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Per- and Polyfluorinated Chemicals (PFC) - Update
Perfluorinated and polyfluorinated chemicals (PFCs) are a group of substances comprising several thousand individual substances. The best known of these are perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), whose use is now banned or restricted. Chemically, they are carbon chains of different lengths in which the hydrogen atoms are either completely (perfluorinated) or partially (polyfluorinated) replaced by fluorine atoms. According to current knowledge, PFCs are exclusively of anthropogenic origin and do not occur naturally.
Due to their special properties - water-, grease- and dirt-repellent as well as chemically and thermally stable - PFCs are used in many different areas. PFCs are used, among other things, for textile impregnation (e.g. outdoor and work clothing) and paper finishing (e.g. paper cups, baking paper, photo paper).
Despite their exclusively anthropogenic origin, PFCs have already been detected in the most remote areas, such as the Arctic or alpine lakes. In addition to direct input into the environment, PFCs are also distributed over large areas via the air and water bodies due to their persistence and mobility. Long-chain perfluorinated PFCs in particular also accumulate in organisms and the food chain.
The health effects of PFCs have been explored in a variety of animal and epidemiological studies, where PFCs have been linked to developmental toxic effects, reduced fertility, decreased antibody formation, increased cholesterol concentration and type II diabetes mellitus.
PFCs fulfil the criteria for classification as PBT substances (persistent, bioaccumulative, toxic) according to the REACH Regulation. Accordingly, their entry into the environment must be avoided, regardless of their concentration and quantity, as such substances are not degraded or are degraded only very slowly and can thus remain in water, soil and also in the food chain for very long periods of time.
The substance group of PFCs has also come increasingly into focus in the treatment of contaminated sites in recent years. The areas of application "fire extinguishing foams" and "electroplating" are of particular relevance. The lack of assessment standards and the complex and costly remediation place high demands on investigation, remediation and management concepts.
For the assessment of PFC concentrations in groundwater, low threshold values exist for only 7 PFCs and health guidance values for 6 other PFCs. No generally applicable values are available for the assessment of PFCs in soils. Established analytical methods are available for the mutually similar perfluorinated PFCs, such as PFOS and PFOA. Polyfluorinated PFCs, on the other hand, are characterised by a great diversity of substances and analysis is not possible in many cases. Often these are precursors that can be degraded to persistent perfluorinated PFCs, or the substances are subject to the trade secrets of manufacturing companies.
An actual remediation of PFC-contaminated soils and the only method so far to sustainably remove PFCs from the environment is thermal treatment at temperatures above 1,200°C. Long-chain PFCs in the water phase can be removed with activated carbon filters. For short-chain PFCs, on the other hand, this is only possible to a limited extent. Suitable disposal facilities are also currently only available to a limited extent. Due to the mobility of the compounds, landfilling PFCs places high demands on leachate collection and treatment in particular.
Literature:
HLNUG Legacy Seminar 2019, Volker Zeisberger: PFC - The most important in a nutshell
HLNUG-Altlasten-annual 2019, Volker Zeisberger: Polyfluorinated PFC - an underestimated danger?
HLNUG-Altlasten-annual 2018, Volker Zeisberger: PFC - A new group of substances also relevant to contaminated sites
Federal Environment Agency (2009): Per- and Polyfluorinated Chemicals. Avoiding inputs - protecting the environment
Federal Environment Agency: Per- and polyfluorinated chemicals (PFC)
https://www.umweltbundesamt.de/pfc-portal-start
Umweltwirtschaft.com (2019), Martin Boeckh: Dealing with PFCs is proving difficult - Part 2: Dumping, piling up - sitting out?
LAWA (2017): Per- and polyfluorinated chemicals (PFCs). Derivation of de minimis thresholds for groundwater
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