Assessment of health risks from heavy metal contamination in breast milk of urban mothers in Malaysia

Breast milk is the essential source of nutrition for infants, yet global studies have increasingly identified the presence of heavy metals in breast milk. This study aims to quantify the levels of heavy metals in breast milk and assess the associated health risk to infants in Malaysia. This cross-sectional study included 106 healthy breastfeeding mothers who completed a questionnaire on maternal exposures, infant risk factors, and socio-demographic data. Breast milk samples (collected 1–3 months postpartum) were analyzed for concentrations of lead (Pb), cadmium (Cd), chromium (Cr), and arsenic (As) levels. Our findings revealed that 63.2% (n = 67) of the breastmilk samples exceeded WHO’s recommended levels of As; 28.3% (n = 30) exceeded the acceptable limit for Cd; 97.2% (n = 103) exceeded recommended range of Cr; and 40.6% (n = 43) exceeded the recommended range of Pb. Notably, dental amalgam fillings were identified as a potential source of exposure, showing a moderately strong correlation with Cd (r = 0.369, p < 0.01) and Pb (r = 0.439, p < 0.01) levels. Furthermore, caesarean section deliveries were moderately correlated with increased Cd levels in breast milk (r = 0.326, p < 0.05). Approximately 93.4% (n = 99) of the infants had a Hazard Index (HI) above 1, indicating potential non-carcinogenic health risks, with the maximum HI reaching 17.368. These findings underscore the critical need for further research and intervention strategies to mitigate the risk of heavy metal exposure in infants via breast milk.