Per- and polyfluoroalkyl compounds

Organic compounds which are fully (per-) or partially (poly-) fluorinated

Use

For the last seventy years, companies have been producing perfluorinated and polyfluorinated alkyl compounds (PFAS) in large quantities to make a wide variety of materials heat, water and grease repellent. In most cases, the focus is on surface treatment, for example of textiles, household goods and building materials, in paper coating and in chemical specialities. However, PFAS are also found in cleaning agents, fire-fighting foams, cable coating, hydraulic fluids and are also used in metallurgy, electronics and medical technology. In this respect, they can get into the environment during production, use and disposal and cause harm to humans.

According to OECD estimates, there are over 4000 PFAS that are partially or fully fluorinated. A basic distinction can be made between polymers and non-polymers. All PFAS are man-made, they do not occur naturally in the environment. Polymers include perfluoropolyethers, polymers with fluorinated side chains and fluoropolymers such as polytetrafluoroethylene (PTFE), which is known in various products under the trade names Teflon®, Scotchgard™ and Goretex®.
Non-polymers consist of both, perfluorinated and polyfluorinated alkyl substances. Perfluorinated compounds can be transformed from polyfluorinated substances, for example by metabolic processes in humans, animals, plants and microorganisms or by non-biological transformation in the environment.

Data from the German environmental specimen bank

PFAS investigations are among the priorities of the German Environmental Specimen Bank. There are a lot of data for perfluorinated as well as for some polyfluorinated alkyl substances from young adults as well as from plants, animals and non-biological samples from inland waters, coasts and terrestrial ecosystems. For most sample types there are not only time series for regulated but also for non-regulated PFAS.

Hazards for humans and the environment

Perfluorinated compounds are very persistent in the environment. Depending on their substance properties they are distributed in the environmental media, some compounds also accumulate in the food web. With the oceans and via the air path they can spread over the earth and thus reach even the remote polar regions. Some of the perfluorinated compounds are known to be toxic. Much less is known about the behavior of polyfluorinated alkyl compounds in humans and the environment. This is a major challenge given the estimated number of over 4,000 PFAS.

The lead components of PFAS, i.e. the most frequently studied and toxicologically evaluated substances, are perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). PFOS has spread worldwide via water and air and is also detectable in all samples of the Environmental Specimen Bank.

Legal regulations

As early as 2001, the largest producer 3M stopped production of PFOS in Europe. Since 2006, the EU authorities have restricted the use of PFOS with a few exceptions. In 2009, PFOS was included in Annex B of the Stockholm Convention, which regulates the restriction of production and use. PFOS is a priority hazardous substance under the Water Framework Directive (EU, 2017; EU, 2000). The EU countries monitor the environmental quality standard of 9.1 ng/g wet weight fish to assess the good chemical status of waters.

The use of PFOA and its precursor compounds is restricted under REACH, the EU is aiming for inclusion in the Stockholm Convention. A number of other PFAS are on the REACH list of substances of very high concern (SVHCs). In June 2019, GenX (a short-chain PFAS substitute for PFOA in fluoropolymer production) became the first chemical to be included in the SVHC list due to its persistent, mobile and toxic properties that pose a threat to drinking water and the environment. Several PFAS are included in the Community rolling action plan (CORAP) to be evaluated in the coming years.

It is becoming increasingly clear that it would become extremely time-consuming and costly to carry out risk assessments for each individual substance. Furthermore, a substance specific approach would also be challenging for environmental monitoring to fully understand exposure, given the more than 4 000 PFAS registered. Therefore, authorities and research are looking for complementary and precautionary approaches to regulating PFAS.

Assessment criteria for human health

In environmental medicine, measured data from human biomonitoring studies are compared with assessment values based on results of toxicological and/or epidemiological studies. In Germany these health-related values are the human biomonitoring values (HBM-I and HBM-II values). The HBM-I value of 2 µg/L for PFOA and 5 µg/L for PFOS indicates the concentration of a substance in the blood plasma below which no adverse health effects are expected. If the HBM-II value is exceeded, being a) larger than 5 µg PFOA/L or 10 µg PFOS/L blood plasma for women of childbearing age of and b) larger than 10 µg PFOA/L or 20 µg PFOS/L blood plasma for the remaining population groups of , a health impairment that is to be regarded as relevant is possible for those affected. Blood plasma concentrations above the HBM-I level but below the HBM-I level indicate an exposure at which, according to current knowledge, effects can no longer be excluded with sufficient certainty. Both HBM-I and HBM-II values are based on an assessment of the population-related risk with regard mainly to developmental toxicity and reduced birth weights, reduced fertility, reduced antibody formation (immune system), increased (LDL and total) cholesterol concentrations and diabetes mellitus type II. When assessing individual risk, other factors such as age, lifestyle, genetic and family predisposition etc. must always be taken into account.

