PFAS substances have been used in a huge range of industrial and commercial products spanning more than 100 sectors, thanks to their thermal and chemical stability. Some of the most common applications include pesticide formulation, firefighting foams, cosmetics, aerospace, aviation, automotive, textiles coating, oil production, medical products, food processing, building and construction, energy, paper and packaging, cables and wiring, electronic and semiconductors. However, the waste and degradation of these products we are all reliant upon, and use daily, has meant PFAS leached into the environment.
A schematic representation of PFAS emission sources is shown in the figure created by Panieri et al., 2022 in their paper titled 'PFAS Molecules: A Major Concern for the Human Health and the Environment'.
PFAS move around in the environment, present in high levels in soils, waterways and even the air. One of their most concerning properties is their biomagnification up the food chain, meaning those at the top will receive the highest doses. This can manifest itself in the short and long term exposure of aquatic ecosystems, terrestrial ecosystems and humans to PFAS substances, that can also enter into the food chain through bioaccumulation and indirect human exposure via the ingestion of contaminated food sources.
When chemicals are detected at 100 ng or more per litre, water companies are under instruction to immediately act on the contamination. In the U.K. and Europe, around 1000 sites contained over 1,000 ng per litre, while 300 sites showed concentrations at 10,000 ng per litre. The highest concentrations in the U.K. were mapped at the River Wyre in Blackpool, where flounder in the river were found to contain up to 11,000ng/kg, according to data from Defra’s Centre for Environment, Fisheries and Aquaculture Science. PFAS leach down into groundwater used for drinking water. Water used used for livestock or spraying crops is often not treated, allowing PFAS to enter the food chain. While water is treated for human consumption, not all PFAS are currently able to be removed before reaching our taps and the post-treatment waste PFAS also still need to be disposed somewhere. Even blank spaces on the map are not free from PFAS, but likely have just not been tested yet due to sampling biases toward the areas that surround environmental agencies.
Their ubiquitous distribution, extreme persistence and bioaccumulation potential have unfortunately become a crisis since these chemicals have been linked to major health issues in humans and wildlife. PFAS have been linked to high cholesterol, ulcerative colitis, thyroid disease, testicular cancer, kidney cancer, pregnancy induced hyper tension , birth defects, low birth weight and more. Exposure to PFAS during early pregnancy has additionally been linked to the child having a lower sperm count, showing disruption of normal hormone functioning and development, and showcasing PFAS as an inter-generational issue.
As always, science is catching up to destroy the 'indestructible' chemicals already present in the environment. Early attempts include heating water until it becomes supercritical: it is neither a gas nor a liquid. In this state, even water-repellent substances such as PFASs dissolve much more readily, and at the same time, the state accelerates chemical reactions. Three versions of this technique trialled in a study led by EPA researcher Max J. Krause, removed 99 percent of PFASs in the water. Krause is optimistic that this can be deployed at a wide scale as "supercritical water oxidation systems are already commercially available, this may be a technology that could soon be deployed for significantly impacted sites or wastewaters". It remains to be seen whether these techniques can be scaled up to a watershed or even a drinking water treatment facility, and does not address those PFAS present in the soil and atmosphere. While solutions are still being sought, the most important step to preventing the crisis from worsening is to stop PFAS at the source. Many companies have now made statements to distance themselves from PFAS use, and PFAS producing companies are diversifying away into alternatives. It is our job to educate ourselves on our consumption choices, and to pressure those companies and products still reliant on PFAS to change course.