PFAS in water environments: recent progress and challenges in monitoring, toxicity, treatment technologies, and post-treatment toxicity

Abstract

There is growing awareness of the environmental presence of per- and polyfluoroalkyl substances (PFAS) and their harmful effects on animals and humans. Recent studies have revealed changes in human embryonic stem cells and maternal biomarkers, underscoring the severity and unpredictable outcomes associated with long-term exposure to PFAS. Monitoring efforts continually identify additional PFAS compounds worldwide, but a standardized and unified approach is still lacking. Traditional treatment methods such as adsorption and membrane filtration have been effective in removing 80-95% of PFAS from wastewater. However, complete removal of short-chain PFAS remains limited to a few recently developed techniques. The inability of advanced treatment methods to eliminate emerging short-chain and ultrashort-chain PFAS suggests the need for more integrated approaches that target all PFAS classes. Additionally, a few studies have discussed the potential toxicity outcomes of these treatments at both laboratory and full-scale levels. While advanced oxidative processes (AOPs) are rapidly gaining attention for degrading 90-100% of PFAS in sewage, it remains challenging to fully break down PFAS into non-toxic, mineralized products such as CO₂ and H₂O due to the strong C-F bonds and the potential toxicity of by-products in post-treated wastewater. Standardized and reliable bioassays for assessing PFAS toxicity are still under development, and current predictive models linking molecular structure to human health effects are at an early stage. This review examines the emerging health and ecological risks associated with both legacy and novel PFAS, alongside recent advances and limitations in individual and combined treatment technologies for water and wastewater. Emphasis is placed on the potential toxicity of degradation products, highlighting the need for more integrated and comprehensive toxicity assessments to guide safer PFAS remediation strategies.

Supplementary information: The online version contains supplementary material available at 10.1186/s40068-025-00411-9.

Keywords: Monitoring; PFAS; Review; Toxicity; Treatment technologies.

Fig. 1

Analysis of the global distributions of total concentrations of 20 PFAS (subject to EU regulation, 20 PFAS in Table S1) on six continents (North America, South America, Europe, Asia, Australia, and Africa). Most of these PFAS were PFCA and PFSA linear chains ranging from C4 to C13: a The percentage of PFAS concentration on each continent was calculated based on a recent analysis of 45,000 samples from different drinking and groundwater locations. b The actual concentration of PFAS in each country

Fig. 2

Some potential sources of PFAS in the aqueous environment. a PFAS can enter the environment through multiple pathways. b Representative information from a previous study showing the PFOS and PFOA emission sources in a major industrial country like China, calculated based on the average occurrence of PFOS and PFOA in each source

Fig. 3

Toxicological effects of PFAS on humans and the main classes involved in triggering their response

Fig. 4

The research progress on PFAS use and treatment. a A timeline of the research progress from the early 1940s until 2023. b Common PFAS treatment technologies in wastewater used since 1981 (the values were calculated based on the estimated number of total studies performed on representative treatment technologies described in the review)

Fig. 5

Degradation processes in combination with high-pressure membrane technologies. 1) Membrane filtration was used with (2 adsorption (Sim et al. 2024); with 3) Oxidative degradation (Fennell et al. 2024); with 4) Direct flow filtration or with 5) Coagulation used as an additional filtration step after 2) (Prajapati et al. 2025)

Fig. 6

Number of papers used in combined treatment techniques since 1981 and until 2023 (calculated based on the treatment approaches described in the manuscript). Activated carbon or membrane processes combined with either AOPs, direct photolysis, or sonication were among the physicochemical treatments found using the Google Scholar search engine. The search engine identified several popular biochemical treatment methods, including bacterial or phytoremediation treatment in conjunction with AOPs. The search for biophysical treatment involved combining physical treatments like membrane processes or activated carbon with bacterial treatment or phytoremediation

Fig. 7

Five common advanced oxidation processes designed and employed to target PFAS. 1) Ozonation assisted by H₂O₂, 2) Fenton process assisted by electrochemical or photocatalytic process, 3) Electrochemical-based reactions, 4) Persulfate (PMS) oxidation, and 5) Tribo- or mechanochemical reaction

Fig. 8

The treatment processes of PFOS and PFOA in China WWTPs and the toxic DPs formed. a Processes and common toxic DPs found in their plant. b The toxicity assessment is used to evaluate their toxic effects on humans. To estimate the risk level of each PFAS, values resulting from quantitative structure–activity relationship (QSAR) modeling were used to calculate the Toxicological Priority Index (ToxPi) score (Liu et al. 2024)