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PFOA (Penta-decafluoro-octanoic acid), its salts and PFOA-related compounds fall within a family of perfluoroalkyl and polyfluoroalkyl substances (PFASs). PFASs consist of carbon chains of different lengths where the hydrogen atoms are completely (perfluorinated) or partly (polyfluorinated) substituted by fluorine atoms.
The very stable bond between carbon and fluorine is only breakable with high energy input. Therefore, perfluorinated acids such as PFOA are not degradable in the environment. Certain polyfluorinated substances can be degraded to persistent perfluorinated substances such as PFOA under environmental conditions and are therefore precursors. Those PFASs, which can be degraded to PFOA in the environment, are referred to as PFOA-related compounds.
For the purposes of the risk profile of the UNEP report for the Stockholm Convention on Persistent Organic Pollutants (2016)1, PFOA-related compounds are any substances that degrade to PFOA, including any substances (including salts and polymers) having certain linear or branched perfluoroheptyl group as one of the structural elements.
1 Stockholm Convention on Persistent Organic Pollutants UNEP/POPS/POPRC.12/11/Add.2 Pentadecafluorooctanoic acid (PFOA, Perfluorooctanoic acid), its salts and PFOA-related compounds RISK PROFILE - Persistent Organic Pollutants Review Committee
The uses of PFOA and PFOA-related substances are widespread and consumer articles and mixtures containing these substances are placed on the market in all EU Member States and worldwide.
PFOA and its salts are most widely used as processing aids in the production of fluoro-elastomers and fluoropolymers, with PTFE being an important fluoropolymer. PFOA-related compounds are used as surfactant and for the manufacture of side-chain fluorinated polymers. Due to the surfactant properties of both PFOA and its related non-polymeric surfactants, applications exist for the use of these substances, e.g. fire-fighting foams, wetting agents and cleaners. Side-chain fluorinated polymers provide durable water, oil and stain repellence and find use as surface finishes for textiles and apparel, leather, paper and cardboard, paints, lacquers and other uses (non-woven medical garments, floor waxes, and stone/wood sealants, thread sealant tapes and pastes, adhesives, products for apparel).
In relation to previous regulatory restriction measures and voluntary initiatives by some producers or users, these uses have been observed to progressively decrease over time and reasonable estimates of environmental emissions are currently in the order of a few tonnes per year. However PFOA-related substances are used in quantities, which are orders of magnitude greater than PFOA itself, and are therefore of considerable interest. An assessment of the significance of PFOA-related substances to the overall environmental load of PFOA requires an understanding of both the proportion of parent substance that is likely to transform to PFOA in the environment (yield as % or mol %), and information on how rapidly this could occur (for example, over a period of months, years or decades).
In particular, eight major leading companies in the per- and polyfluoroalkyl substances industry met the two goals of the global PFOA Stewardship Program set by the US-EPA in 20062:
PFOA, its salts and PFOA-related compounds are already subject to a number of national regulations and to the Oslo/Paris Commission for the Protection of Marine Environment of the North-East Atlantic (OSPAR). In particular in the E.U., PFOA was included under the Classification, Labelling and Packaging (CLP) Regulation (Regulation (EC) No 1272/2008).
PFOA is identified as a substance of very high concern because:
The E.U. Member State Committee RAC on PFOA3 concluded that all degradation results show that PFOA is indeed persistent and does not undergo any abiotic or biotic degradation under relevant environmental conditions. There is also evidence, according to this report, that PFOA has a low to moderate potential to accumulate in aquatic (i.e. water breathing) species, but there is evidence that PFOA and its salts accumulate and biomagnify in air-breathing terrestrial and marine mammals (BMFs, TMFs > 1).
PFOA was found in the blood of the general public with a half-life of approximately 4 years and as PFOA is a PBT substance, it is not possible to establish a safe level of exposure and therefore emissions of PFOA are to be minimised.
The fact that PFOA is a highly persistent substance ubiquitous in the environment and in humans, with a potential for environmental long-range transport, makes emission of PFOA and PFOA-related substances a transboundary pollution problem. The uses of PFOA and PFOA-related substances are indeed wide-dispersive as consumer articles and mixtures containing these substances are placed on the market. Evidence from contaminated sites showed that it is very difficult to reduce the level of pollution once it has occurred.
