Expert-reviewed journalism: Collaborating with scientists on data collection methodology

The “Map of Forever Pollution” was built by Le Monde and its sixteen media partners for the “Forever Pollution Project” cross-border investigation. It shows for the first time the extent of environmental contamination with PFAS chemicals in Europe.

Short summary

The map highlights four types of sites:

20 PFAS producers: chemical company facilities that manufacture PFAS.

22,934 sites where PFAS contamination is known: sites where PFAS were detected in water, soil or living organisms samples at levels equal to or greater than 10 nanograms per litre (ng/L).

231 Known PFAS users: Industrial sites for which there is evidence of PFAS use, but no testing data, and which can be considered likely to be contamination sources. 

21,426 presumptive contamination sites: sites where testing has not confirmed the presence of PFAS, but which can be presumed to be contaminated on the basis of scientific investigations and expert advice, such as military bases or paper mills. 

In total, about 2,300 sites in Europe can be considered as “hotspots”, i.e. locations where PFAS concentrations reach a level that experts consider hazardous to health (100 ng/L).

Descriptive summary of the research methodology

It took the sixteen media partners in the “Forever Pollution Project” months of painstaking work to build, for the first time in Europe, the map of pollution by “forever chemicals”. Our map reveals the extent of contamination by PFAS (per- and polyfluoroalkyl substances), a family of harmful, persistent man-made chemicals that do not degrade in the environment and will remain with humanity for hundreds, if not thousands of years.

By Stéphane Horel (Le Monde) and the Forever Pollution project, 23rd of February 2023

In order to work with rigour, we have adapted the methodologies developed by renowned scientists and experts. They guided us, sometimes step by step, to carry out this journalistic investigation of an unprecedented nature, which combines science, cartography, history, economics and politics. At the end of this “expert-reviewed journalism” experience, our own methodology will soon be published in the form of an article in a scientific journal.

Our map brings together two types of data on known and on presumptive PFAS contamination of the European territory. First, the locations where sampling by scientists or authorities has detected PFAS concentrations in water, soil or living organisms – known contamination sites. Second, sites where activities have most likely used PFAS – presumptive contamination sites.

Thousands of contaminated sites

In order to draw up an inventory of known contamination, we have collected a hundred databases containing environmental sampling data from twenty-three European countries, gathered by teams of researchers or by public authorities. This unprecedented compilation work has made it possible to locate at least 22,934 contaminated sites where PFAS levels exceed 10 nanograms per litre (ng/L). These sites include 2,300 hotspots” where concentrations exceed 100 ng/l, a level that the majority of experts we have consulted consider to be hazardous to health.

In Scotland and France, we had to wrest sampling data from the authorities using freedom of information requests. The European Commission refused to provide us with data from a pilot study on PFAS in groundwater in eleven countries, on the grounds that it “contracted out the collection and analysis of data” to a consultancy. PFAS were detected in all countries, at sometimes very high levels, the published redacted report shows. 

Twenty producing facilities 

Since sampling efforts differ greatly from region to region, the 22,934 locations on our map probably only give a very underestimated picture of the extent of actual contamination in Europe. 

Our first effort consisted in locating PFAS production facilities. In the absence of an official list, we searched the directories of lobbying organisations in the sector, the companies’ annual reports, product portfolios, and product safety data sheets. The Swiss group Archroma, for example, does not hide the fact that it synthesises PFAS. But where exactly, since it has several factories in Europe? 

In order to locate sites, we spent entire weeks absorbed in the mapping tool Google Maps, scanning landscapes by satellite view, zooming in on the pallid patches of industrial zones, wandering from riverbanks taken over by tangle of steaming pipes to forests pierced by discoloured, lifeless crusts. We travelled in 3D across this ugly Europe of chemical parks, sometimes so vast that they are served by several bus stops, like the one in Burghausen, Germany, which covers an area equivalent to more than 280 football fields.

