Heavy metal concentrations in composite breast milk and health risk assessment for breastfed infants in Ho, Ghana

Background Breast milk is the optimal source of infant nutrition but may serve as a pathway for exposure to environmental contaminants. Objectives To quantify aluminum (Al), arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) in composite breast milk and assess non-carcinogenic and carcinogenic risks to exclusively breastfed infants in Ho, Ghana. Methods A cross-sectional study of 47 lactating mothers was conducted. Composite samples (colostrum, transitional, mature milk) were pooled per participant. Samples were digested with nitric acid and hydrogen peroxide and analyzed using ICP-OES with reference to EPA Method 200.7. Estimated daily intake (ADI), hazard quotient (HQ), and carcinogenic risk (CR) were calculated. Results Mean concentrations (μg/L) were: Al 0.108, As 0.037, Hg 0.018, Pb 0.006, Cd 0.003. All HQs were <1, indicating low potential for non-carcinogenic effects under the exposure assumptions applied. Arsenic produced the highest lifetime carcinogenic-risk estimate, ranging from 9.25 × 10 −7 under typical intake to 1.72 × 10 −6 under upper intake; these estimates are conservative because total rather than inorganic arsenic was measured. A significant association was observed between Cd levels and parity (p = 0.037). Conclusion Heavy metal concentrations in composite breast milk were generally low, and estimated non-carcinogenic hazard quotients were below 1 under both typical and upper milk-intake scenarios. The findings support continued breastfeeding while highlighting the importance of environmental monitoring and more refined contaminant assessment.