PFAS: forever chemicals—persistent, bioaccumulative and mobile. Reviewing the status and the need for their phase out and remediation of contaminated sites

Abstract

Background Per- and polyfluorinated alkyl substances (PFAS) have received increasing scientific and political attention in recent years. Several thousand commercially produced compounds are used in numerous products and technical processes. Due to their extreme persistence in the environment, humans and all other life forms are, therefore, increasingly exposed to these substances. In the following review, PFAS will be examined comprehensively. Results The best studied PFAS are carboxylic and sulfonic acids with chain lengths of C4 to C14, particularly perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). These substances are harmful to aquatic fauna, insects, and amphibians at concentrations of a few µg/L or less, accumulate in organisms, and biomagnify in food webs. Humans, as the final link in numerous food chains, are subjected to PFAS uptake primarily through food and drinking water. Several PFAS have multiple toxic effects, particularly affecting liver, kidney, thyroid, and the immune system. The latter effect is the basis for the establishment of a tolerable weekly dose of only 4.4 ng/kg body weight for the sum of the four representatives PFOA, PFOS, perfluorononanoic acid (PFNA) and perfluorohexane sulfonic acid (PFHxS) by the European Food Safety Authority (EFSA) in 2020. Exposure estimates and human biomonitoring show that this value is frequently reached, and in many cases exceeded. PFAS are a major challenge for analysis, especially of products and waste: single-substance analyses capture only a fragment of the large, diverse family of PFAS. As a consequence, sum parameters have gained increasing importance. The high mobility of per and polyfluorinated carboxylic and sulfonic acids makes soil and groundwater pollution at contaminated sites a problem. In general, short-chain PFAS are more mobile than long-chain ones. Processes for soil and groundwater purification and drinking water treatment are often ineffective and expensive. Recycling of PFAS-containing products such as paper and food packaging leads to carryover of the contaminants. Incineration requires high temperatures to completely destroy PFAS. After PFOA, PFOS and a few other perfluorinated carboxylic and sulfonic acids were regulated internationally, many manufacturers and users switched to other PFAS: short-chain representatives, per- and polyfluorinated oxo carboxylic acids, telomeric alcohols and acids. Analytical studies show an increase in environmental concentrations of these chemicals. Ultra-short PFAS (chain length C1–C3) have not been well studied. Among others, trifluoroacetic acid (TFA) is present globally in rapidly increasing concentrations. Conclusions The substitution of individual PFAS recognized as hazardous by other possibly equally hazardous PFAS with virtually unknown chronic toxicity can, therefore, not be a solution. The only answer is a switch to fluorine-free alternatives for all applications in which PFAS are not essential.

Managing ubiquitous ‘forever chemicals’: More‐than‐human possibilities for the problem of PFAS

“…Remediation provides a 'solution' to contamination by treating land (or water) to remove toxins. In Aotearoa NZ, remediation of PFAS is both publicly and privately funded; remediation of PFAS overseas has proven to be expensive and often ineffective (Brunn et al, 2023). Efforts to remediate contaminated land focus on historic landfills and mining sites (Ministry for the Environment, 2022b).…”

Application of Ion Mobility Spectrometry and the Derived Collision Cross Section in the Analysis of Environmental Organic Micropollutants

“…PFAS are a large group of synthetic chemicals containing a chain of linked carbon and fluorine atoms, which are widely used in consumer and industrial products. , Due to the high stability of the C–F bond, PFAS do not degrade easily in the environment, which leads to their environmental persistence and high bioaccumulation potential . Currently, more than 14 000 unique PFAS are listed in the CompTox Chemicals Dashboard of the United States Environmental Protection Agency (EPA), and this number is constantly increasing with the advancement of detection technologies and data processing methods.…”

“…Numerous studies showed that exposure to PFAS can lead to adverse health effects at the level of μg/L or less; , therefore, sensitive chemical analytical methods for PFAS are needed to support their further environmental fate and toxicity effect studies. The incorporation of IMS into a LC–MS/MS system can increase the S/N ratios of analytes by removing the background interferences; thus, lower limits of detection (LODs) can be obtained for the analytes. , Gonzalez de Vega et al utilized UPLC–TWIMS–QTOF to quantify the PFAS in Cooks River water and achieved LODs and limits of quantification (LOQs) of 0.19–0.76 μg/L and 0.56–2.30 μg/L, respectively.…”

Photocatalytic and photoelectrocatalytic degradation of perfluorooctanoic acid by immobilised ZnO nanoparticles using electrophoretic deposition

“…5 Notably, PFAS at concentrations of a few μg L −1 or less accumulate in organisms, and are harmful to insects, aquatic fauna, and amphibians. 6 Photocatalysis is considered an efficient method widely used for the decomposition of various pollutants. 7 TiO 2 is the most frequently used photocatalyst, but it has shown insignificant activity for PFOA degradation, whereas In 2 O 3 and Ga 2 O 3 have yielded higher efficiencies.…”