The UNEP report concluded that PFOA, its salts and related compounds that degrade to PFOA are likely, as a result of their long-range environmental transport, to lead to significant adverse human health and/or environmental effects, such that global action is warranted.
Only additional regulation of the PFOA-related substances will serve to decrease PFOA concentrations in the environment and humans both in the short and the long-term.
The aim of the proposed restriction is to stop all intentional use of PFOA and PFOA-related substances, with the only remaining sources being due to the presence of PFOA and PFOA related impurities below the threshold(s) set in the proposal as well as products still in use (and existing uses for which substitution is not technically feasible).
The EU Risk Assessment Committee cannot assess to what extent use of PFOA and PFOA-related substances outside the EU contributes to pollution within the EU, but recognised that global efforts may be required to reduce the long-range transport of PFOA to Europe. Therefore, any national regulatory action cannot alone, adequately minimize emissions of PFOA and PFOA-related substances. As a consequence risk management action is needed on an EU wide basis.
A restriction covering all emission sources is considered to be the most appropriate EU wide measure that can effectively reduce emissions of PFOA and PFOA-related substances.
3 EU Committee for Risk Assessment (RAC) and Committee for
Socio-economic Analysis (SEAC)
https://echa.europa.eu/documents/10162/13641/rest_pfoa_compiled_opinions_en.pdf/2f0dfce0-3dcf-4398-8d6b-2e59c86446be
The direct use of PFOA is mainly limited to be a processing aid for the polymerisation of fluoropolymers. For the RAC-SEAC report, the groups of PFOA-related substances of greatest concern are fluoro-telomers and sidechain fluorinated polymers such as polytetrafluoroethylene (PTFE), which are used in fire-fighting foams, grease-resistant food packaging, leather protectants and stain-resistant carpeting and textiles. Consumer products for which PFOA-APFO is used in their production include non-stick (PTFE-coated) cookware and kitchen utensils, flexible inlays for frying pans, tread sealant and tape, apparel membranes, dental floss and tape, some types of tubing.
There is a voluntary commitment among some producers to stop using C-8 chemistry (including PFOA and the PFOA-related substances), which most likely will reduce emissions over time. However, this commitment does not cover all producers and clearly not the importers of treated textiles, which are considered to be a major source of PFOA to the environment.
The use areas of biggest concern when it comes to potential EU emissions of PFOA are (imported) textiles and firefighting foams and the RAC – SEAC report concluded that a regulation of only PFOA itself would thus be rather meaningless as a measure to decrease the environmental burden of PFOA. In contrast, the use in semiconductor and photographic applications seems rather marginal, and little is known about the use in paints and inks, even if PFOA-based paints could potentially be an important source of emissions to the environment during their application and service life.
Emissions could potentially occur at every stage in the life cycle, i.e. during production, service life and disposal. EU wide action is therefore necessary to eliminate emissions of PFOA and PFOA-related substances. According to the UNEP report (2016), direct releases to the environment occur from the production of the raw substance (including PFOA as impurity in the manufacturing of PFOA-related compounds and some alternatives), during the processing, use and disposal of the chemical, from treated articles and from products contaminated with PFOA. Main emission vectors of PFOA and its salts are water, wastewater and dust particles.
Worldwide monitoring of water, air, sediment and biota at remote locations all detect the presence of PFOA and related compounds. Environmental modelling data also suggested that the capacity for long-range transport does exist.
Important potential sources of PFOA are considered to be the use of side-chain fluorinated polymers in general, and specifically their use in the textile sector. PFOA-related compounds have the capacity to degrade to PFOA in the natural environment contributing to the environmental concentrations of PFOA. An assessment of sources of PFOA to the Baltic Sea estimated that 30% of the releases were due to transformation of fluorotelomers. Based on the available information on transformation, all PFOA-related substances (which might also be present as monomers/impurities in some substances including polymers) seem to degrade to PFOA in amounts >0.1% per year. The quantities of PFOA generated via degradation from PFOA-related compounds quoted by ECHA are more debatable, with values between 1.7% and 40%. There was no information provided in the public consultation on the draft RAC-SEAC report showing that there are substances with linear or branched perfluoroheptyl- or perfluorooctyl derivatives (beside the exceptions defined in the proposal) that cannot degrade or be transformed into PFOA.
