Legacy halogenated flame retardants in Canadian human milk from the maternal-infant research on environmental chemicals study.

Dorothea FK Rawn, Amy R Sadler, Valerie A Casey, François Breton, Wing-Fung Sun, Sherry Yu Feng, Tye E Arbuckle. Journal of Environmental Exposure Assessment. 2024; 3(3): 16. http://dx.doi.org/10.20517/jeea.2024.04

Question: Why are legacy flame retardants measured in human milk in Canada? They are groups of chemicals used in numerous consumer products found in homes and workplaces to reduce their flammability. They are now known to persist in the environment and to accumulate in the fatty tissue of humans; as a result, their manufacture is now banned and their use is restricted in Canada.

What did the researchers do:
At a Health Canada lab, researchers measured concentrations of several persistent flame retardants in 298 human milk samples collected during the MIREC study (2008 and 2011). They then compared concentrations by characteristics of the women.

What did they find:
The polybrominated diphenyl ether (PBDEs) flame retardants were detected in all of the milk samples; however, the concentrations have declined slightly since the early 2000’s. Hexabromocyclododecane (HBCD) was measured in 94% of the milk samples and concentrations have also decreased since the early 2000’s. Concentrations of these chemicals didn’t differ by the age of the mother. Similarly, the number of children a woman has had, pre-pregnancy body mass index (BMI), or education level were not associated with concentrations of these brominated flame retardants.

What does this mean:
In July 2008, Canada introduced regulations preventing the manufacture and restricting the use of these legacy flame retardants, thereby minimizing their release into the environment. Levels of these persistent brominated flame retardants in human milk are now declining. Despite these chemicals being present in Canadian human milk, Health Canada supports continued breastfeeding because of the important health benefits for both the mothers and their infants.

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