Can heavy metals and PFAS pass from a mother's blood into breast milk during nursing?

What's actually in it

A nursing mother's breast milk reflects what's in her blood. Arsenic from rice and water, cadmium from vegetables and grains, lead from old paint dust, mercury from fish, and PFAS from nonstick cookware and food packaging can all make it into breast milk. The amounts depend on how much the mother was exposed to before and during pregnancy.

Breast milk remains the best food for babies. But understanding what else it may carry helps parents make informed choices.

What the research says

A 2026 review in Environ Int compiled data on how arsenic, cadmium, lead, mercury, and PFAS transfer from maternal blood into breast milk. The review confirmed that all five pollutant groups pass into breast milk, though at different rates.

PFAS transferred most efficiently. Breast milk PFAS levels closely tracked maternal blood levels, and breastfeeding actually lowered the mother's PFAS burden while increasing the infant's. Mercury from fish consumption also transferred readily, with higher levels in mothers who ate more seafood.

Lead transfer was moderate and depended heavily on the mother's lifetime bone stores, since lead is stored in bones and released during breastfeeding. Cadmium and arsenic transferred at lower rates but were still detectable.

The review emphasized that breastfeeding benefits still outweigh the risks for most mothers. But reducing exposure before and during pregnancy matters. Filter your water, vary your diet, avoid nonstick cookware, and limit high-mercury fish like tuna and swordfish during nursing.