Assessment of Heavy Metal Contamination in Soils Near Municipal Waste Dumps: A Case Study in Babylon Governorate, Iraq

The study evaluated heavy metal contamination and associated health risks in surface soils collected from a municipal waste dumpsite in Babylon Governorate, central Iraq. Fourteen soil samples (0–25 cm depth) were analyzed for Zn, Cd, Ni, Cr, Cu, and Pb using ICP-MS after HNO3 digestion. Pollution indices, including contamination factor, pollution load index, and geo-accumulation index, were calculated against upper continental crust background values. Non-carcinogenic (Hazard Quotient; Hazard Index) and carcinogenic risks (Excess Lifetime Cancer Risk) were assessed via ingestion, inhalation, and dermal exposure pathways following USEPA guidelines. Results revealed mean concentrations (mg/kg) of Zn = 117.2, Cd = 2.32, Ni = 70.4, Cr = 65.8, Cu = 79.6, and Pb = 44.2, all exceeding global soil averages and, for Cd and Cu, surpassing upper continental crust values. PLI values classified samples H2, H4–H7, and H10 as highly polluted (PLI > 2), driven primarily by Cd, Cu, and Pb, while H1, H3, H8–H9, H11–H12, and H14 showed moderate pollution (1 ≤ PLI < 2). I₉ₑₒ scores indicated heavy to extreme contamination (I₉ₑₒ ≥ 3) in H2 and H10, and moderate to high pollution (2 ≤ Igeo < 3) in several others. Cf values highlighted Cd as the most problematic metal (Cf up to 7.94). Health risk assessment showed that six highly polluted samples (H2, H5, H10) had HI > 1, indicating potential non-carcinogenic effects, and ELCR values (up to ~1.5 × 10⁻³) approaching or exceeding acceptable cancer risk thresholds. Low-pollution samples (H0, H13, H14) remained within safe limits for both HI and ELCR.