Assessment of Non-Carcinogenic and Carcinogenic Risks Due to Ingestion of Vegetables Grown Under Sewage Water Irrigated Soils Near a 33 Years Old Landfill Site in Kolkata, India

The present study is carried out in a major vegetable growing area of sub-urban Kolkata, India (a 33 year old dumpsite) to assess health risks due to the consumption of metal-laden vegetables. A total of 91 soil samples, 21 water samples, and 10 types of vegetables were analysed for six potentially toxic elements viz., copper (Cu), zinc (Zn), manganese (Mn), lead (Pb), cadmium (Cd) and nickel (Ni). Amounts of Cu (0.27 mgl −1 ), Mn (0.63 mgl −1 ), Pb (3.96 mgl −1 ), Cd (0.27 mgl −1 ) and Ni (0.42 mgl −1 ) in waste-water and that of Zn (326.57 mgkg −1 ), Pb (211.85 mgkg −1 ) and Cd (4.69 mgkg −1 ) in the soils of the studied area exceeded the safety limits. Type, quantity, and quality of deposited wastes and wastewater could be considered as influencing factors for varying distribution of such toxic metals in surface soils. Hierarchical cluster analyses indicated higher metal accumulation in leafy vegetables over fruit and root vegetables. Amaranthus and Sponge Gourd have been marked as the most and least contaminated vegetables, respectively in terms of collective mean hazard index (CMHI) and collective mean target cancer risk (CMTCR). Target hazard quotient (THQ) values for Pb, Cd, and cancer risk (CR) values for Pb, Cd, and Ni exceeded the safety limit of 1. Several fold higher CMHI (> 1) and CMTCR (> > 1.00E − 04) indicates severe health risks of the local population which was notably prominent in children compared to adults. The findings of the current study would serve as an effective tool for documentation of the current status and will help policymakers to take necessary measures for reducing the toxic metal pollution in the studied area.