Heavy Metal Contamination, Consumption and Toxicity Assessment in Vegetables in Delhi NCR

The present study was carried out to analyse the vegetables consumption patterns (potato, carrot, tomato, spinach, mustard, and okra), contamination levels, and toxicity assessment due to intake of heavy metals (As, Cd, Cr, Hg and Pb) contaminated vegetables at five selected sites (Alipur, Shahdara, Kanjhawala, Mehrauli, and Najafgarh) in Delhi NCR. According to the findings, the highest gross per capita per day vegetable consumption was found in Shahdara (0.314 kg), followed by Najafgarh (0.307 kg). It was also found that potatoes had the highest per capita daily consumption of vegetables, followed by tomatoes. It was also observed that, in selected vegetables, the consumption of root vegetables was higher than that of other vegetables. In soil samples, heavy metals (As-0.186-0.474, Cd-0.150-0.699, Cr-0.128-0.715, Pb-3.256-4.971, and Hg-0.206-0.773 μg g⁻¹) were observed below the permissible level of FAO/WHO standards. In irrigation water samples, Cd (0.001-0.013 μg g⁻¹) was noted to be higher than the FAO permissible limit (0.01 μg g⁻¹) at all the sites. In most of the cultivated areas in vegetable samples, Hg content was observed below the detection limit except in potato (0.096 μg g⁻¹), tomato (0.075 μg g⁻¹), carrot (0.109 μg g⁻¹) and okra (0.012-0.016 μg g⁻¹) at Najafgarh and okra (0.195-0.265 μg g⁻¹) at Mehrauli. In most of the vegetables, Cd content (>0.20 μg g⁻¹) was detected at levels higher than permissible limits (0.20 μg g⁻¹) except for tomato (0.009-0.195 μg g⁻¹). The higher values of TF were observed at Mehrauli and Kanjhawala in spinach (0.99) and okra (0.99) for Cd and As, respectively. The maximum average values of MPI were found in spinach (0.33 μg g⁻¹), followed by okra (0.0.25 μg g⁻¹). This study concludes that irrigation with contaminated wastewater over time is a major cause of the buildup of toxic heavy metals in soil and vegetables, as well as the overall load of metal pollution in vegetables, which may threaten the quality of vegetables and the health of consumers.