What is the Difference Between PFOS and PFAS?

Perhaps more commonly referred to as “forever chemicals”, perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a group of synthetic compounds that earned their moniker due to their ability to persist in the environment for a considerable length of time. Totalling some 4,700 manmade chemicals, PFAS are being monitored with some trepidation by the scientific community, which is concerned by their longevity and mobility – and by their potential health implications for the human body.

Perfluorooctane sulfonate (PFOS) is one such “forever chemical”. It is a fluorinated organic compound which was initially developed for industrial purposes in the 1940s, but has since been phased out of production and circulation in most western countries due to fears over the detrimental impacts it may incur at high accumulations. PFOS is just one of thousands of PFAS chemicals, though much more is known about PFOS than almost all other compounds in the family.

Handy but hazardous

PFOS was first deployed over half a century ago as a means of protecting materials and surfaces against water, stains and grease. It was widely used in the manufacture of carpets, textiles and leather, while it was also a popular ingredient in other household items such as cleaning agents, sprays, paints and waxes. Aside from its ubiquity in the domestic sphere, PFOS was also used for a variety of industrial applications, including in the semiconductor and photographic sectors, firefighting foam formula and as a lubrication or hydraulic fluid in the aviation and transportation industries.

However, its ability to withstand millennia in the natural world and bypass wastewater filtration systems without breaking down first raised concerns among scientists in the 1970s. Because it is able to persist for such a long time, it has travelled to almost all parts of the globe and has accumulated in our seas and oceans, in the bodies of the animals which dwell in them and even among the human race, as well.

Taking precautions

With preliminary studies into the potential health ramifications of high PFOS concentrations showing some alarming results, the decision was taken to prohibit the production, sale and use of PFOS in the UK, the EU and the US in the late 1990s and early 2000s. Despite those rulings, PFOS is still commonly used in many developing countries, whose products can be exported to the western world. As a result, PFOS is capable of contaminating water supplies even in those countries in which its use is banned.

For that reason, it’s imperative that adequate precautions are taken to ensure that the drinking water which serves the British populace does not contain high levels of the substance. The technology involved in such testing is complex and sophisticated, involving the use of advanced analytical methods to arrive at a judgement. The article Screening technique for Adsorbable Organic Fluoride (AOF) concentrations with the Xprep C-IC is an excellent resource into this area of study for those wish to learn more about it.