Twenty-nine samples of human milk were analyzed for lead content. The mean lead concentration was 0.026μg/ml, with a range from 0.006μg/ml to 0.058μg/ml. Lead concentrations in human milk do not appear to constitute a health hazard to infants.
Dillon HK, Wilson DJ, Schaffner W. Lead Concentrations in Human Milk. Am J Dis Child. 1974;128(4):491-492. doi:10.1001/archpedi.1974.02110290061010