PFAS pollution in European waters

Concern about environmental PFAS pollution is increasing

PFAS (per- and polyfluoroalkyl substances) are a large group of chemicals consisting of approximately 10,000 different compounds. Also referred to as ‘forever chemicals’, their extreme persistence in the environment has been understood for a long time. However, other concerning properties of these compounds have become better understood over the past two decades. These properties that are displayed by certain subgroups of PFAS include:

• potential for bioaccumulation in living organisms;
• high mobility in water, soil and air;
• long-range transport potential; and
• (eco)toxicological effects that impact humans and the environment (BAuA et al., 2023). 

Initially, only certain compounds in the group were of primary concern to regulatory authorities, notably PFOS and perfluorooctanoic acid (PFOA). As a consequence, there is much more knowledgeable about the impacts of these compounds, which are now restricted at a global level, than about other members of the PFAS family.

However, there is increasing concern about the harmful effects of all the compounds in the PFAS group, including growing evidence that the less-studied compounds may have similar negative impacts (BAuA et al., 2023). In addition, some PFAS may degrade into so-called arrowhead substances; these are shorter-chain PFAS that are often more mobile and/or bioavailable and hence more problematic than the parent compound.

PFAS pollution in water can harm human health as well as the environment. The EU human biomonitoring project HBM4EU included assessment of PFAS and found that they exceeded safe guideline levels in European teenagers. While accumulation in humans, animals, sediment or soil is mainly due to long-chain PFAS, short-chain PFAS are often found in water and plants as a consequence of their persistence and high mobility (Ghisi et al., 2019; UBA, 2017). In particular, trifluoroacetic acid (TFA), a highly persistent degradation product (i.e. formed from the breakdown of other PFAS including certain pesticides), is on the rise in European groundwater, posing a threat to drinking water since TFA contamination is hard to remove.

Marine currents and sea spray are important pathways for the distribution of PFAS, contributing to their global presence. PFAS have been documented far from their potential sources and across all continents with varying levels of industrialisation. This suggests that long-range transport in the atmosphere is another significant pathway for their distribution (Kurwadkar et al., 2022). They have even accumulated in remote places such as the Arctic.

The Forever Pollution project has estimated that there are around 23,000 PFAS-contaminated sites in Europe; of these, approximately 2,300 are ‘hotspots’ with high levels of pollution that may pose a threat to human health. Another recent study points in the same direction but also acknowledges that a lot is still unknown about the true extent and potential impact of PFAS contamination in surface and groundwater (Ackerman Grunfeld et al., 2024). This issue is also underlined in a recent report by the European Commission's Joint Research Centre which identifies several gaps in our knowledge of PFAS in the aquatic environment; it points to the need for more monitoring data for an effective assessment.

Monitoring PFAS in Europe’s waters

According to the Water Framework Directive (WFD), EU Member States are required to monitor a number of priority substances in surface water. EQS for these substances are then set and used to assess the chemical status of each waterbody. If the annual average concentrations of pollutants are all below the annual average EQS, the specific waterbody is deemed to have a ‘good’ chemical status. Under the WFD, Europe’s water bodies are all required to achieve a good status by 2027, Member States may apply for exemptions to extend the deadline for PFOS and other substances added to the list in 2013, if justified on a limited range of grounds.

PFOS is listed as a priority substance under the WFD and Member States have been required to report on compliance with the EQS since 2021.

In line with Directive 2008/105/EC (as amended by Directive 2013/39/EU), the EQS for PFOS are currently 0.65 nanograms of PFOS per litre (ng PFOS/l) for inland surface waters, 0.13ng PFOS/l for transitional, coastal and territorial waters, and 9.1 micrograms of PFOS per kilogram (μg PFOS/kg) wet weight for biota (fish).

There is currently no comparable EU-level quality standard for PFOS in groundwater. Likewise, no standards have yet been adopted for other PFAS in surface or groundwaters, though EQS for a group of PFAS are currently being established (see Box 1).

A total of 27 European countries have submitted monitoring data to the EEA through the WISE system for the 2010-2022 period. These data have been processed for the purposes of this briefing to provide an overall picture of PFAS contamination in European waters and increase our understanding of the extent to which regulatory thresholds are currently exceeded. Disaggregated data are used for the general statistical analysis (see the methodology section) with a focus on PFOS in water bodies, since there are relatively large amounts of data available on this compound in European waters.

EQS have been established for PFOS in both water and biota, and Member States can choose whether to monitor water, biota or both. However, in the 2010-2022 period, almost all samples analysed were from the water matrix (an average of 98% of the samples), with very few analyses carried out on sediments and biota.

Future EEA briefings may examine other data sets such as PFAS in drinking water, biota and sediments, for which less data are currently available.

PFOS concentrations exceed regulatory threshold levels in many monitoring sites

PFOS water monitoring data from 22 countries for 2018-2022 are given in the interactive map below.

At the EU level, coastal waters exceed the EQS for annual average concentrations of PFOS proportionally more than other bodies of water: 100% exceedances in 2018 (out of six sites), 68% in 2019 (out of 28 sites), 47% in 2020 (out of 75 sites), 86% in 2021 (out of 49 sites) and 73% in 2022 (out of 80 sites). For rivers, the values are stable with around 50-60% of sites (out of a total between 386 and 1,097) exceeding EQS annually over a five-year period. For lakes, exceedances are generally increasing, from 11% in 2018 (out of 28 sites) to 35% in 2022 (out of 150 sites).