Other important sources appear to be coatings and firefighting foam. Based on the available information, it is not possible to definitively identify specific uses or PFOA-related substances that will not contribute to PFOA emissions, but PFOA emissions from photographic applications and from the semiconductor industry appear to be less than 100 kg/year for the whole EU (and therefore create a lower risk in relative terms).
The UNEP report mentioned an US EPA reference describing releases to the indoor domestic environment that arose from the use of products containing PFOA and its related compounds for several products purchased from retail in the US. The largest releases from use reported were for professional carpet-care liquids, pre-treated carpeting, floor waxes and stone/tile/wood sealers, and household textiles and upholstery.
In addition, an indirect risk to the general public exists because of potential long-term effects on the food chain arising from the PBT properties of the substance.
The RAC report concluded that environmental emissions (and hence risks, due to the PBT properties) of PFOA can arise from direct uses, from the presence of PFOA as an unintentional impurity in a wide variety of other substances (including polymers that are made with PFOA as a processing aid), and from the degradation of PFOA-related substances.
Therefore releases of PFOA from degradation contribute a major share to the releases of PFOA to the environment, and these are emissions relevant to inclusion in the proposed restriction. The RAC-SEAC report assumed an overall environmental transformation of 1% per year of the fluorotelomer-based polymers into PFOA recognising that this might be an over-estimate for some types. It is difficult to predict confidently which specific uses contribute most to the risk, especially as there is such a diverse range of potential sources, and detailed information about most of them is lacking.
In conclusion the report recommended that the proposed restriction should encompass an open-ended list of PFOA-related substances, similar to the current EU restriction of PFOS.
PFOA exposure of the general public typically takes place “human via environment” by consumption of drinking water and food including breast feeding, via uptake of contaminated indoor air and dust, or from consumer products containing PFOA, its salts and related compounds. PFOA has been detected in human blood and breast milk. Humans are very slow eliminators of PFOA compared with other species with an estimated half-life of PFOA elimination ranging from 2 to 4 years. PFOA accumulates in humans with increasing levels with age.
PFOA is quickly absorbed, it is not metabolised and is distributed in the body, then can be transferred to foetus through placenta and to infants via breast milk. A considerable number of adverse health effects associated with PFOA exposure in humans have been reported. There was a probable link to PFOA exposure for diagnosed high cholesterol, ulcerative colitis, thyroid disease, testicular cancer, kidney cancer and pregnancy-induced hypertension.
The American Cancer Society4 mentioned that studies have suggested an increased risk of testicular cancer with increased PFOA exposure in people living near or working in chemical plants. Studies have also suggested possible links to kidney cancer and thyroid cancer, but the increases in risk have been small and could have been due to chance. The EPA’s Scientific Advisory stated that there is “suggestive evidence of carcinogenicity, but not sufficient to assess human carcinogenic potential.” Nevertheless, the International Agency for Research on Cancer (IARC), part of the World Health Organization (WHO) classified PFOA as “possibly carcinogenic to humans” (Group 2B), based on limited evidence in humans that it can cause testicular and kidney cancer, and on limited evidence in laboratory animals.
Other studies have suggested possible links to other cancers, including prostate, bladder, and ovarian cancer. But not all studies have found such links and more research is needed to clarify these findings. Data have also demonstrated reproductive or developmental effects, endocrine disruption, impaired neurodevelopment, and immunotoxicity (primarily suppression of antibody response) associated with PFOA exposure in humans
On this basis in the European Union, PFOA has a legally-binding classification as carcinogen (category 2) and reprotoxic (category 1B).
According to the RAC report however, there is a potential concern for workers at fluoropolymer production sites based on limited monitoring data and the animal studies that indicated adverse developmental effects. There is no information about whether these monitoring data represent current worker exposures at such sites. RAC supported thus the use of a modified “derived no effect level” (DNEL) of 1600 ng/mL serum for the worker protection.
For the general population, using an intra-species safety factor of 10, the corresponding DNEL is 800 ng/mL serum. A DNEL cannot be reliably derived for some effects (e.g. on the mammary gland) that may be more sensitive than the animal data currently used in the risk characterisation. In the meantime, on the basis of existing data, the current level of knowledge and the present risk characterisation available, health risks for the general human population have not been identified due to direct toxic effects of PFOA.
However, according to the E.U. 2010 report, on the basis of various studies and reports, although residues of PFOA in consumer articles can be detected, potential exposure to PFOA from consumer articles is considered to be negligible.
