Survey of lead, cadmium and fluoride in human milk and correlation of levels with environmental and food factors.

Lead, cadmium and fluoride were determined in 210 samples of human milk and the mean and median levels and ranges found were 1.04 and 0.55 ng/g (range less than 0.05-15.8 ng/g) for lead, 0.08 and 0.06 ng/g (range less than 0.002-4.05 ng/g) for cadmium, and 7.08 and less than 4 ng/g (range less than 2-97 ng/g) for fluoride. For mothers taking no fluoride supplements and living in communities with fluoride (1 microgram/g) in the drinking-water, the mean fluoride level was 9.8 ng/g. Where no fluoride was present in the drinking-water, the mean level was 4.4 ng/g. Geometric means for all non-zero lead, cadmium and fluoride concentrations were 0.566, 0.063 and 12 ng/g, respectively. Statistical correlation of levels with some dietary and environmental factors showed that lead levels were most strongly correlated with the age of the house (P less than 0.001), with maternal exposure to heavy traffic for more than 5 yr (P = 0.011), and with coffee consumption (P = 0.034). Fluoride levels correlated strongly (P = 0.007) with the presence of fluoride in the drinking-water. Cadmium levels correlated strongly with exposure to cigarette smoke (P = 0.005 if the mother smoked and P = 0.003 if the father smoked and the mother did not smoke).