persistent chemicals Archives

August 15, 2024

Early exposure to toxic TCDF messes with gut bacteria later in life, finds study in mice

By Shannon Kelleher

Early-in-life exposure to a common toxic chemical found in some foods and in breastmilk may disrupt healthy bacteria in the gut and increase a person’s risk for developing various diseases later in life, according to a new animal study.

The findings, published Aug. 14 in the journal Environmental Health Perspectives, may shed light on the link between childhood exposure to persistent organic pollutants (POPs) and widespread obesity and diabetes in adults, according to the authors.

More than 460 million people worldwide have diabetes, while global obesity levels have tripled since 1975. One in three US adults and one in six children are considered obese, according to a 2023 report.

“This study emphasizes the importance of the microbiome as a key target of early life environmental pollutant exposure,” the paper states. Exposure to the children can occur before birth when pregnant women are exposed to the chemicals as well as after birth through breastfeeding.

Although previous research has identified correlations between exposure to POPs and obesity and type 2 diabetes, the microbiome’s role has not been clear, according to the study.

The researchers fed infant mice pills containing the chemical 2,3,7,8-tetrachlorodibenzofuran (TCDF) for five days, collecting data on their gut microbiomes right after the mice were fed the last dose and again three months later, when they had reached young adulthood. Compared to a control group that was not fed TCDF, the mice had higher body weight and glucose intolerance – a hallmark of diabetes – long after they ingested the chemical.

The researchers also measured lower levels of two bacteria species important for gut health in the mice fed TCDF when they were four months old, as well as markers of immune problems and inflammation in the intestines.

April 11, 2023

Banned carcinogen found in 88% of household objects, says new study

By Grace van Deelen

A banned chemical that potentially causes cancer in humans has been discovered in a wide array of household products, according to a study out today.

Short-chain chlorinated paraffins (SCCPs) are a group of chemicals that are used in metalworking and the production of PVC, plastics, rubbers, and other materials. They are persistent chemicals, meaning they don’t degrade in the environment and accumulate in animals. Chlorinated paraffins have been detected in various wildlife and in human milk and blood. The 2017 Stockholm Convention listed SCCPs under their Annex A, which urges the elimination of the chemicals. SCCPs were largely prohibited in Canada in 2013 and in the US in 2012.

A study published today in the journal Environmental Science: Processes & Impacts, shows that SCCPs are still widely present in household goods, indicating the need for more regulatory action. Researchers found SCCPs in 84 of 96 household goods tested in Canada. All the household goods were purchased at least one year after Canada’s prohibition of the chemical went into effect, suggesting that chemical regulation against SCCPs has not been entirely effective.

“We found [SCCPs] in almost everything, which was very surprising to us,” said Steven Kutarna, a PhD candidate at the University of Toronto and the lead author of the paper.