Lead and mercury in breast milk

Area of Science:

• Environmental Health
• Pediatric Toxicology
• Human Lactation

Background:

• Heavy metals, including mercury (Hg) and lead (Pb), pose potential neurotoxic and nephrotoxic risks, particularly to infants.
• Limited data exists on Hg and Pb levels in breast milk for the Austrian population.
• The influence of maternal lifestyle on heavy metal content in breast milk is not well-documented.

Purpose of the Study:

• To quantify mercury (Hg) and lead (Pb) levels in breast milk from healthy Austrian mothers.
• To investigate the impact of maternal lifestyle factors (residence, diet, smoking) on breast milk metal concentrations.
• To assess the potential risk to breastfed infants from current Hg and Pb exposure levels.

Main Methods:

• Collected breast milk samples (5-10 mL) from healthy mothers in urban, industrial, and rural Austrian locations (n=165).
• Administered questionnaires on maternal lifestyle factors: residence, nutrition, smoking, and dental history.
• Analyzed milk samples for Hg and Pb using atomic absorption spectrophotometry after lyophilization and wet-ashing.

Main Results:

• Low concentrations of Hg (1.59 ± 1.21 µg/L) and Pb (1.63 ± 1.66 µg/L) were detected in breast milk.
• Eight percent of samples marginally exceeded the Hg screening level; Austrian Pb levels have decreased significantly.
• Maternal residence, fish/cereal consumption, vitamin supplementation, smoking, and prematurity were associated with metal levels.

Conclusions:

• Observed Hg and Pb concentrations in Austrian breast milk do not exceed critical levels.
• Current levels of Hg and Pb in breast milk are considered safe for infants of healthy mothers.
• Theoretical risks to breastfed infants from current maternal Hg and Pb exposure can be ruled out.