A scoping review of uranium and other radioactive heavy metals in breast milk and their impact on early life health.

BACKGROUND

Radioactive heavy metals, including uranium, strontium-90, caesium-137, radium, thorium, and plutonium, pose potential health risks to nursing infants through breast milk transfer. Understanding the extent of contamination, transfer mechanisms, and health implications is critical for public health policy.

OBJECTIVE

This scoping review synthesises evidence on radioactive heavy metal contamination in breast milk, maternal-infant transfer mechanisms, and associated health impacts on early life development.

METHODS

A comprehensive scoping literature search was conducted in December 2024 across multiple electronic databases. After deduplication, 161 unique papers remained. An AI-assisted relevance scoring approach (SciSpace biomedical agent) was used to prioritize screening; final eligibility decisions and data extraction were performed by the authors. Thirty studies were included for synthesis.

RESULTS

Evidence demonstrates measurable concentrations of strontium-90, caesium-137, uranium, and radium in breast milk following environmental contamination events (Chernobyl, Techa River, nuclear weapons testing) and in regions with naturally elevated radioactivity. Transfer rates vary by radionuclide, with strontium-90 showing significant maternal-infant transfer. Biokinetic models indicate dose-dependent accumulation in infant tissues. Limited direct evidence exists for specific health outcomes, though theoretical risk assessments suggest potential impacts on hematopoietic development, bone metabolism, and long-term cancer risk.

CONCLUSIONS

While breast milk contamination with radioactive heavy metals is documented in specific contexts, the health benefits of breastfeeding generally outweigh risks except in acute high-exposure scenarios. Gaps remain in understanding long-term neurodevelopmental and growth impacts. Enhanced biomonitoring and longitudinal studies are needed to inform evidence-based public health guidance.