Heavy metals contamination in water, soil, and potatoes in Sargodha and Sillanwali, Pakistan, with human health implications

The assessment of contamination level is significant in environmental pollution, as it is largely attributed to anthropogenic activities. Concerning this aim, the present survey study was conducted to determine concentrations of the selected heavy metals: cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), lead (Pb), nickel (Ni), and zinc (Zn), and, in water, soil, potato tissues, human blood serum across tubewell (TW), canal water (CW), and sewage water (SW) irrigated sites in Sargodha and Sillanwali during 2023–2024. The targeted heavy metals were analyzed following standard procedures using an atomic absorption spectrophotometer. The results showed that the concentration of tested heavy metals, such as Pb, Fe, Cr, Zn, and Ni, in water samples was found below the permissible limits by the World Health Organization (WHO). Whereas Cd (0.15–0.48 mg L⁻¹), Cu (0.33–1.22 mg L⁻¹), and Mn (0.04–0.35 mg L⁻¹) were above the permissible limits of WHO. In case of soil samples, all the tested heavy metals were found below the permissible limits except Fe (10.4–17.8 mg kg⁻¹). In case of potato tissue samples, Pb (0.13–0.95 mg kg⁻¹), Mn (1.22–3.45 mg kg⁻¹), and Ni (0.14–0.47 mg kg⁻¹) were above the permissible limits of WHO. The pollution indices, including contamination factor (CF = 0.0040–0.37), enrichment factor (EF = 0.0081–0.91), estimated daily intake (EDI = 0.0009–0.28), hazard quotient (HQ = 0.0014–0.94), and bioconcentration factor (BCF = 0.04–0.47), were determined. The concentration of metals was found to be high at site SW₁ (sewage water site-1) and less at site TW₂ (tubewell water site-2); however, the values of all indices were still found to be below 1, indicating that levels of metals at all sites were found within safe permissible limits. Metal accumulation in the edible parts of food crops due to the use of untreated wastewater can lead to toxicity in humans. Although treating wastewater for irrigation purposes is crucial, it is more vital to treat it for human health protection before its use.