Health Risk Assessment and Multivariate Statistical Analysis of Heavy Metals in Vegetables of Khyber Pakhtunkhwa Region, Pakistan

Overview

Ullah et al. (2022) measured lead (Pb), chromium (Cr), cadmium (Cd), Cu, Zn, nickel (Ni), Fe, and Mn in water, soil, and nine edible vegetable types from peri-urban D.I. Khan, Khyber Pakhtunkhwa, Pakistan. The routeable occurrence values are the edible-vegetable metal ranges for wastewater-irrigated sectors X/Y and freshwater-irrigated sector Z. Water and soil values are pathway context and should not be pooled with vegetable occurrence values.

Key numbers

Figure 2 gives the vegetable-by-sector bar plots, while the results text reports exact concentration ranges in mg kg-1. The wastewater-irrigated sectors X and Y were reported together as Pb 7-41, Cr 6-38, Cd 1.8-7.5, Cu 11.7-27, Zn 7.9-34.9, Ni 15.6-61.2, Fe 7.2-39.3, and Mn 12.4-60.4 mg kg-1. The freshwater-irrigated sector Z was reported as Pb 4.0-7.0, Cr 3-27.7, Cd 0.3-1.4, Cu 7.5-14.5, Zn 3.3-16.7, Ni 4.1-28.7, Fe 2.8-57.3, and Mn 1.6-22.2 mg kg-1.

The nine vegetable types were cauliflower, tinda, spinach, cabbage, carrot, taro/Colocasia, radish, turnip, and lettuce. The paper states that Pb, Cd, Cr, and Ni in sectors X and Y were above the WHO norm, and that in sector Z the three heavy-metal concentrations Pb, Cr, and Cd were recorded with unusually high Ni in spinach and tinda.

Table 3 reports soil-to-vegetable transfer factors. For Cd, the highest reported TFs were 3.478 in sector X Colocasia, 3.741 in sector Y turnip and Colocasia, and 9.333 in sector Z radish. For Ni, the highest reported TFs were 0.855 in sector X lettuce, 0.949 in sector Y lettuce, and 12.766 in sector Z spinach.

Tables 4-6 report EDIM and HRI values for adults and children. The wastewater-sector tables report high adult HRI values for Cd: sector X Colocasia 1.72E+02, carrot 1.43E+02, cabbage 1.31E+02, and lettuce 1.31E+02; sector Y Colocasia 1.73E+02, turnip 1.73E+02, carrot 1.54E+02, and lettuce 1.38E+02. In freshwater sector Z, adult HRI values in Table 6 were all below 1, including Cd 7.33E-01 in Colocasia, 6.81E-01 in cabbage and radish, 6.28E-01 in spinach, cauliflower, and lettuce, 5.76E-01 in carrot, 4.71E-01 in tinda, and 3.14E-01 in turnip.

Methods (brief)

The study sampled three sectors around D.I. Khan between October 2019 and April 2020. Sectors X and Y had a long history of mixed city-runoff and textile-industry wastewater irrigation, while sector Z used underground freshwater. The edible portions of vegetables were washed, acidified with 0.1 M HCl for 30 min, rinsed with distilled water, oven-dried for 24 h at 60 °C, powdered, digested with HNO3, H2SO4, and HClO4, and analyzed by atomic absorption spectrophotometry. The authors report repeated analysis against NIST plant standard reference material with results within +/- 1% of certified values.

Implications

This source supports wastewater-irrigated vegetable occurrence context for leafy vegetables, spinach, root/tuber vegetables, and non-root vegetables in Pakistan. It should be routed as local peri-urban agricultural evidence, not as a national Pakistan vegetable baseline. The product values should remain separated from the water and soil tables because the latter are exposure-pathway context rather than edible-product concentrations.

Related evidence

• Spinach
• Cabbage
• Cauliflower
• Carrot
• Lettuce
• Root vegetables
• Non-root vegetables
• Leafy Vegetables
• Spinach
• Leafy / Green Vegetables, Other
• Root and Tuber Vegetables
• Non-Root Vegetables
• Lead
• Chromium
• Cadmium
• Copper
• Zinc
• Nickel
• Iron
• Manganese

Update history

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