**Background:** Food contamination by heavy metals from wastewater irrigation is a major public health concern, particularly in low- and middle-income countries where untreated wastewater is routinely used for agriculture. In Pakistan, approximately 25.61% of the population has access to clean drinking water, and untreated industrial and municipal wastewater is commonly used for crop irrigation. This study was conducted in the Bhakkar District of Punjab, Pakistan, to evaluate heavy metal concentrations in wastewater, soil, and vegetables, and to assess the potential health risks to local consumers.
**Methods:** The study area comprised three sampling zones: Darya Khan (DK), Bhakkar (BK), and Sarai Mahajir (SM), located approximately 10 km apart. A total of 72 wastewater samples (24 per zone), soil samples collected at 30–35 cm depth, and 108 vegetable samples from nine species (including Spinacia oleracea, Brassica oleracea var. capitata, Brassica oleracea var. botrytis, Brassica rapa subsp. rapa, Raphanus sativus, Colocasia esculenta, Benincasa fistulosa, Daucus carota subsp. sativus, and Lactuca sativa) were collected. Heavy metals (Cd, Co, Fe, Mn, Ni, Pb) were analyzed using atomic absorption spectrophotometry. Physicochemical parameters (pH, EC, TDS) were measured. Health risk assessment was performed using the Daily Intake of Metals (DIM) and Health Risk Index (HRI), calculated from metal concentrations, vegetable consumption data (collected via questionnaire from 150 healthy individuals), and reference oral doses. The heavy metal transfer factor (HMTF) from soil to vegetables was also calculated.
**Key Results:** Wastewater pH ranged from 3.00 to 5.09 across zones, below the WHO acceptable limit of 6.5–8.5. EC (65–97 µS/cm) and TDS (25.3–97.0 mg/L) were below WHO limits. All heavy metals in wastewater except Co exceeded WHO permissible levels. In soil, heavy metal concentrations were within WHO limits, but ANOVA showed Ni and Mn were significantly different at p ≤ 0.001 levels. In vegetables, Pb, Cd, and Ni concentrations exceeded WHO permissible limits across all three zones. The HMTF was highest for Cd, Co, Ni, and Zn. The DIM for Pb, Cd, and Ni in wastewater-irrigated vegetables exceeded tolerable daily intake rates for both adults and children. The HRI for Pb ranged from 0.902 to 4.19 for adults and 1.04 to 4.82 for children across zones; for Cd, HRI ranged from 0.351 to 3.67 for adults and 0.404 to 4.22 for children. Ni HRI exceeded 1 in Spinacia oleracea, Benincasa fistulosa, and Lactuca sativa. All HRI values for fresh-water-irrigated vegetables were below 1.
**Clinical Implications:** The study demonstrates that consumption of vegetables irrigated with untreated wastewater in Bhakkar, Pakistan, poses significant non-carcinogenic health risks, particularly from Pb and Cd exposure, which had HRI values >1 across all vegetables studied. Children are at higher risk due to lower body weight and higher relative intake. Chronic exposure to these metals may lead to renal failure, neurological impairment (including IQ reduction in children), skeletal damage, and cancer. The findings highlight the urgent need for regulatory intervention, including treatment of wastewater before agricultural use, regular monitoring of heavy metals in soil and crops, and public health advisories for communities relying on wastewater-irrigated produce.