4 American Cancer Society 2015. Teflon and Perfluorooctanoic Acid (PFOA)
https://www.cancer.org/cancer/cancer-causes/teflon-and-perfluorooctanoic-acid-pfoa.html
An earlier E.U. 2010 report5 had concluded that there seems to be no risk for the aquatic, terrestrial and atmospheric compartments. No risk could be identified for the microbial activity in sewage treatment systems. This report recommended that more research was done on the precursors of PFOA and more efforts made to gather information on international level, using the available information of the various international bodies, in order to come to an internationally/globally recognised list of precursor substances.
Environment Canada and Health Canada (2012) concluded that the risk (the ratio between the predicted environmental concentrations and the predicted no-effect concentration (PEC/PNEC ratio) indicated low likelihood of risk to pelagic organisms, mammalian wildlife from exposures at current concentrations in the environment even if, according to the ECHA (2014), cited in the UNEP report, the properties of persistent, bioaccumulative, and toxic (PBT) chemicals create uncertainty in the risk estimation to the environment and human health when performing quantitative risk assessment.
Nevertheless, the 2015 RAC report indicated that although PFOA exhibits low acute toxicity in aquatic organisms, it has the potential to affect endocrine function where visible effects may not be apparent until the organisms reach adulthood. In fish, PFOA inhibited expression of genes involved in thyroid hormone biosynthesis, induced vitellogenin gene expression, developed oocytes in the testes of males and caused ovary degeneration in females.
5 “Analysis of the risks arising from the industrial use of Perfuorooctanoic acid (PFOA) and Ammonium Perfluorooctanoate (APFO) and from their use in consumer articles.
For drinking water, in 2009, the EPA released provisional health advisories (PHAs) for PFOA and PFOS, which recommended actions to reduce exposure when contamination reaches 0.4 µg/L for PFOA and 0.2 µg/L for PFOS.
For PFOA-related substances, including side-chain polymers, in all mixtures and articles, RAC would favour a limit of contamination of 25 ppb for PFOA and 1000 ppb [1 ppm] with a derogation for C-6 fluorochemicals as transported isolated intermediates for further processing, provided that they are transported and used under strictly controlled conditions. Indeed, RAC believed that a very low threshold limit (such as 2 ppb) is likely to give rise to significant problems in implementation which may potentially lead to false positive tests.
The Committee for Socio-economic Analysis SEAC agreed with the RAC conclusions and noted that setting a low threshold limit value could put the EU industry under a competitive disadvantage in relation to non-EU manufacturers.
Some respondents to the public consultation about the RAC – SEAC report have suggested the use of certification to identify fluoropolymers made without the intentional use of PFOA (or possibly PFOA-related substances), mainly to avoid chemical analysis, which could be costly. Certificates could, be a good additional voluntary measure to help demonstrate compliance and promote the use of fluoropolymers made without PFOA.
The main alternatives to the use of PFOA are shorter-chain length fluorinated substances with less than seven fully fluorinated carbon atoms, i.e C-4 or C-6 fluorochemicals. As a polymerisation aid in polymer production, PFOA has been substituted with C3nDimers, which contain ether linkages between short fluorinated chains, which theoretically result in degradation to very short (≤ C-3) fluorinated compounds.
Non-fluorine containing substances are available for some applications, but they may be less efficient in some situations. Generally speaking, RAC agreed that the alternatives (including the shorter-chain length fluorinated substances) would currently appear to have hazard profiles of lesser concern than PFOA, with a lower potential for bioaccumulation and lower (eco)toxicity.
RAC noted the lack of comprehensive studies on the ‘PBT’-properties of the shorter chain length fluorinated substances and the alternative substances (including their degradation products). Overall, RAC considered that, based on the available information, the identified substitutes seemed to be of lower environmental concern than PFOA.
The restriction proposal includes ‘PFOA-related substances’, i.e. substances that, based on their molecular structure, are considered to have the potential to degrade or be transformed to PFOA. For example, side-chain fluorinated polymers as they are consistent with the definition of a PFOA-related substance. This proposal based on the PBT properties of PFOA should effectively captures the substances considered to be of concern, but excludes those that are not. As no relevant quantitative environmental risk assessment can as such be conducted for PBT substances, the overall intention is to minimise emissions. As supporting information, the restriction proposal also contains a quantitative risk assessment for human health but limited to specific uses.
