Highly fluorinated substances are used for creating smooth surfaces resistant to water, grease and dirt. These are used in products such as textiles, repellents, floor wax and ski wax. There are hundreds of different perfluorinated substances. The substances are among those which are the least biodegradable in the natural environment. Studies show that the levels of these substances are increasing in seals, reindeer and polar bears in the Arctic. They have also been found in low levels in human blood. It is primarily in the form of food such as fish and, in certain cases, drinking water that highly fluorinated substances enter the body. PFOS and PFOA are the most common.
At present there are no legally binding limit values of highly fluorinated substances in drinking water, but the National Food Agency, Sweden, has introduced action levels so that the drinking water suppliers and supervisory authorities which inspect the concentrations are able to determine if these pose any risk to health. There are EU limit values for other foodstuffs, known as tolerable daily intake (TDI), which apply to PFOS and PFOA.
Since 2008 the use of PFOS and substances which can be broken down into PFOS has been banned in the EU in the case of most chemical products and articles.