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Highly fluorinated substances (PFOS, PFOA and others)

Highly fluorinated substances may be present in impregnated textiles, impregnated paper, detergents and fire-fighting foam. These substances are also contained in products used in workshops and the electronics industry. Highly fluorinated substances are used because they are capable of forming smooth surfaces and repelling water, grease and dirt. They are used in low concentrations in many products.

Areas of use

Textile and leather impregnation

Textile and leather impregnation is one of the most common uses of highly fluorinated substances. Fluorotelomers are used as repellents for dirt and water on the surfaces of textiles, such as tents, shoes, fitted carpets, upholstered furniture and sun blinds.

Water and dirt-repellent textiles may be fabric made of polytetrafluorethylene (Teflon), polyester, polyamide and similar, which is impregnated with a dispersion polymer with 'telomer tails'. Much suggests that it could be that these tails are released from the polymer and that impregnation contains the unbound residues of polymers. The telomers may then slowly degrade into perfluorocarboxylic acids (PFCA).

Paper and food packaging

Paper may be treated with an impregnation product containing derivatives of fluorotelomers (for example, phosphate esters) or fluorotelomer dispersion (polymers with 'telomer tails'). These can be found primarily in food packaging where grease-repellent properties are desirable.

Detergents and cleaning products

Highly fluorinated substances are used in low concentrations in cleaning products such as window cleaning agents, floor polish and other polishes and car care products. Although the concentrations in these products may be low, their release into the environment can be on a considerable scale.

Perfluorooctanoic acid (PFOA) is sometimes called 'the Teflon chemical' by the media. PFOA is indeed used as an additive in the manufacture of the polymer polytetrafluoroethylene (PTFE). Teflon is a trademark. According to the manufacturer, PFOA is no longer included in the finished product, but in the past its manufacture has been a source of release on a large scale into the environment.

Properties

Spread and accumulation in the environment

Highly fluorinated substances form a group of very stable substances. Some of these degrade very slowly or not at all in the natural environment, while others are transformed into persistent substances. Many of these are bioaccumulative; i.e. they accumulate in living organisms. Since highly fluorinated substances repel grease and water, they do not accumulate in fatty tissue the way other bioaccumulative substances do. They bind to proteins and accumulate in other organs in the body, such as the liver, and in the bloodstream.

Perfluorooctane sulfonate (PFOS) and perfluorocarboxylic acids (PFCA) are found in comparatively high concentrations in animals, such as polar bears in the Arctic. These substances have also been found in human blood, including that of newborn babies. There are indications that the longer the highly fluorinated carbon chain is, the higher the toxicity and the greater the potential for bioaccumulation.

PFOS

PFOS (perfluorooctane sulfonate) is a so-called PBT substance, which means that it is persistent, bioaccumulative and toxic. This means that PFOS does not degrade in the natural environment but accumulates there, has a chronic toxic effect, disturbs reproduction and is toxic to marine organisms. 

PFOS has been replaced today by other persistent, highly fluorinated substances which are not bioaccumulative in living organisms to the same extent and are therefore less toxic. The use of substances that can degrade into PFOS has decreased in recent years. However, in our experience they have been replaced for the most part by other highly fluorinated substances. Some of these, such as fluorotelomers, can slowly degrade into PFOA.

PFOA

PFOA (perfluorooctane acid) does not degrade in the natural environment; it disturbs reproduction and is a suspected carcinogen in the human body.

Apart from what we know about PFOA, there is very little information available about the health and environmental effects of perfluorocarboxylic acids. Long-chained PFCAs are persistent and bioaccumulative to a high degree, and therefore several PFCAs with lower carbon chains (C10-C13) are on the EU Candidate List of Substances of Very High Concern. According to Environment Canada, long-chained PFCAs fulfill the criteria for POPs substances according to the Stockholm Convention.