Risk management strategy for perfluorooctane sulfonate and its salts and precursors: chapter 6
There are no existing controls on PFOS, its salts and its precursors in Canada.
The United States Environmental Protection Agency (EPA) has adopted two federal Significant New Use Rules (SNUR) for 88 perfluorooctyl sulfonate substances that apply to new producers and for new uses of these substances. A third SNUR for 183 perfluoroalkyl sulfonate substances has been posted for stakeholder review by August 8, 2006. The 271 substances listed in the three SNURs include perfluorooctane sulfonic acid (PFOSH) and certain of its salts, perfluorooctane sulfonyl fluoride (POSF), certain higher and lower homologues of PFOSH and POSF, polymers that are derived from PFOSH and its homologues, as well as other substances that have the potential to degrade to PFOSH.
The SNURs require manufacturers and importers to notify the EPA at least 90 days before new manufacture or import of these substances. This provides the EPA with the necessary time to evaluate the intended new use and prohibit or limit the new activity if necessary. While the SNURs do not require current manufacturers to stop producing or selling the substances, the only manufacturer in the United States voluntarily discontinued production in 2002. Therefore, once existing stocks are exhausted, the three SNURs will essentially restrict all manufacture and importation.
Four uses are identified as not significant new uses as defined by the SNURs, and as such are exempt from the restrictions on manufacture and importations. These four uses are:
- As an anti-erosion additive in fire-resistant phosphate ester aviation hydraulic fluids;
- As a component of a photoresist substance, including a photo acid generator or surfactant, or as a component of an anti-reflective coating used in a photomicrolithography process to produce semiconductors or similar components of electronic or other miniaturized devices;
- In coatings for surface tension, static discharge, and adhesion control for analog or digital imaging films, papers and printing plates, or as a surfactant in mixtures to process imaging films; and,
- As an intermediate only to produce other chemical substances to be used solely for the uses listed in 1, 2, or 3.
The Organization for Economic Co-operation and Development (OECD) hazard assessment report has concluded that PFOS's persistence, its presence in the environment and in a number of wildlife species, and bioaccumulation potential are a cause for concern. In 2002, a number of OECD countries agreed to contact the PFOS manufacturers in their countries to determine whether these companies had plans to phase out PFOS production. As well, member countries agreed to report every two years on new PFOS-related information concerning production, use and exposure, along with new information on routes of exposure. A survey on the production and use of PFOS, PFAS, perfluorooctanoic acid (PFOA), related substances, products and mixtures containing these substances was circulated to OECD countries in 2004 to support these actions. Ten member countries submitted responses. The results indicated that substances containing solely PFOS and PFOS products and mixtures are still being imported and manufactured by member countries. The majority of the reported PFOS use is in the firefighting (existing AFFF stock), metal plating, photographic, semiconductor and aviation (hydraulic fluids) sectors, Essential uses were reported for existing stocks of AFFF, aircraft hydraulic fluids, surfactants for metal plating and in the photographic and semiconductor sectors. No new uses for PFOS were reported. This survey is being repeated in 2006.
Australia has produced two Alerts concerning PFOS through its National Industrial Chemicals Notification and Assessment Scheme (NICNAS). The first Alert indicated that all 3M water, oil, soil and grease repellent products containing PFOS were to be phased out in Australia by September 2002 and PFOS use for leather products was to be phased out by March 2003. All other PFOS-containing products, including firefighting foams and industrial additives, were to be phased out in Australia by December 2003. The Alert states that the NICNAS will consider regulatory actions regarding PFOS once the OECD concludes its assessment of PFOS. The second Alert, dated April 30th 2003, makes recommendations regarding PFOS, PFAS and PFOA. These recommendations include:
- That PFOS(and PFAS-based chemicals) be used only for essential uses for which there is no suitable alternative, such as certain class B firefighting foams;
- That Class B firefighting foams not be used in fire training exercises; and,
- That caution be used in selecting PFOA as an alternative for PFOS since PFOA may show the same environmental and health concerns as PFOS.
In April 2005, Norway proposed major reductions in emissions of PFOS by 2010.
Sweden proposed the listing of PFOS and its precursors in Annex A of the Stockholm Convention on Persistent Organic Pollutants (POPs) in June 2005. At the November 2005 meeting of the Persistent Organic Pollutants Review Committee, it was decided that the screening criteria of the Convention had been fulfilled for PFOS and that an ad hoc working group under the Convention would be established to review the proposal further and to prepare a draft risk profile.
In October 2005, the UK published a proposed national action plan that would restrict the use and marketing of PFOS and substances that degrade to it.
In December 2005, the Parties to the United Nations Economic Commission for Europe (UNECE) Long-Range Transboundary Air Pollution (LRTAP) Convention's Protocol on POPs agreed that PFOS should be considered as a persistent organic pollutant. The convention will explore management strategies in 2006.
The European Union published a proposed directive relating to restrictions on the marketing and use of PFOS on December 5, 2005. The restrictions relating to PFOS substances include:
- May not be placed on the market or used as a substance or constituent of preparations in a concentration equal or higher than 0.1% by mass;
- May not be placed on the market in products or parts thereof in a concentration equal or higher than 0.1% by mass; and,
- Exemptions to the restrictions include coatings for photolithography processes, photographic coatings applied to films, papers, or printing plates, mist suppressants for chromium plating, hydraulic fluids for aviation, firefighting foams and closed systems releasing less than 1 µg per kg and where the release corresponds to less than 0.1% by mass of the PFOS used in the system.
The Chromium Electroplating, Chromium Anodizing and Reverse Etching Regulations under CEPA 1999 have been proposed to limit emissions of hexavalent chromium from chromium electroplating, chromium anodizing and reverse etching facilities in Canada and are expected to come into force in 2006. One of the three permissible control options under these proposed regulations is a requirement to maintain the surface tension of plating solutions below specified limits through the addition of surfactants combined with daily measurements of surface tension. The majority of the surfactants currently in use in the electroplating sector contain PFOS. Environment Canada recognizes the need for consistency between the requirements of the proposed Chromium Electroplating, Chromium Anodizing and Reverse Etching Regulation and the proposed risk management approach for PFOS. The proposed consultation approach, as outlined in section 9 of this report, will provide the opportunity for continued discussions between Environment Canada and affected stakeholders on these two initiatives.
Alternatives to PFOS, its salts and its precursors are available for the vast majority of industrial and manufacturing applications. The voluntary phase-out of PFOS production in 2002 accelerated the switch to alternative products.
Research is ongoing to identify alternative substances to deal with the remaining applications for photolithography, surfactants for electroplating, photographic coatings and aviation hydraulic fluids where PFOS is still used.
Alternatives that have been chosen in the past include perfluorobutane sulphonate substances, fluorotelomers as well as hydrocarbon-based and silicone-based surfactants. It should be noted that similar environmental concerns have been noted internationally for some fluorotelomer chemistries. In this regard, Regulations Amending the Prohibition of Certain Toxic Substances Regulations 2005 to include four new fluorotelomer-based substances were published on June 17, 2006.
PFOS, its salts and its precursors are expected to be effectively destroyed by high temperature incineration. The carbon-sulphur bond in PFOS, its salts and its precursors is relatively weak and is expected to break down first at elevated temperatures ranging from 760 to 982°C. Other technologies that have been reported to safely destroy PFOS, its salts and its precursors include plasma gasification, microwave plasma and removal of PFOS via carbon adsorption followed by incineration at 1200°C.
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