Paper straws, which are being pushed across the U.S. as an eco-friendly alternative to plastic versions, may contain "forever chemicals" that are harmful to both humans and the environment and were observed more often than in a sample of plastic straws, a new European study has found.
Belgian researchers tested 39 straw brands from restaurants and retailers for synthetic chemicals known as poly and perfluoroalkyl substances (PFAS). The study found that the majority of straws contained those chemicals, but they were most common in those made from paper and bamboo.
The chemicals are referred to as "forever chemicals" as they can remain for thousands of years in the environment. The chemicals have been associated with health issues including thyroid disease, increased cholesterol, liver damage and kidney and testicular cancer and can harm the environment as well.
Of the brands tested, 90% of the paper straws contained PFAS, compared to 80% of bamboo straws, 75% of plastic straws and 40% of glass straws. None of the steel straws contained the chemicals.
The study was published in the peer-reviewed journal Food Additives and Contaminants.
Researchers stressed that PFAS concentration was low and pose a limited risk to health, given that people use such straws only occasionally. But they can remain in the body for years, and concentrations can build up, they said in a release.
"Straws made from plant-based materials, such as paper and bamboo, are often advertised as being more sustainable and eco-friendly than those made from plastic," researcher Dr Thimo Groffen, an environmental scientist at the University of Antwerp, said in a statement.
"However, the presence of PFAS in these straws means that’s not necessarily true."
It wasn’t clear whether the chemicals were added by manufacturers or occurred due to contamination from soil and water during manufacturing. The study did not look into whether the straws could contaminate liquids.
"The presence of PFAS in paper and bamboo straws shows that they are not necessarily biodegradable," Groffen said. "We did not detect any PFAS in stainless steel straws, so I would advise consumers to use this type of straw – or just avoid using straws at all."
The study comes as European countries, and some parts of the U.S., have pushed to transition away from plastic straws to alternatives in efforts to be more environmentally friendly. States including California and New York have slapped bans on single-use plastic straws in restaurants.