Breast milk contamination by toxic metals in active and passive smokers: A hidden threat to infant health.

The presence of environmental contaminants in breast milk has become a major public health issue. Smoking has been recognized as a risk factor that can raise the concentration of pollutants in breast milk. This study was aimed at comparing the metal(oid)s levels in breast milk from active and passive smoker women, and assessing the associated health risks for infants consuming their milk. Milk samples were obtained one day after delivery. Inductively coupled plasma mass spectrometry (ICP-MS) technique was used to determine the metal(oid)s concentrations in samples. The mean ± SD concentration of Cd, Pb, Co, As, Cr and Mn in the active smoker were 1.92 ± 2.17, 17.5 ± 11.26, 0.64 ± 0.51, 3.48 ± 2.7, 1.31 ± 1.65 and 18.01 ± 8.3 μg/L, respectively and were significantly higher than passive smoker and control groups. The concentration of all metal(loid)s (except Cu and Zn) were significantly different between three groups (p-value˂0.001). The total cancer risk (TCR) in all groups was more than 1 × 10-4, which indicates a significant risk of cancer development. The findings regarding the impact of smoking and environmental tobacco smoke (ETS) exposure on lactating women and their infants underscore the urgent need for increased awareness and preventive measures.