PFAS is the abbreviation of per- and polyfluoroalkyl substances, which is a general term for synthetic chemicals that contain fluorine. Read more about the properties and consequences of PFAS in this article.

What defines PFAS and what types are there?

PFAS is the abbreviation for per- and polyfluoroalkyl substances, which is a general term for synthetic chemicals that contain fluorine with strong carbon compounds. In higher concentrations, PFAS are environmentally and health-damaging for humans, animals, and nature.

PFAS are also called eternal chemicals, as they are difficult to degrade organically. It makes everything from rain coats to pizza trays more durable and resistant, as PFAS-treated surfaces make products resistant to, for example, water, grease, oil and other liquids that would otherwise degrade materials over time through repeated exposure.

Under the PFAS term there are many other related abbreviations for chemicals that contain fluorine, such as:

  • PFOS (perfluorooctane sulfonic acid)
  • PFOA (perfluorooctanoic acid)
  • PFNA (perfluorononanoic acid)
  • PFHxS (perfluorohexanesulfonic acid)
  • PAPS (polyfluoroalkyl phosphate esters)

What is the difference between perfluoroalkyl substances and polyfluoroalkyl substances?

The chemical composition of PFAS is primarily fluorine-containing. The difference between perfluoroalkyl substances and polyfluoroalkyl substances depends on how many atoms of hydrogen in the carbon chain have been replaced by fluorine.

In perfluoroalkyl substances, all hydrogen atoms have been replaced by fluorine, while polyfluoroalkyl substances are characterised by containing fluorine, but still remaining a number of hydrogen atoms in the carbon chain.

PFAS is the abbreviation for per- and polyfluoroalkyl substances - © Hans Buch A/S

Where does PFAS come from?

PFAS are man-made chemicals that contain fluorine and have been used in industry since the 1950’s to create more durable products. With a strong chemical bond to carbon, fluorine-containing substances are difficult to degrade.

PFAS are also called eternal chemicals, which due to their properties are suitable for solving difficult tasks and extending the lifespan of products for many areas of application. This is because PFAS is liquid, oil and grease repellent and can withstand very high temperatures, making the products more durable.

PFAS are found in many consumer goods and materials such as:

  • Plastic and paper food packaging
  • Adhesives
  • Paint, varnish and impregnation
  • Detergents
  • Cosmetics
  • Kitchenware with teflon coating (polytetrafluoroethylene) such as pots, frying pans, baking tins and baking paper

Why is PFAS harmful to health?

In higher concentrations, PFAS are harmful to the health of humans, animals and nature. Exactly how big a health risk PFAS poses is still difficult to conclude indisputably. Through research, however, potential human risks are pointed out, which when exposed to PFAS has a potential effect on the immune system and general human health.

This applies to, among other things, elevated cholesterol, a slight harmful effect on the liver and reduced birth weight, while PFAS is still suspected of a slightly increased risk of certain types of cancer when exposed to higher concentrations of PFAS. High exposure to PFAS is, for example, due to consumption of highly contaminated drinking water and foods, or through the handling and production of PFAS-containing chemicals.

How is PFAS reduced or removed?

In water treatment plants and waste water plants, for example, PFAS can be removed using carbon filters. The strong carbon bond that PFAS has due to fluorine makes it attach the carbon. The carbon with PFAS is then filtered out later in the water purification process. Hans Buch’s customer Split Water Nordic has found a more effective purification of PFAS and pesticides using a special filter with active carbon.

Hans Buch has contributed to Split Water Nordic’s unique and scalable application with technical guidance and supply of components. Among other things, we have supplied pumps and stainless valves, as well as instrumentation in the form of flow and level meters, transmitters and switches, as well as meters for pressure, pH, temperature and turbidity.

Read Hans Buch’s entire customer case: “Effective water treatment with Hans Buch’s wide quality range

What does the legislation say about limit values ​​for PFAS?

The limit values ​​are continuously adjusted for how high a concentration of PFAS may occur in a given environment or element. In Denmark, the limit values ​​are set in, e.g., Drikkevandsbekendtgørelsen (The Drinking Water Executive Order) and in Miljøbeskyttelsesloven § 14 (Section 14 of the Environmental Protection Act).

The limit values ​​constitute the quality criteria for human health to protect against pollution from the chemicals that we are exposed to in everyday life via air, soil, sludge, and groundwater, drinking water and bathing water. In addition, there are quality criteria for the aquatic environment, which with their limit values ​​are determined according to the PFAS effect on animals and plants in and around lakes, streams and the sea.

The limit values ​​are defined on the basis of “4 PFAS”, which covers a total limit value for the occurrence of PFOA, PFOS, PFNA and PFHxS. “22 PFAS” describes the total permitted value from a larger register of identified fluorine-containing substances under the PFAS term.

Examples of limit values ​​for PFAS

  • Soil – milligrams per kilogram of dry matter (mg/kg TS) – last updated in 2019:
    The total sum of “4 PFAS” occurrence of maximum 0.01 mg
    The total sum of “22 PFAS” occurrence of maximum 0.4 mg
  • Groundwater and sludge – micrograms per liter (µg/L) – last updated in 2021:
    The total sum of “4 PFAS” occurrence of maximum 0.002 µg/L
    The total sum of “22 PFAS” occurrence of maximum 0.1 µg/L


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