| Units | Ref. | ||
|---|---|---|---|
| CAS | 1763-23-1 | - | - |
| Molecular formula | C8F17O3S | - | - |
| Molar weight | 500.13 | g mol-1 | - |
| Melting point | 51.9 | °C | [1] |
| Boiling point | 229.28 | °C | [2] |
| log KOW | 4.26 | - | [2] |
| Water solubility | 0.003124 | g m-3 | [2] |
| Vapor pressure | 0.853 | Pa | [2] |
| Henry's law constant | 0.011 | atm m3 mol-1 | [2] |
| log KOA | 6.627 | - | [2] |
| log KOC | 4.855 | - | [2] |
Perfluorinated substances with long carbon chains, including PFOS, are both lipid-repellent and water-repellent. Therefore, the PFOS-related substances are used as surface-active agents in different applications. The extreme persistence of these substances makes them suitable for high temperature applications and for applications in contact with strong acids or bases. It is the very strong carbon-fluorine binding property that causes the persistence of perfluorinated substances. The historical use of PFOS-related substances in the following applications has been confirmed in the US and the EU.
- Fire fighting foams
- Carpets
- Leather/apparel
- Textiles/upholstery
- Paper and packaging
- Coatings and coating additives
- Industrial and household cleaning products
- Pesticides and insecticides In the UK study, detailed information has been received from the following sectors that currently use PFOS-related substances:
- Use of existing fire fighting foam stock
- Photographic industry
- Photolithography and semiconductor
- Hydraulic fluids
- Metal plating
There is to date very limited information regarding the emissions and pathways of PFOS to the environment. The occurrence of PFOS in the environment is a result of anthropogenic manufacturing and use, since PFOS is not a naturally occurring substance. Releases of PFOS and its related substances are likely to occur during their whole life cycle. They can be released at their production, at their assembly into a commercial product, during the distribution and industrial or consumer use as well as from landfills and sewage treatment plants after the use of the products (3M, 2000). Manufacturing processes constitute a major source of PFOS to the local environment. During these processes, volatile PFOS-related substances may be released to the atmosphere. PFOS and PFOSrelated substances could also be released via sewage effluents (3M, 2000). High local emissions are indicated by one study that showed extremely high concentrations of PFOS in wood mice collected in the immediate vicinity to 3M’s fluorochemical plant in Antwerpen, Belgium. High concentrations of PFOS were also found in liver and blood from fish collected in the Mississippi River at the immediate vicinity of another 3M fluorochemical plant at Cottage Grove in Minnesota (MPCA, 2006). Fire training areas have also been revealed to constitute a source of PFOS emissions due to the presence of PFOS in fire-fighting foams. High levels of PFOS have been detected in neighbouring wetlands of such an area in Sweden (Swedish EPA, 2004) as well as in groundwater in the US close to a fire-training area. An investigation on the uses of PFOS and PFOS-related compounds in Norway in 2005 shows that approximately 90% of the total use is in fire extinguishers. Estimated releases of PFOS related to fire extinguishers are at least 57 tonnes since 1980 to 2003 (2002; 13-15 tonnes). Remaining quantities of fire extinguisher foam in Norway are estimated to be a minimum of 1.4 million litres, which corresponds to an amount of approximately 22 tonnes PFOS. Releases from the municipal sector in Norway, 2002, were estimated to be 5-7 tonnes. The use of PFOS in semiconductors is estimated to result in a release of 43 kg per year in the EU, according to the Semiconductur Industry Association (SIA, 2006). This corresponds to 12% of the total PFOS use in this application. PFOS released in the USA from semiconductors is estimated to be in the same range. The releases of sulfonated perfluorochemicals, including PFOS or PFOS-related substances, from different product usages have been estimated (3M Speciality Materials, 2002). For example, garments treated with home-applied products, are expected to lose 73% of the treatment during cleaning over a 2-year life span. A loss of 34% to air is expected from spray can products during use, while up to 12.5% of the original content may be remaining in the cans at the time of disposal. One route for PFOS and PFOS-related substances to the environment may be through sewage treatment plants (STPs) and landfills, where elevated concentrations have been observed compared to background concentrations. Once released from STPs, PFOS will partially adsorb to sediment and organic matter. A substantial amount of PFOS may also end up in agricultural soil, due to the UNEP/POPS/POPRC.2/17/Add.5 14 application of sewage sludge. The primary compartments for PFOS are therefore believed to be water, sediment and soil. Dispersion of PFOS in the environment is thought to occur through transport in surface water, or oceanic currents, transport in air (volatile PFOSrelated substances), adsorption to particles (in water, sediment or air) and through living organisms (3M, 2003a). One major obstacle when trying to estimate the releases of PFOS to the environment is that PFOS can be formed through degradation of PFOS-related substances. The rate and the extent of that formation are presently unknown. In a study on Swedish STPs, higher concentrations of PFOS were found in the effluents compared to incoming sewage water, which could indicate that PFOS was formed from PFOS-related substances.
PFOS is extremely persistent. It has not shown any degradation in tests of hydrolysis, photolysis or biodegradation in any environmental condition tested. The only known condition whereby PFOS is degraded is through high temperature incineration. PFOS is persistent in the environment and has been shown to bioconcentrate in fish. It has been detected in a number of species of wildlife, including marine mammals. Its persistence, presence in the environment and bioaccumulation potential indicate cause for concern. It appears to be of low to moderate toxicity to aquatic organisms but there is evidence of high acute toxicity to honey bees. No information is available on effects on soil- and sediment-dwelling organisms and the equilibrium partitioning method may not be suitable for predicting PNECs for these compartments. PFOS has been detected in sediment downstream of a production site and in effluents and sludge from sewage treatment plants. Environmental toxicity data for PFOS is predominantly found for aquatic organisms such as fish, invertebrates and algae, and for birds.
Sufficient information exists to address hazard classification for all SIDS human health endpoints. PFOS is persistent, bioaccumulative and toxic to mammalian species. There are species differences in the elimination half-life of PFOS; the half-life is 100 days in rats, 200 days in monkeys, and years in humans. The toxicity profile of PFOS is similar among rats and monkeys. Repeated exposure results in hepatotoxicity and mortality; the dose-response curve is very steep for mortality. This occurs in animals of all ages, although the neonate may be more sensitive. In addition, a 2-year bioassay in rats has shown that exposure to PFOS results in hepatocellular adenomas and thyroid follicular cell adenomas; the hepatocellular adenomas do not appear to be related to peroxisome proliferation. Further work to elucidate the species differences in toxicokinetics and in the mode of action of PFOS will increase our ability to predict risk to humans. Epidemiologic studies have shown an association of PFOS exposure and the incidence of bladder cancer; further work is needed to understand this association.
[1] US EPA. [2009]. Estimation Programs Interface Suite™ for Microsoft® Windows, v 4.00]. United States Environmental Protection Agency, Washington, DC, USA
[2] US EPA. [2009]. Estimation Programs Interface Suite™ for Microsoft® Windows, v 4.00]. United States Environmental Protection Agency, Washington, DC, USA
[3] IPCS: Intox Databank, http://www.intox.org/databank/index.htm
[4] ATSDR: Agency for toxic substances and disease registery, http://www.atsdr.cdc.gov/
[5] TOXNET: TOXikology Data NETwork TOXNET - http://toxnet.nlm.nih.gov/
[6] IRZ: Integrovaný registr znečišťování životního prostředí (IRZ) : http://www.irz.cz/
