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
Perfluorooctanoic acid 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
Perfluorooctanesulfonic acid 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

Zebra mussel Common mussel species as invasive animal in rivers and lakes with high information level for water pollution
Bream Bioindicator in rivers and lakes
Suspended particulate matter Fine insoluble mineral or organic particles in the water phase
Common bladder wrack Common brown alga of the coastal areas of the North and Baltic Sea
Blue mussel One of the most important edible mussel species common in the North and Baltic Sea
Eelpout As the only viviparous fish in German nearshore waters, it is a bioindicator in nearshore coastal marine ecosystems.
Herring gull Inshore, the herring gull mainly feeds from the sea: upon fish, mussels, and crabs.
Common spruce A major primary producer in semi-natural and anthropogenic affected ecosystems.
Pine A major primary producer in semi-natural and anthropogenic affected ecosystems.
Lombardy poplar A deciduous tree typical of ecosystems close to dense conurbations and an indicator for the characterisation of the immission situation during the vegetation period.
Beech 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.
Roe deer, one-year-old The roe deer is the most common of the larger herbivores (first order-consumer) to be found in the wild in Europe.
Earthworm (Aporrectodea longa) As an organism living at ground level, it is a major driver of the decomposition of organic material (e.g. plant litter).
Earthworm (Lumbricus terrestris) As an organism living at ground level, it is a major driver of the decomposition of organic material (e.g. plant litter).
Soil 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.
Students Student groups with an even number of female and male students at the age of 20 to 29.

Sampling area

BR/NP Berchtesgaden The only high mountains national park in Germany and an area of the Limestone Alps with international relevance
Saarländischer Verdichtungsraum Important, old-industrialised conurbation in Germany.
Bornhöveder Seengebiet Main water divide between the North- and Baltic Sea
Rhein Longest river in Germany
NP Bayerischer Wald Germany's first national park
NP Vorpommersche Boddenlandschaft National Park in the largest brackish water (Bodden) habitat of the world.
BR/NP Wattenmeere National park in the world largest connected sand and mud flats.
Elbe Fourth largest river basin in Central Europe
Verdichtungsraum Halle-Leipzig Region in the chemical triangle of Central Germany
NP Harz Germany's largest forest national park
Solling Second highest and largest low mountain range in Northern Germany
BR Pfälzerwald Germany's largest connected forest area in a range of low mountains
Oberbayerisches Tertiärhügelland The Upper Bavarian Tertiary Uplands are a part of the Southern German Molasse Basin
Donau Second largest river in Europe
Sampling sites (humans) 4 university cities as sampling areas.

Sampling period

1982 - 2019

Extended information

Links to external information and legislation

Literature