The proposed restriction is similar to the previous restriction on PFOS, which has been shown to be very effective, but the PFOA proposal has much lower concentration limits. The most effective way to enforce this restriction is to target articles and mixtures. Since the proposed restriction is in line with the US-EPA stewardship program (see answer to question 3), some companies have already taken action to phase out PFOA and related substances by 2015, indicating that the restriction in general is applicable in practice.
Overall, SEAC considered that the costs of the proposed restriction were underestimated but agreed that the results correctly estimated the order of magnitude of the actual costs. Even if SEAC has not been able to establish a benchmark (range) of proportionate costs to reduce emissions of PBT/vPvB substances, taking into account the estimated cost-effectiveness and qualitative arguments provided, SEAC concluded that the proposed restriction, with the recommended changes in concentration limits, scope (derogations) and transitional periods, was proportionate.
RAC considered specific derogations for use in implantable medical devices, photographic and semiconductor (photoresist/photolithography processes) applications and for substances (covering C-6 fluorochemicals) used as transported isolated intermediates for further processing, provided that they are transported and used under strictly controlled conditions.
Possible other derogations were requested for a series of applications6, and SEAC supported the addition of derogations for semiconductor photolithography processes, photographic coatings applied to films, papers or printing plates, implantable medical devices, the use of substances as transported isolated intermediates (to allow the production of C6-based alternatives), and the placing on the market of spare parts.
Regarding in particular fluoropolymers, the objective of the proposal is to restrict the placing on the market, import, and use of fluoropolymers manufactured with PFOA, while allowing the use of the same fluoropolymers when they are not manufactured with PFOA. The fluorine chemical industry requested an exemption for “fluoropolymers manufactured without PFOA” and proposed a certification scheme to guarantee that they use such fluoropolymers all along the supply chain. However, SEAC did not agree to derogate fluoropolymers manufactured without PFOA and considered that, with the concentration limits suggested by RAC, such derogation should be not necessary.
Regarding firefighting foams already placed on the market, SEAC proposed to derogate them before the entry into force of the restriction, because replacement of all foams containing PFOA or PFOA-related substances will incur high costs over a relatively short period. Significant and defined volume of firefighting foams is kept stored on industrial sites to supply mandatorily required fixed installed fire protection systems or as an emergency stock in moveable large volume containments (trailers, skids, etc.). SEAC proposed to derogate in these applications future mixtures of restricted new foams with existing foams (exempted from the proposal) for 20 years, the normal lifetime for firefighting foams.
However, it is unsure that fluorine-free foams can be used in all situations and are compatible with all practice and strategies to combat fires across all firefighting services in the EU. SEAC proposed to adopt the higher concentration limit of 1 000 ppb per substance for both PFOA or for each PFOA-related substance when used in firefighting foam concentrates and to reconsider this concentration limit with an aim to lower it in the proposed review of the restriction 5 years after entry into force.
Regarding textiles used for worker’s protection, given the critical human health / life protecting functions of the C8 chemicals and the cost and effectiveness of substitution by C6 chemicals, SEAC proposed an extended transitional period of 6 years after entry into force for textiles for the protection of workers from risks to their health and safety.
For medical textiles, SEAC supported in particular an extended transitional period of 6 years for membranes intended for medical textiles, filtration in water treatment, production processes, and effluent treatment, and to reconsider this in light of technological development in the context of the review after 5 years of the entry into force with an aim to lower it in the future.
For implantable medical devices, photographic and semi-conductor (photoresist or photolithography) applications RAC can support derogations based on seemingly negligible emission potentials from these uses.
6 Those requests included Nano-coatings, Spare parts for automobiles, aviation, telecommunication, semiconductors, ICT industry, Cookware, Electrical monitoring and control instruments used in industries, Lithium ion battery technologies, Photolithography and etching processes in the semi-conductor industries, Photographic coatings applied to films, papers, or printing plates, Textiles and clothing products, Medical devices, Latex printing inks, Paper industry (papers other than those coated with photographic film), Exported articles, Second hand articles and recycled materials.
The regulation should be applied 18 months after entry into force. By way of derogations some elements of this regulation shall not apply to Perfluorooctane sulfonic acid and its derivatives (PFOS) which are already covered by the Regulation (EC) No 850/2004.
SEAC proposed a longer transition of 36 months that would have the following merits:
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