Toxicological implications and human health risk assessment of heavy metal contaminated green leafy vegetables and their cultivated soil

In the present study, fourteen green leafy vegetables, including spinach, coriander, spring onion, curry, dill, fenugreek, green amaranth, and red amaranth, along with their rhizospheric soils from Chitradurga, Davangere, Tumkur, and Haveri districts of central Karnataka, India, were examined to regulate heavy metal concentrations by ICP–MS. Human health risk assessment was performed by calculating the estimated daily intake (EDI), hazard quotient (HQ), hazard index (HI), and target cancer risk (TCR) to evaluate potential non-carcinogenic and carcinogenic risks associated with vegetable consumption, while transfer factor (TF) analysis assessed soil-to-plant metal translocation into the food chain. Further, cytotoxic effects were evaluated using the MTT assay using HDF cells. Results showed that among the analyzed metals, iron (Fe) and manganese (Mn) were detected at the highest concentrations in green leafy vegetables, whereas cadmium (Cd) and arsenic (As) occurred at comparatively lower levels. Health risk assessment revealed elevated HQ/HI values. SHM3, SHM6, SHM12, and SHM14 exhibited below 1, indicating potential non-carcinogenic health concerns, while SHM2 and SHM12 exhibited comparatively higher values, indicating possible long-term carcinogenic risk associated with chronic exposure to heavy metals. TF analysis demonstrated variable soil-to-plant metal translocation, with cadmium showing the highest transfer efficiency. Furthermore, manganese chloride exposure reduced HDF cell viability to 49.36% after 72 h, with an IC 50 value of 487.00 μg/mL. The findings of the current study suggested that most green leafy vegetables from the central Karnataka region remained within acceptable safety limits. However, certain samples indicated potential toxicological risks, therefore requiring regular monitoring to protect public health.