At the country level, available data indicate some variability across Europe. In 2022, 14 countries reported monitoring data for PFOS in surface water. In Belgium, France and Iceland, 100% of the reported water bodies exceeded EQS. In the Netherlands, 96% of water bodies exceeded EQS, while in Germany, the figure was 83%. In Italy, 54% of sites exceeded EQS. Five countries reported that less than 20% of sites exceeded EQS: Spain (18%), Ireland (6%), Poland (5%), Croatia (5%) and Estonia (2%). Bulgaria, Latvia and Montenegro had no sites which exceeded the PFOS EQS.

Currently, it is not possible to identify a clear trend as the data set is subject to fluctuations (related to factors such as increased quantity and quality of monitoring over time and the relatively short period of monitoring being evaluated).

As mentioned above, there are currently no EU-wide standards for PFAS in groundwater. The Groundwater Directive (GWD) sets EU-wide quality standards for only a few pollutants and requires Member States:

• to set threshold values for substances of concern at national level;
• to identify upward trends;
• to take measures to prevent or limit the introduction of pollutants into groundwater.

In the context of the voluntary watch list mechanism under the GWD, several Member States monitored a range of PFAS in groundwater from 2017 as part of a pilot study.

Groundwater monitoring data on PFOS were reported to the EEA by six Member States (Czechia, Denmark, France, Ireland, Italy and Slovakia) for the 2018-2022 period. These data are shown in the interactive map above (Figure 1), with different sizes of triangles depending on the concentration found at each monitoring site.

National legislation in certain countries sets specific thresholds for different PFAS; these are useful for assessing the chemical status of water bodies. For example, in Denmark, PFAS reference values for groundwater are set as ‘advisory values’ and they are identical to the Danish drinking water reference values: evaluated as the sum of four specific PFAS (threshold value 0.002mg/l) or the sum of 22 specific PFAS (threshold value 0.1mg/l). In Italy, the threshold value for PFOS in groundwater is 0.03mg/l (or 6.5x10^-4mg/l where there is interaction with surface water) and four other PFAS are regulated. The general trend for the 2018-2022 period indicates a decreasing concentration of PFOS in EU groundwater. However, more data are needed over a longer time period to draw reliable conclusions.

Territorial coverage and number of monitored PFAS

The different monitoring efforts undertaken by each country account for the variability of the results and thus our current understanding of the geographical distribution of contamination. However, the general EU trend indicates that analytical methods for PFOS detection are becoming more sensitive over time. This leads to less uncertainty about the monitoring data, although there are differences from country to country.

Overall, the number of countries undertaking monitoring activities, number of samples taken, number of monitoring sites included and matrices analysed all increased in the 2010-2022 period. This points to better territorial coverage of the data and an increased monitoring effort. France and Italy reported on the highest number of samples.

Most reported samples in 2022 related to rivers (52%) and groundwater (40%), while fewer samples were reported for lakes (5%) and coastal waters (3%).

Monitoring data for a total of 15 different PFAS are included in the data set. PFOS and PFOA are by far the most monitored compounds, but some European countries have started reporting on other PFAS since 2020.

Conclusions

This new evidence provides an overview of PFAS pollution in the environment (with a specific focus on the most monitored substance, PFOS), highlighting the challenges in delivering on the objectives of the zero pollution ambition for a toxic-free environment.

It is hard to draw conclusions on the extent to which regulatory threshold values are exceeded across Europe and the trend over time is not currently clear. This is due to uncertainties in the reported data, data quality and geographical coverage, as well as the increasing number of results. The granularity of the reported data also varies between countries and regions. However, it can be concluded with confidence that a significant number of EU monitoring sites are under pressure due to PFOS pollution.

The results presented in this briefing point to the need for increased monitoring activities using adequately sensitive analytical methods in areas that have poor coverage (i.e. with either very few monitoring activities or where monitoring has only been performed using low sensitivity methods).

PFOS was first regulated around 2010. Despite this, it is still ubiquitous in the environment. Furthermore, a growing understanding of the environmental and human health impacts of PFAS other than PFOS and PFOA underlines the importance of including more PFAS in monitoring programmes. In this context, concerns about the potential risk related to other PFAS which are currently not as well studied as PFOS and which continue to be released into the environment seem well-founded.

This evidence supports the current proposal under the WFD to expand the list of priority substances to include 24 specific PFAS and the need to review the PFAS limits in the DWD. These measures would be in line with the wider regulatory context including the proposal from five national authorities to restrict the entire PFAS group under the Registration, Evaluation, Authorisation and Restriction of Chemicals Regulation, currently being assessed by the European Chemicals Agency (ECHA) and the Commission’s move not to renew the approval of some pesticides. Certain PFAS compounds are already restricted at EU level (or even at international level under the Stockholm Convention): PFOA, PFOS, PFHxS, C9-C14 PFCA and PFHxA.

The objective of the WFD is for all EU water bodies to achieve 'good status' by 2027 at the latest but this target is currently far from being reached, primarily due to a few priority substances such as mercury and brominated flame retardants. Inclusion of recent data on PFAS is likely to make it even more difficult to achieve the policy target since new evidence on the high degree of exceedances for PFOS must now be considered.