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Within the early 2000s, researchers examined breast milk samples from U.S. moms and located excessive ranges of poisonous compounds used as a standard flame retardant in home items.
The compounds, polybrominated diphenyl ethers (PBDEs), have been progressively phased out after a hyperlink was discovered with sure well being dangers. It seems like a public well being success story, however new analysis suggests it is probably not fairly that straightforward.
This summer season, scientists detected a brand new set of comparable flame retardants within the breast milk of fifty U.S. girls.
Brominated flame retardants — the category of compounds that features PBDEs and these new compounds — have been first developed within the Nineteen Seventies to forestall burning in family electronics and home equipment. As a result of they’re utilized in so many alternative merchandise, we are available in contact with these compounds in our every day lives, says Dr. Sheela Sathyanarayana, a professor of pediatrics and environmental well being on the College of Washington and Seattle Youngsters’s Analysis Institute who is without doubt one of the authors of this research.
Persons are uncovered to those flame retardants by means of mud and air. “Though it appears unusual, we truly ingest some quantity of mud day-after-day,” says Sathyanarayana, “simply from touching issues or mud touchdown on our meals or in our water.”
They’re additionally extraordinarily persistent chemical substances, which means when you’re uncovered to them, you’d seemingly have them in your physique for years since they do not break down simply.
PBDEs have been essentially the most well-known and extensively used compounds on this class of flame retardants — till scientists discovered them in breast milk and began elevating the alarm about their potential impression on human well being.
A 2015 report from the U.S. Division of Well being and Human Companies says that PBDE publicity in utero and infancy (through breast milk) could affect hormones within the physique, together with thyroid hormones, which play a key function in nervous system improvement. And proof suggests publicity is likely to be linked to developmental points in children.
“PBDEs have been related to opposed neurodevelopmental well being outcomes in kids when uncovered in utero,” says Sathyanarayana.
The Environmental Safety Company finally banned PBDEs from business use in 2009 after coming to an settlement with producers to section out most makes use of of PBDEs by the tip of 2013.
However regulation of poisonous chemical substances tends to ban chemical substances one by one, somewhat than a whole class of comparable compounds, says Sathyanarayana, so firms began utilizing substitutes that have been very comparable in construction and conduct to PBDEs.
On this new research, printed this summer season in Environmental Air pollution, researchers analyzed the breast milk of fifty U.S. moms within the Seattle space and detected a complete of 25 flame retardants, together with 16 substitute chemical substances and 9 phased-out PBDEs.
Of these substitute chemical substances, a kind of flame retardant often called bromophenols was present in 88% of samples. Bromophenols are comparable in construction to PBDEs in addition to the thyroid hormone and preliminary analysis reveals that, like PBDEs, they will have an effect on thyroid operate.
This research marks the primary investigation into exposures in breast milk since 2012, so whereas the pattern measurement is comparatively small, “that is an attention-grabbing begin that I hope will spur extra analysis,” says Sue Fenton, a reproductive endocrinologist at NIH’s Nationwide Institute of Environmental Well being Sciences.
The PBDEs that have been nonetheless detected “have been a lot decrease in focus than earlier years,” says Sathyanarayana. Given how lengthy PBDEs final within the setting and within the physique, “it isn’t too shocking that they have been nonetheless present in breast milk,” says Deborah Bennett, an publicity scientist and professor of environmental well being for the College of Medication at College of California, Davis.
Researchers say it is too early to know whether or not we must be fearful about these new bromophenols. “There’s not a lot data on developmental well being results of a number of of the bromophenols and [brominated flame retardants] thought of as ‘replacements,’ ” says Fenton. “There must be extra research initiated to higher perceive the roles of those rising contaminants.”
Sathyanarayana says she thinks they will discover comparable developments as they did with PBDEs, however echoes that there is not as a lot analysis out but.
The research checked out predominantly white, well-educated girls within the Seattle space, so Bennett is desirous about seeing if ranges of flame retardant compounds in lower-income populations are larger. “Oftentimes exposures are larger amongst low-income populations.”
Whereas researchers work to higher perceive the well being results of those new substitute flame retardants, states like New York and Washington, in addition to the European Union, have handed stricter rules and bans on the usage of the entire class of brominated flame retardants in digital merchandise. Sathyanarayana says that broader chemical class bans can be extra helpful than particular person chemical bans.
“When you regulate particular person chemical substances,” says Sathyanarayana, “what finally ends up taking place is that there are what have been referred to as ‘regrettable substitutes’ — substitutes which might be put into the marker that they assume are safer, however then we discover that they are simply as pervasive and should have simply the identical quantity of toxicity.”
Bennett stresses that whereas “we wish girls to have the ability to have breast milk that does not have any contaminants in it, breast milk stays the perfect for youngsters.”
Bec Roldan (they/them) is the 2023 AAAS Mass Media Science and Engineering Fellow at NPR. They’re a fifth 12 months Ph.D. candidate and science journalist.