Polyfluorinated alkyl substances (PFAS)

[edit] Introduction

Per- and polyfluorinated alkyl substances PFAS, are also known as Forever Chemicals, because of their persistent, bioaccumulative, and toxic (PBT) properties, some taking up to 1000 years to breakdown in natural environments.

[edit] Background

They are defined as substances containing at least one fully fluorinated methyl (CF3-) or methylene (-CF2-) carbon atom (without any H/Cl/Br/I atom attached to it), examples include perfluorooctanoic acid (PFOA), perfluorooctane sulfonate or perfluorooctane sulfonic acid (PFOS), perfluorinated carboxylic acids and polytetrafluoroethylene (PTFE) or Teflon.

First created in the 1940's, there are more than 4,000 examples of these synthesised chemicals present in a wide range of different products. They are highly resistant to chemical and thermal breakdown as well as repelling water and oil. They are colourless, tasteless and odourless. Since the mid 1900's they have been used to produce many household and industrial products from non-stick frying pans to waterproof jackets, flame retardants and stain sealants for interior furnishings and fabrics, and cosmetic make-up, grease-resistant paper, food containers, wrappers and packaging, paints, varnishes, sealants, and finally cleaning products, shampoos and dental floss.

[edit] Risks

The effects of high level exposure to PFAS's include increased risk of cancer, kidney disease, reproductive and developmental disruption as well as impacting vaccine response. Research suggests exposure to PFOA and PFOS from today’s consumer products is usually low, especially when compared to exposure to contaminated drinking water. Based on the available data, only a small amount of PFAS can get into the body from skin contacting PFAS-contaminated water

Most PFAS do not evaporate into the air from water readily, therefore, for most PFAS, showering, bathing, or washing dishes in water containing PFAS should not increase exposure. Routes to exposure are; drinking contaminated municipal water or private well water, eating fish caught from water contaminated by PFAS (PFOS, in particular), accidentally swallowing contaminated soil or dust, eating food grown or raised near places that used or made PFAS, eating food packaged in material that contains PFAS, using some consumer products such as stain resistant carpeting and water repellent clothing.

[edit] Action

On January 13, 2023 Germany, Denmark, Netherlands, Norway and Sweden submitted a request for restrictions to be placed on the manufacture, placing on the market and use of PFAS. In the US in August, 2022, EPA issued a proposal to designate two of the most widely used PFAS as hazardous substances under CERCLA and in November 2022, EPA released a report documenting the Agency’s first year of progress under its PFAS Strategic Roadmap.

The OECD definition of PFAS (2021) reads: “PFASs are defined as fluorinated substances that contain at least one fully fluorinated methyl or methylene carbon atom (without any H/Cl/Br/I atom attached to it), i.e. with a few noted exceptions, any chemical with at least a perfluorinated methyl group (–CF3) or a perfluorinated methylene group (–CF2–) is a PFAS.” [OECD. Series on Risk Management No. 61, 2021]. Substances meeting the chemical scope definition for this restriction proposal will therefore also meet the OECD PFAS definition.

The submission for to the European union for market restrictions reads; "PFAS are, or ultimately transform into, persistent substances, leading to irreversible environmental exposure and accumulation. Due to their water solubility and mobility, contamination of surface, ground- and drinking water and soil has occurred in the EU as well as globally and will continue. It has been proven very difficult and extremely costly to remove PFAS when released to the environment. In addition, some PFAS have been documented as toxic and/or bio-accumulative substances, both with respect to human health as well as the environment. Without taking action, their concentrations will continue to increase, and their toxic and polluting effects will be difficult to reverse."

[edit] GenX

GenX chemicals were developed as replacements for PFOA (part of the group of PFAS) for manufacturing fluoropolymers, including Teflo, since the original compounds were found to be toxic and carcinogenic, therefore banned. However, the replacement chemical GenX has also been shown to cause many of the same health problems as PFOA, with the EPA's toxicity assessment concluding that oral ingestion has potential adverse health effects on the hepatic, hematological, renal, reproductive, and immune systems and linked to liver and pancreatic cancer.

PFOA was banned globally under the Stockholm Convention in 2019, but was voluntarily phased out by manufacturers in Europe and the US over the preceeding decade. The chemical industry developed GenX as a replacement technology for PFOA, based on other members of the PFAS group. This alternative was presented by the industry as having a “more favorable toxicological profile”. Howeve rin 2019 EU experts voted unanimously in favour of adding GenX chemicals to the EU list of substances of very high concern (SHVC), which is a first step in increasing regulatory controls over them.

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