This scoping review examined the persistent presence of POPs (PCBs, PFAs, pesticides, flame retardants) and heavy metals (primarily Pb and Cd) in breast milk, searching MEDLINE and Google Scholar for articles published 1995–2023. Of 341 primary studies identified, 54 were selected for synthesis. The review is primarily focused on organic pollutants, with heavy metals as a secondary concern. Key metal findings: EU regulatory limits for Pb in breast milk are 0.015 mg/L (15 µg/L) and for Cd are 0.005 mg/L (5 µg/L). The review notes that heavy metal exposure occurs via the diet (over 90% for Cd in non-smokers, 100% for MeHg), that place of residence (urban vs. rural) correlates with heavy metal exposure, and that smoking increases Pb in breast milk. The review situates breast milk contamination within the ‘One Health’ concept, noting that breast milk quality serves as an indicator of overall environmental health.
Key numbers
Specific heavy metal concentration data from the 54 included articles are not fully quantified in the extracted body text (the review is primarily descriptive/qualitative for metals). Reference values cited:
Regulatory/reference limits cited in review:
- Pb in breast milk: EU reference = 0.015 mg/L (15 µg/L)
- Cd in breast milk: EU reference = 0.005 mg/L (5 µg/L)
Exposure determinants identified:
- Pb: positive association with urban residence (p < 0.05), smoking (p = 0.024), and well water consumption (p = 0.046)
- As: positive association with urban residence (p = 0.013)
- Cd: non-smokers: >90% of exposure from diet; no specific association with residence cited
POPs context (not metals): PCBs 0.123 µg/g lipid weight; PFOA 0.022 µg/L; PFOS 0.021 µg/L — these are the primary quantitative focus of the review.
The heavy metals section of this review is limited in quantitative scope. The Katrynska et al. (2026) review katrynska2026-human-milk-biomonitor-toxic-metals-review provides more comprehensive metal-specific data.
Methods (brief)
Scoping review per PRISMA checklist. Databases: MEDLINE, Google Scholar. Date range: 1995–2023. Three reviewers for title/abstract and full-text screening. Inclusion: English-language peer-reviewed studies on POPs and heavy metals in breast milk with methodology reported; includes infant formula vs. breast milk comparisons. Not a systematic review; no formal risk-of-bias assessment or meta-analysis. 341 studies identified; 54 selected.
Implications
Certification: The EU reference limits cited (Pb 15 µg/L, Cd 5 µg/L) in breast milk are useful regulatory anchors for the biomonitoring literature. The review confirms that breastfeeding remains WHO-recommended even with pollutant presence, but that reducing maternal environmental exposure is a public health priority.
Courses: The ‘One Health’ framing — breast milk contamination as indicator of environmental health — is a useful teaching concept. The smoking-Pb correlation and diet-Cd correlation are practical dietary guidance entry points.
App: Breast milk is not in the app’s ingredient-list model. This review primarily supports the health sections.
Microbiome: Heavy metal exposure to infants via breast milk affects gut microbiome colonization; cross-link when relevant microbiome pages are created.