Assessment of toxic metals and trace elements in breast milk of mothers and their health risks to infants: A cross-sectional study in Ardabil, Northwest Iran

Abstract

This research aimed to assess the potential health risks for infants and measure the concentrations of heavy metal substances in the breast milk of mothers residing in Ardabil, Iran. The study was descriptive and cross-sectional in nature. Ten health centers in Ardabil City were selected for the research. The ages of participating mothers ranged from 19 to 39 years, and breast milk samples were collected from those who were 1–12 months postpartum. A 25-item questionnaire was used to evaluate the participants' exposure to heavy metals in their environment and diet. Data analysis was performed using the non-parametric Mann-Whitney U test, resulting in a p-value greater than 0.05. The average body mass index (BMI) of breastfeeding mothers was 26.26 ± 3.73. Spike recovery values ranged from 92 % to 106 %, indicating reliable performance within the ICP-MS range. The limit of detection (LOD) during routine sample analysis was 0.001 μg/L. The daily intake (DI) of lead (Pb), arsenic (As), and chromium (Cr) for infants was calculated. According to the findings, copper (Cu) had the highest average concentration in breast milk at 803.94 μg/L, while cadmium (Cd) had the lowest at 1.87 μg/L. Additionally, potassium (K) exhibited the highest average concentration at 490.49 mg/L, whereas molybdenum (Mo) had the lowest at 0.8 μg/L. The average daily intake of Pb, As, and Cr through breastfeeding was measured at 3.39, 0.799, and 3.47 μg/kg-bw/day, respectively. The results confirmed the presence of mercury (Hg), As, and Pb in every milk sample collected from lactating mothers in Ardabil, indicating potential exposure of infants to elevated levels of toxic heavy metals.