Risk Assessment of Heavy Metal Contamination in Soil for Sustainable Environmental Management in Urban and Rural Areas of Gujrat District, Pakistan

This study was conducted to assess the risk of heavy metal contamination in soils from the selected sampling areas. The study aimed to determine whether soil properties, including electrical conductivity (EC), pH, and organic matter (OM), affect heavy metal concentrations in soil. Composite soil samples were collected and analyzed using Atomic Absorption Spectroscopy (AAS) for heavy metal concentrations at a depth of 0–15 cm, following the order of Zn > Pb > Cd > Cu. In addition, human health risk assessments using Average Daily Dose (ADD), Hazard Index (HI), Total Hazard Quotient (THQ), and Carcinogenic Risk Assessment (CRA) were conducted for adults and children via dermal contact, ingestion and inhalation. The results showed no significant correlation between heavy metal concentrations and soil physicochemical properties. Although Zn and Cu (r = 0.62, p < 0.01) and Cu and Pb (r = 0.57, p < 0.01) showed a moderately positive relationship, representing common, familiar contamination sources probably from industrial activities and vehicular emissions. In addition, Zinc showed a weak negative correlation with pH (r = −0.28, p < 0.01), indicating reduced metal availability in alkaline soils. However, the health risk assessment revealed that children in urban areas face higher contamination risks, with a Hazard Index (HI) of 0.06, compared to 0.01 in rural children. Carcinogenic risk assessment revealed that lead (Pb) and Cadmium (Cd) pose the highest risks, with cumulative risk for urban children (CR = 1.99 × 10−4) reaching the upper threshold of the acceptable range. These results emphasize the urgent need for pollution control measures in urban environments. Future studies could explore specific contamination pathways and remediation strategies to minimize human health risks. This study contributes to sustainability by identifying soil contamination risks and providing baseline data to inform safer land use planning. The findings support sustainable agricultural practices and evidence-based policy decisions aimed at protecting ecosystems and human health.