PFAS

PFAS, ‘forever chemical’ can be absorbed by the skin – The Conversation

The presence of synthetic chemicals, such as PFAS (per- and polyfluoroalkyl compounds), has been found everywhere. From polar bears in the Arctic to Tasmanian penguin colonies. They have even been detected in rainfall and ocean spray. The persistent chemicals were found in the blood of people from all over the globe, and in the breast milk. Our team has found them even in dust from , the International Space Station.

We still don’t know how PFAS enters our bodies. Ingestion (food, water, and other products containing PFAS), or breathing air contaminated by PFAS particles are possible pathways. Recent research indicates that PFAS can penetrate the skin of humans and enter their bloodstream.

Many consumer products contain PFAS, such as skin care products cosmetics, and clothing that is waterproof. The compounds are sometimes referred to by the term “forever chemicals”, due to their persistent nature in nature, and in our bodies where they can remain for years.

Dermal exposure, or the absorption of PFAS via the skin, could be a significant pathway for PFAS to enter the body. Our team of environmental scientists used 3D-models of lab grown human skin tissue to mimic the properties and characteristics of real human skin. They then investigated the dermal penetration (the uptake through the skin of a chemical) of 17 different chemicals.

Our results show that, contrary to previous beliefs, the skin can act as a barrier.

Experiments on 3D models were conducted using lab-grown human tissue. Oddny Ragnarsdottir CC-BY-ND

Once these chemicals are in our bodies, they can have a negative impact on our health. Some PFAS can disrupt hormone systems, and lower the immune response of children to vaccinations against diseases like diptheria. lower birth weights of newborns, and changes in the liver function are also concerning. The International Agency for Research on Cancer recently classified one PFAS, perfluorooctanoic acids or PFOA as “carcinogenic to human”.

In response, many Studies focused on quantifying the human exposure to PFAS. The most recent Research revealed that diet and drinking water are important routes of exposure.

In our study, 17 PFAS were selected that are already regulated in drinking waters. Our results shed light on the human exposure to 17 specific chemicals, but it is difficult to extrapolate these findings to other PFAS compounds because they have different properties and behaviors.

Short v long

Our results revealed that long-chained PFAS are not as readily absorbed through the skin as short-chained PFAS with fewer carbon atoms. By the end of a 36-hour period of exposure, 58% of an applied dose of perfluoropentanoic (a PFAS containing five carbon molecules) had been absorbed. For the most heavily regulated PFAS, PFOA, (a chemical containing eight carbons), 13% of applied dose permeated the skin in the same period.

The skin permeation of the PFASs included in this study also took time. As these compounds are present in everyday products, frequent exposure to them could result in significant exposure .

It was previously hypothesized that the PFASs we tested would absorb minimally under the conditions on the skin’s surface. Our study shows this is not true, since for eight of those tested PFASs, over 5% of their applied dose could fully penetrate through the skin and into the bloodstream. A substantial portion of the applied dose was found in the skin, which represents a reservoir for PFAS.

Our study allows us to better understand the importance of skin exposure to PFAS and which chemical structures are most readily absorbed. It is important to note that the industry has shifted towards chemicals with shorter chains because they are thought to be less toxic and less persistent.

The trade-off is that these shorter-chain PFAS are easier to transport through the skin barrier. Before bringing PFAS containing products to the market, manufacturers and regulators must be certain of the risks.