Survey of the Prevalence of
Perfluorooctane Sulphonate (PFOS), Perfluorooctanoic acid (PFOA) and
Related Compounds in Drinking Water and their Sources
The general objectives of this project were (a) to review and assess
any monitoring data currently undertaken regarding PFOS, PFOA and
related compounds in drinking water and its sources in England and
Wales, (b) to develop an accurate and scientifically sound analytical
method for the analysis of these compounds, (c) to devise and perform a
one-year monitoring study of these compounds at 20 sites across England
and Wales, and (d) to identify future research needs.
Perfluorinated chemicals such as PFOS (perfluorooctane sulphonate) and
PFOA (perfluorooctanoic acid) have been used in a number of different
types of products, including performance chemicals such as:
photographic film; surfactant in fire fighting foams; surfactant for
alkaline cleaners; emulsifiers in floor polish; mist suppressant for
metal plating baths; surfactant for etching acids for circuit boards;
pesticides; active ingredient for ant bait traps; and dirt repellent
treatments for textiles (e.g. carpets, home furnishing and leather) and
paper (e.g. food containers and masking papers). PFOS has been shown to
be toxic, persistent and bioaccumulative in the environment. Although
already a focus for restriction within the European Union, its profile
as a potential micropollutant in water was raised following the
Buncefield Oil Depot fire in December 2005 when fire-fighting foam
containing PFOS was used.
- The review of monitoring data in the UK indicated that no
monitoring data were available for PFOA and PFOSA
(perfluorooctanesulphonic acid), and only minimal information was
available for PFOS, which indicates that it is not generally considered
a likely contaminant of UK raw water sources, unless a specific
incident has occurred. Little information was available on the
treatment options for PFOS removal from raw drinking water sources, and
anomalies in the various analytical methods used have been noted.
- The survey of levels of PFOS and PFOA indicated that PFOS
does not appear to be a widespread background contaminant of raw and
treated drinking water in England. When detected, PFOS concentrations
were below the current DWI drinking water guidance levels for England
and Wales. Where PFOS was detected at very low concentrations, the
water source was considered at higher risk due to a specific incident,
or the presence of a local source of contamination (e.g. an airfield).
- Conclusions regarding PFOA are not so clear. However, it
does not appear to be a background contaminant of raw and treated
drinking water in England.
- Where PFOS and PFOA were detected, source water originated
primarily from unconfined aquifers as might be expected if resulting
from point source contamination events.
- From the limited data, no apparent trends in PFOS or PFOA
concentrations in drinking water exist in relation to the type of
treatment, the type of perceived risk in the area, the method of
chlorination, or the season.
- Where PFOS and PFOA were detected, the water treatment
processes involved did not show any obvious signs of being able to
remove PFOS or PFOA. However, it is acknowledged that the Granular
Activated Carbon (GAC) present at two of the affected sites is
relatively old, and separate studies have suggested that new (or
recently regenerated GAC) may be effective in the removal of
- There is no correlation between the presence of PFOS and
PFOA in raw or treated drinking water.
- To further review the monitoring of PFOS, PFOA and PFOSA
being undertaken by the Water Companies and other National Bodies.
- To maintain transparent communication and sharing of
information between all interested parties to further the knowledge
base on perfluorochemicals.
- To further investigate the removal of PFOS and other
perfluorinated compounds during water treatment processes.
- To monitor the use, toxicology and occurrence of other
perfluorinated compounds, which may become compounds of concern in the
Copies of this report may be available as an Acrobat pdf download under the 'Post 2000 Reports' heading on the DWI website.