Perfluorinated alkyl substances in Canadian human milk as part of the Maternal-Infant Research on Environmental
Dorothea F K Rawn1, Guy Dufresne2, Geneviève Clément2
1Food Research Division, Bureau of Chemical Safety, Health Products and Food Branch, Health Canada, Sir Frederick Banting Research Centre, 251 Sir Frederick Banting Driveway, Address Locator: 2203C, Tunney's Pasture, Ottawa, ON K1A 0K9, Canada.
Abstract:
Perfluorinated alkyl substances (PFAS) were determined in human milk samples (n = 664) from participants in the Maternal-Infant Research on Environmental Chemicals (MIREC) study. ΣPFAS concentrations (sum of seven PFAS) ranged from 3.1 ng L-1 to 603 ng L-1, with a median concentration of 106 ng L-1 in the Canadian mothers' milk analyzed. These data comprise the first pan-Canadian dataset of PFAS in human milk. Perfluorooctanoic acid (PFOA) and linear perfluorooctanesulfonate (L-PFOS) were the dominant contributors to ΣPFAS in human milk samples. An inverse relationship between ΣPFAS concentrations and age was observed (Spearman correlation - 0.184). Primiparous women had elevated PFAS concentrations in milk relative to women who had children previously (p < 0.001). In contrast, the region of maternal birth did not influence ΣPFAS concentrations (p = 0.156). Although China and Norway have observed consistently detectable levels of perfluoroundecanoic acid (PFUdA) in human milk, PFAS with long carbon chains (n ≥ 11) were not present above method detection limits in Canadian human milk samples analyzed as part of the MIREC study. In conclusion, despite the presence of low levels of environmental contaminants in human milk, Health Canada supports breastfeeding due to the benefits to both infants and mothers.
