Steel drinking straws may actually be safer and more eco-friendly than paper straws, with a new study warning potentially dangerous chemicals found in them mean they may not be better than plastic versions.
A new study by Belgian researchers, published on Friday (24 August) in the Food Additives and Contaminants journal, found “forever chemicals” - which can last for thousands of years in the environment and are potentially harmful to people and wildlife - in 18 out of 20 brands of paper straws tested.
The researchers analysed 39 brands of straws overall for a group of synthetic chemicals known as 'PFAS'. They were found in the majority of them, most commonly in those made from paper and bamboo.
This comes after a growing number of countries, including the UK and Belgium, banned the sale of an expanding range of single-use plastic products - including drinking straws - leading to paper versions becoming popular and cost-effective alternatives.
Thimo Groffen, an environmental scientist at the University of Antwerp, told PA his team wanted to find out if PFAS were in plant-based drinking straws sold in Belgium and Europe, after they were discovered in straws sold in the US.
The team bought 39 brands of drinking straw made from five materials – paper, bamboo, glass, stainless steel and plastic – mainly from shops, supermarkets and fast-food restaurants, before putting them through two rounds of testing.
The majority of the brands – 27 out of 39 (69%) – contained PFAS, with 18 different PFAS detected in total, with paper straws the worst offenders - with the chemicals detected in 90% of brands tested.
PFAS were also detected in four out of five brands of bamboo straw, three out of four of the plastic straw brands, and two out of five of the glass straws. They were not detected in any of the five types of steel straw.
The presence of the chemicals in almost every brand of paper straw means it is likely, in some cases, being used as a water-repellent coating, the researchers said.
“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," Dr Groffen said. “However, the presence of PFAS in these straws means that’s not necessarily true.”
The researchers believed the chemicals were likely being used as a water-repellent coating for the paper straws, but the study did not look at whether the PFAS were leaching out of the straws into liquids - although some of the varieties detected were at risk of doing that.
Scientists warned that while the PFAS concentrations were low and posed a limited risk to human health, PFAS could remain in the body for many years and build up over time.
The chemicals have been associated with a number of health problems including thyroid disease, increased cholesterol levels, liver damage, kidney cancer and testicular cancer.
Dr Groffen continued: “Small amounts of PFAS, while not harmful in themselves, can add to the chemical load already present in the body.
“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."