Matt is an environment correspondent.

uniformsImage source, Getty Images

High levels of "forever chemicals" are found in a study of school uniforms.

The chemicals used to make clothing resistant to stains and water have been linked to a number of health issues.

The uniforms made with cotton had higher levels than those made with synthetic materials.

The long-term health risk may be increased by exposing children to these chemicals.

In the UK, almost all retailers' own brand uniforms are free of PFCs.

Fire-fighting foams, food packaging, and textiles are just some of the uses of the non-stick and water- resistant chemicals.

Researchers have been worried about these chemicals because they don't break down under normal environmental conditions.

schoolImage source, Getty Images
Image caption, Around 20% of US and Canadian school children wear uniforms

There are many "forever chemicals" in the soil and water. They can accumulate in the body when eaten.

Scientists are concerned about the exposure of young people with low body weight and sensitive development who may be at greater risk of developing health problems.

The study focused on the contact with the chemicals that may occur when wearing school uniforms.

Around 20% of kids in the US and Canada wear uniforms in school.

"All of these clothes that we targeted are polo shirts and khaki pants, the usual uniforms, but they were specifically marketed as stain resistant," said Dr. Venier from Indiana University who led the study.

We picked clothes that were labeled as stain resistant. In all of the items, we found PFAS.

The researchers looked for fluorine levels in the products. The school uniforms had higher levels than the outdoor wear.

Synthetic products were more likely to contain more than cotton. Synthetic items have higher water and stain resistance, according to the scientists.

The researchers acknowledge that their study is small. The researchers don't know how the PFAS gets into children's bodies.

We are not toxicologists. We try not to go into areas that aren't ours.

PFASImage source, Getty Images
Image caption, PFAS are found in may locations including in rainwater in Tibet

She said that the idea that children in uniforms can release substances is a concern.

Some of the chemicals have been banned in the UK.

In the UK, an environmental charity leads a campaign to inform retailers about the presence of PFAS.

"We found that people that bought uniforms, with these coating, washed them more often, and replaced them just as much as people that didn't buy stain- resistant uniforms," said Dr Cavers.

After a few washes, the stain resistant coating came off. It was not making any difference if they were buying the uniform for that function.

All major retailers in the UK now sell their own brand school uniforms for free.

California will be the first state to end the sale of clothing and textiles made with PFAS. The EU is looking at a ban and the UK is looking at it.

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