At the end of our virtual journey, we have identified and located twenty PFAS producers in Europe.

Nearly 21,500 presumptive contamination sites 

Our investigation revealed an even more impressive figure. We have located nearly 21,500 presumptive contaminated sites across Europe. “Presumptive” because their industrial activities, whether past or present, were documented as both users and emitters of PFAS. The criteria to define these presumptive contamination sites were developed by a team of researchers from the PFAS Project Lab (Boston) and their colleagues from the PFAS Sites and Community Resources Map in a methodology designed to map pollution in the United States.

“Our main goal was to address the disconnection between known contamination and where contamination actually is out in the world,” explain Alissa Cordner (Whitman College, Walla Walla) and Phil Brown (Northeastern University, Boston), who coordinated this work. Using the best available scientific data, the team identified three types of activities that are well documented as contamination sources: firefighting foam storage and release sites, waste treatment sites and certain industrial activities.

The purpose is not to “name and shame” and stigmatise particular companies or actors. “Our model,” they continue, “does not  say that every single presumptive contamination site is definitely contaminated with PFAS. ”But it “lets decision makers target and identify sites that might very likely be contaminated.”  Their interactive map of the United States, available online, served as a model for our map of Europe, and shows 1,750 sites of “known contamination” and over 57,400 sites of “presumptive contamination”.

The difficulty of locating presumptive contamination

The main obstacle to the building of a European map is the absence of databases gathering the geolocation coordinates of economic activities in the EU. For example, in the first category of firefighting foam presumptive contaminated sites, 978 large and medium-sized commercial airports, both active and inactive, have been located thanks to an aviation enthusiasts’ website.

As the defence authorities were reluctant to cooperate, we had to identify 642 military bases one by one from multiple open sources. In Flanders (Belgium) and Sweden, the authorities have listed all the incidents related to the use of these foams, which added no less than 11,000 sites on our map. In addition, there are about 1,000 fire-fighting training centres in these countries and in Norway. Missing from our map are the 50,000 municipal fire stations across Europe.

Second category: 4,769 waste disposal and treatment sites and wastewater treatment plants with the highest throughput were all located through several datasets made available by the European Environment Agency (EEA).

The third category proved to be a real headache. In the United States, researchers compiled a list of thirty-eight “presumptively contaminating” industrial activities. While we were able to easily find matches between the American and European systems of nomenclature of economic activities, locating them required considerable effort to get to only a partial result, as the European Union does not have geolocation data for companies.

“Necessary and scary result”

By cross-referencing the resulting list with the non-exhaustive list of the EEA’s European Pollutant Release and Transfer Register (E-PRTR), we finally managed to locate nearly 3,000 industrial facilities. The largest of these are about 1,000 paper mills, which alone release between 31 and 76 tonnes of PFAS into the environment every day, according to the European Commission. This is followed by metal manufacturing and processing (812 sites), manufacture of plastics in primary forms (221), manufacture of refined petroleum products (213), finishing of textile (126) and chemical and leather processing plants. In addition, we have identified around 240 factories of PFAS users, serendipitous findings for the most part. 

“It’s a necessary and also a scary result that you’ve achieved here,” said Phil Brown, stunned at the sight of our dot-ridden Europe. “Something similar has been missing for Europe,” said Martin Scheringer, an expert in environmental chemistry at the Swiss Federal Institute of Technology (Zürich, Switzerland). “Your contribution is therefore extremely important and valuable.”

As impressive as our figures are, they are likely to be greatly underestimated. Our map is nonetheless an unprecedented, perfectible resource, available to all. 

Our primary goal is to inform the public and to provide data to impacted community members, researchers and regulators, and to contribute to building knowledge on PFAS contamination for the public interest. Potentially contaminated sites could therefore be prioritised by governments to conduct sampling campaigns and tailor action plans to protect the public.

The full methodology

The full methodology can be found via Le Monde here.

Map Dataset | Expert Dataset

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