Current investigations

Routine measurements in the ESB program

The routine measurements cover 31 PFAS, namely 17 perfluorinated and 14 polyfluorinated compounds. In addition, the TOP Assay is applied, a new method for recording the total PFAS load, to obtain information on known and also unknown PFAS in the environmental samples.

Fluorbank

The Environmental Research Centre (UfZ) Leipzig together with the Technology Centre (TZW) Karlsruhe is examining environmental samples of the Environmental Specimen Bank for PFAS. In addition to targeted detection methods for more than 70 PFAS, non-target screening methods are also used to search for previously unknown problem PFAS. In the Fluorbank project, summary methods are also used in order to be able to provide an overall assessment of the pollution of the German Environmental Specimen Bank samples with PFAS.

LIFE APEX

In the EU project LIFE APEX (LIFE17 ENV/SK/000355), experts are investigating the exposure of top predators and fish in Europe to chemicals in order to improve chemical management. Both, targeted measurements and non-target screening methods are used. A special focus is on PFAS. For the first time, the experts will develop a systematic overview of the exposure of otters, birds of prey and marine mammals as well as fish, including those from the Environmental Specimen Bank, and propose measures for their protection.

Substances

  • Perfluorobutanoic acid
    Fluorocarbon with 4 C-atoms
  • Perfluoropentanoic acid
    Fluorocarbon with 5 C-atoms
  • Perfluorohexanoic acid
    Fluorocarbon with 6 C-atoms
  • Perfluoroheptanoic acid
    Fluorocarbon with 7 C-atoms
  • Fluorocarbon with 8 C-atoms
  • Perfluorononanoic acid
    Fluorocarbon with 9 C-atoms
  • Perfluorodecanoic acid
    Fluorocarbon with 10 C-atoms
  • Perfluoroundecanoic acid
    Fluorocarbon with 11 C-atoms
  • Perfluorododecanoic acid
    Fluorocarbon with 12 C-atoms
  • Perfluorotridecanoic acid
    Fluorocarbon with 13 C-atoms
  • Perfluorotetradecanoic acid
    Fluorocarbon with 14 C-atoms
  • Perfluorobutanesulfonic acid
    Fluorocarbon with 4 C-atoms and one sulfonic acid group; substitute for PFOS in many applications
  • Perfluorohexanesulfonate
    Fluorocarbon with 6 C-atoms and one sulfonic acid group
  • Perfluoroheptanesulfonic acid
    Fluorocarbon with 7 C-atoms and one sulfonic acid group
  • Fluorocarbon with 8 C-atoms and one sulfonic acid group
  • Perfluorodecanesulfonic acid
    Fluorocarbon with 10 C-atoms and one sulfonic acid group
  • Pentafluoropropanoic acid (PFPrA)
  • Perfluorohexadecanoic acid (PFHxDA)
  • Perfluorooctadecanoic acid (PFODA)
  • Perfluoroctane sulfonamide and derivates
  • Fluorotelomer sulfonic acid
  • Polyfluorinated/mixed halogenated sufonic and phosphonic acids
  • Polyfluorinated substances
  • diPAPs
    Polyfluoroalkyl phosphate diesters
  • PAPs
    Polyfluoroalkyl phosphate esters
  • Cyclic PFAS

Specimen

  • Common mussel species as invasive animal in rivers and lakes with high information level for water pollution
  • Bioindicator in rivers and lakes
  • Fine insoluble mineral or organic particles in the water phase
  • Common brown alga of the coastal areas of the North and Baltic Sea
  • One of the most important edible mussel species common in the North and Baltic Sea
  • As the only viviparous fish in German nearshore waters, it is a bioindicator in nearshore coastal marine ecosystems.
  • Inshore, the herring gull mainly feeds from the sea: upon fish, mussels, and crabs.
  • A major primary producer in semi-natural and anthropogenic affected ecosystems.
  • A major primary producer in semi-natural and anthropogenic affected ecosystems.
  • A deciduous tree typical of ecosystems close to dense conurbations and an indicator for the characterisation of the immission situation during the vegetation period.
  • As the most dominant deciduous tree species in Central Europe, it plays a significant role in most nearly natural and also anthropogenically influenced forest ecosystems up to an altitude of 1100 m.
  • The roe deer is the most common of the larger herbivores (first order-consumer) to be found in the wild in Europe.
  • As an organism living at ground level, it is a major driver of the decomposition of organic material (e.g. plant litter).
  • As an organism living at ground level, it is a major driver of the decomposition of organic material (e.g. plant litter).
  • Soil is livelihood and biosphere for humans, animals, plants and soil organisms. All the substances brought in are transported, transformed and/or accumulated in the soil.
  • Student groups with an even number of female and male students at the age of 20 to 29.

Sampling area

Sampling period

1982 - 2019

Extended information

Links to external information and legislation

Literature