Paul Nathanail, managing director of specialist environmental consultancy Land Quality Management Ltd discusses a group of contaminants, including PFAS, that are causing worldwide concern
There are a number of chemicals, particularly those known as PFAS, which are of increasing concern when it comes to land contamination, causing environmental issues. So what are they and what are the issues?
#TLDR: Banned fire-fighting agents containing fluorine can threaten human and environmental health; aware buyers know where to look on former military brownfields
Robin Williams described conditions in the jungle of Vietnam as “hot and wet”. When a fire rages however, temperatures are so high that fire-fighters need substances that will withstand the heat and suffocate the fire. Foaming agents have proven to be successful in fighting fires but the very chemistry that makes them effective also makes them potent environmental contaminants: they resist breakdown, they are mobile and are highly toxic to both humans and ecosystems.
The most challenging fire-fighting chemicals are [alkyl] chains of eight carbon atoms with varying numbers of fluorine atoms. They are collectively known as per- poly- fluoroalkyl substances (PFAS for short). Geek point: “per” refers to when all the hydrogens have been replaced by fluorine and the “poly” refers not to parrots but to when some but not all hydrogen atoms have been replaced. Fluoride in toothpaste may be good for your teeth but this highly reactive ion also bonds so tightly with the carbons that PFAS are able to survive at high temperatures, resist chemical and biological degradation. If they are eaten by fish or humans they attach themselves to proteins and accumulate in the body.
What has this got to do with building, planning and building control?
Absolutely nothing… unless you are redeveloping a former airfield or major industrial facility where fire-fighting foams may have been used, to fight real fires or simply to train fire fighters. Detailed information about site layouts can help focus attention on those locations where PFAS may be most likely to be expected. This was identified back in the mid-90s when the Department of the Environment Industry Profiles listed fire-fighting agents, including fluorinated surfactants, among the potential contaminants at for example airports.
Some PFAS substances, notably PFOS and PFOA, were also used as a protective coating for carpets, textiles and leather, in various household and industrial cleaning products, electronics and non-stick cookware. PFOA was used in making proprietary and other forms of non-stick agent. The manufacture and use of PFOS and PFOA have been prohibited across the European Union since a 2006 directive came into force in 2008. PFOA manufacture ceased in 2015.
Today groundwater at sites in for example Australia, the USA and Scandinavia is being investigated and cleaned up to ensure public health is protected. However, the UK seems to be lagging behind. This despite the substantial quantity of PFOS fire-fighting agents used in the UK. During the 2005 Buncefield oil refinery fire, some 500kg of PFOS, about a quarter of the UK stocks, were used to fight the fire. The post-fire clean up involved removing, storing and eventually treating some 50 million litres of liquid – equivalent to 25 Olympic size swimming pools.
As the government seeks to support house building across the country, it is selling off surplus public land for development. The main departments with surplus land are Health and… Defence. Defence sites often had specific areas set aside for fire-fighters to practice, often using real PFAS foaming products. So (land) buyer beware! Make sure the history of that redundant airfield is well understood and the potential for costly remediation of groundwater affected by fire-fighting agents is accounted for when you negotiate your price. And don’t forget, this is not new – government guidance warned about this family of persistent, toxic and mobile contaminants well over twenty years ago.
Some further reading
This is a personal view and guest blog written for Argyll Environmental by Paul Nathanail, managing director of specialist environmental consultancy, Land Quality Management Ltd.