Risk management strategy for perfluorooctane sulfonate and its salts and precursors: chapter 2
PFOS, its salts and its precursors all belong to the larger class of fluorochemicals referred to as perfluorinated alkyl (PFA) compounds which contain carbons that are completely saturated by fluorine. It is the strength of the carbon-fluorine bonds that contributes to the extreme stability and unique properties of these perfluorochemicals.
For the purpose of this document, the expression "PFOS and its salts" refers to the group of compounds consisting of the PFOS anion, the PFOS acid (PFOSH) and the PFOS salts (PFOS potassium salt, PFOS ammonium salt, PFOS lithium salt and PFOS diethanol-amine salt). While PFOS can exist in anionic, acid and salt forms, the PFOS anion is the most common form in the environment. The PFOS anion has the molecular formula C8F17SO3- and has the structural formula CF3(CF2)7SO3- as shown in Figure 1.
The expression "PFOS precursors" refers to compounds that contain the C8F17SO2, C8F17SO3 or C8F17SO2N group. These compounds were included in the ecological and human health screening assessments and in this Risk Management Strategy since these substances have similar use applications, have the potential to transform or degrade to PFOS in the environment and the final degradation product of these substances is PFOS.
Appendix 1 lists the compounds considered to be PFOS, its salts and PFOS precursors in the final ecological screening assessment report. This list is not considered to be exhaustive and does not preclude PFOS precursors not appearing on this list.
2.2 Production, Import and Use of PFOS, its Salts and its Precursors
PFOS, its salts and its precursors are not manufactured in nor exported from Canada but rather are imported as raw chemicals, products and formulations and in manufactured articles.
Approximately 600 tonnes of perfluorinated alkyl compounds were imported into Canada during 1997-2000, with PFOS and its precursors accounting for 43% of imported perfluorinated alkyl compounds. The primary uses of these substances were applications involving water, oil, soil and grease repellents for fabric, leather, packaging and rugs and carpets; as well as additives in firefighting foams, aviation hydraulic fluids, photographic photofinishing, paints and coatings. The primary supplier of PFOS, its salts and its precursors voluntarily phased out the production of these substances in 2002.
Background information collected in support of this Risk Management Strategy indicates that, since 2002, imports of PFOS, its salts and its precursors into Canada have essentially ceased. This was confirmed by a use pattern survey published on January 15, 2005 under the authority of CEPA 1999. The survey targeted manufacturers, exporters and importers of PFOS in amounts exceeding 100 kg in concentrations of greater than 10 grams per kilogram for the 2004 calendar year. The results indicate that approximately 3 tonnes of PFOS were imported in 2004 for use as a surfactant in the electroplating sector. The survey also reaffirmed that are no manufacturers or exporters of PFOS in Canada. With the exception of an estimated 300 tonne stockpile (representing approximately 3 tonnes of PFOS) of Aqueous Film Forming Foam (AFFF) used for firefighting that was purchased prior to 2002, it is believed that most supplies of PFOS in all other sectors have been depleted.
Despite the voluntary phase-out of PFOS production and the current low level of PFOS imports, the potential does exist for PFOS and PFOS containing products and articles to be imported into Canada in greater quantities in the future as some PFOS production has been identified in other countries.
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