WHO collaborative breast feeding study. II. Levels of lead and cadmium in Swedish human milk, 1978-1979.

Individual samples of human milk collected in Uppsala at 3 months post partum (18 samples) and 6 months post partum (23 samples) from 21-35-year-old healthy mothers were analysed for lead and cadmium by flameless atomic absorption spectrometry. The median lead content in the 41 samples was 2 microgram/kg fresh weight (range 0.5-9.0 microgram/kg), and the median cadmium level was 0.1 microgram/kg. There were no appreciable differences between the 3-month and 6-month samples as regards lead or cadmium levels. The calculated median weekly intakes of lead and cadmium by the 3-month-old infants (who received nothing else except breast milk) were approx. 2 microgram and 0.1 microgram/kg body-weight, respectively. There is no reason to believe that these low intakes of lead and cadmium constitute any risk to the health of the child. The intake of these metals by the breast-fed infant is likely to be the same as or somewhat lower than that of infants fed human milk substitutes and certainly less than that of children fed cereal-based infant foods.