemical fertilizers (CF), and various combinations of CF with CD or VC (75% CF + 25% CD/VC, 50% CF + 50% CD/VC, 25% CF + 75% CD/VC), plus a control. Growth parameters, mineral nutrient uptake, and trace element concentrations in edible spinach leaves were measured. Significant variations were observed in spinach growth, nutrient uptake, and trace element accumulation among the nutrient management treatments. Mixed manure and chemical fertilizer treatments produced the tallest plants with the highest dry weight and moisture content, while 100% chemical fertilizer resulted in the highest yield. Mineral uptake varied among treatments, indicating the potential to optimize nutrient profiles through specific fertilizer combinations. Trace metal accumulation followed the order Fe > Mn > Zn > Cu > Cd > Pb. The highest concentrations in fresh weight (fw) basis recorded were Fe (3.667 mg kg -1 fw in 100% VC), Mn (0.598 mg kg -1 fw in 100% CD), Zn (0.252 mg kg -1 fw in 100% CD), Cu (0.043 mg kg -1 fw in 100% VC), and Cd (0.00094 mg kg -1 fw in 50% CF + 50% VC). Pb was below detection in all treatments. Health risk assessments based on hazard indices indicated no noncancerous risk from spinach consumption. Combining organic manures with chemical fertilizers can reduce trace element contamination while enhancing spinach growth and nutrient content, offering safer and more nutritious produce for human consumption.