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PFOS In Drinking Water

Trace levels of a chemical known as PFOS have been detected in local drinking water, as a result of historic use of fire-flighting foam at Guernsey Airport. The concentrations present are being monitored and managed, to ensure public water supplies remain safe to drink, while long-term steps are taken to remove the source of the chemical.

An independent expert review has concluded appropriate action has been taken to protect public health.  This review was carried out by experts from the UK's Health Protection Agency, now part of Public Health England. 

More information is available in the Frequently Asked Questions below.  The full report, and a non-technical summary, can also be downloaded from this link

Should we be drinking bottled water or boiling the tap water?

There is no need to buy bottled water as the tap water is treated and regularly tested to ensure its compliance with the highest UK drinking water standards. It is safe to drink.

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What is PFOS?

Perfluorooctane sulphonate (PFOS) is one of group of chemicals known as perfluorocarbons (PFCs). It was first used in the 1960s, as a protective coating for materials such as paper, carpets, textiles and leather, and also as an ingredient in various household and industrial cleaning products, some fire fighting foams, and hydraulic fluids used in the aviation industry.

It is now classified as a persistent organic pollutant, which basically means once it gets into the environment it does not easily break down. Small amounts have been found in practically every biological system on the planet.

It is one of more than 130 chemicals which Guernsey Water currently routinely tests for to ensure that local drinking water meets the most rigorous quality standards.

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How long has monitoring been taking place?

A major fire at an oil storage depot at Buncefield in the UK in December 2005 alerted the water industry to the potential contamination of ground water sources by the use of fire fighting foam. Guernsey Water began testing for PFOS in March 2007,and the UK Drinking Water Inspectorate issued guidelines in June 2007, which have been applied locally to ensure the water supply is safe to drink.

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What about those with young children, pregnant mothers or the physically vulnerable?

The concentrations stipulated by the Drinking Water Inspectorate take account of the most vulnerable. It is safe for them to drink water.

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How did this chemical get into the water supply?

The main source of PFOS was identified as Guernsey Airport, where fire fighting foam containing PFOS was historically used either on real incidents or in practice applications. Despite the clear up operation some foam inevitably soaked into the soil, and has gradually been released into the ground water.

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What are the findings of the HPA report regarding human health?

The report's conclusion is that exposure to the trace levels of PFOS that have been detected in local drinking water would not be expected to result in ill health. As health professionals we are always cautious to rule out altogether any risk from exposure to any chemical in the environment, however given all the evidence available we would regard there to be minimal risk.

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What has been done to address the pollution source?

Contaminated ground has been removed from around the airfield, and is now stored in a new sealed containment bund that prevents the chemical being washed out. This is secure while a longer term solution is investigated. Soil containing PFOS has also been identified in a field near Forest Road, which was the site of a fatal plane crash in 1999, and this will be removed soon and stored in the same location.

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What if I have a private well or borehole?

Anyone living in the vicinity of the airport, or the aeroplane crash site on Forest Road, who has a well or borehole can contact Environmental Health and have these tested. All known private supplies in these areas have already been tested, and are continuing to be monitored.

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Why not just treat water at the reservoir?

The most practical option is to prevent pollution from entering the water supply in the first place, rather than having to treat a much larger volume. Pollution is better controlled at source and the law requires such action.

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Does the Airport or Town Fire Brigade still use this foam?

No.

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What advice is given regarding fish at the reservoir?

Members of the Guernsey Trout Society, who are permitted to fish at St Saviour's Reservoir, have been advised to limit their consumption of trout from the reservoir to the equivalent of one whole fish a fortnight. It is very unlikely any anglers are taking enough to cause concern. This advice is purely precautionary, and relates specifically to fish from St Saviour's Reservoir, not any other locally caught or shop-bought fish.

Anglers are also advised not to eat carp from the reservoir, but this is thought to be very unusual.

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What about Alderney?

The Alderney Airport Fire Brigade previously stocked PFOS foam, which has now been replaced. Routine fire training operations have led to some localised ground contamination in some other areas. However trace levels of PFOS entering the water supply are being naturally diluted from other sources, and we do not expect this will require the same approach to remediation as in Guernsey.

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