Per- and polyfluoroalkyl substances (PFAS) have become ubiquitous throughout the environment, and increasing evidence has demonstrated their deleterious effects. A group of smaller, fluorinated compounds are becoming replacements for these “forever chemicals,” though research suggests the smaller versions could also be harmful. Now, a study in the American Chemical Society’s (ACS’) Environmental Science & Technology reports that the levels of these substances in many indoor and human samples are similar to or higher than those of legacy PFAS.
Though PFAS are widely used in consumer goods, including food packaging, period products, and toilet paper, some governments are beginning to regulate their use. The most common are PFOS and PFOA—they are composed of eight-carbon-long backbones and are considered to be perfluoroalkyl acids (PFAAs).
“Short-chain” PFAAs, containing fewer than eight carbons, and “ultrashort-chain” PFAAs, with just two to three carbon atoms, have been thought to be suitable replacements for PFOS and PFOA. However, recent research has shown that their small size makes it easy for them to move throughout water supplies, and in vitro and in vivo tests have suggested that they could be more toxic than the longer compounds.
How was PFAS measured in this study?
Researchers collected over 300 samples of dust, drinking water, serum, and urine from 81 people and their homes in the US and analyzed them for 47 different PFAAs and their precursors. Of these fluorinated compounds, 39 were detected, including ultra-short and short-chain compounds.
PFOS and PFOA were frequently detected in dust, drinking water, and serum, but were less abundant than the shorter-chain PFAAs.
In most dust, drinking water, and serum samples, two-carbon-long trifluoroacetic acid was the most predominant PFAA, often followed by three-carbon-long perfluoropropanoic acid.
In urine samples, the five-carbon long perfluoropentanoic acid was the most abundant PFAA present.
The researchers explain that the smaller PFAAs could slip through filters into drinking water or accumulate easily in household dust. Interestingly, dust samples from homes without carpets and homes that were vacuumed regularly contained substantially lower levels of PFAAs. From the data, the team determined that dust and water intake contributed only about 20 percent of the total PFAA burden in these cases.
This result suggests that these compounds must originate from other sources—many PFAA precursors can be found in consumer products; some evidence suggests that they can break down into shorter-chain compounds in the environment or the body. The researchers say that further investigation into ultra-short PFAA levels, their sources, and their effects on human health is needed.
- This press release is supported by the American Chemical Society