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Concentration of mercury, cadmium, and lead in breast milk from Norwegian mothers: Association with dietary habits, amalgam and other factors

Vollset, Marie, Iszatt, Nina, Enger, Øyvind, Gjengedal, Elin Lovise Folven, Eggesbø, Merete
The Science of the total environment 2019 v.677 pp. 466-473
Hippoglossus hippoglossus, atomic absorption spectrometry, breast milk, cadmium, crabs, eating habits, fish consumption, food safety, infants, kidneys, lead, lean fish, liver, mercury, mothers, mussels, regression analysis, scallops, seafoods, variance
Mercury (Hg), cadmium (Cd), and lead (Pb) are of great concern for food safety and infants are especially sensitive to exposure to the maternal body burden. We quantified these elements in breast milk from Norwegian mothers and determined their association with dietary habits, maternal amalgam fillings, and smoking. Breast milk (n = 300) from the Norwegian Human Milk Study (HUMIS) was analyzed using triple quadrupole inductively coupled plasma mass spectrometry, after an acidic decomposition using microwave technique. We used multiple linear regression to examine predictors of Hg and Cd in breast milk, and logistic regression to test predictors of Pb above the quantification limit. The median breast milk concentrations (minimum - maximum) were 0.20 μg Hg/kg (<0.058–0.89), 0.057 μg Cd/kg (0.017–1.2), and <0.67 μg Pb/kg (<0.2–7.5). Cadmium showed no significant relation with any exposure variable investigated. Lead was associated with intake of liver and kidneys from game. For Hg concentration in breast milk, number of amalgam fillings and high fish consumption were significant predictors (p < 0.001). We detected a significant association (p < 0.01) between Hg in breast milk and maternal consumption of Atlantic halibut, lean fish, mussels and scallops and lifetime consumption of crab. Seafood intake alone explained 10% of variance, while together with amalgam explained 46% of variance in Hg concentration in breast milk. Our findings emphasize the importance of following consumer advice with respect to fish and seafood and points to amalgam as an important source for Hg exposure.