Collaborating with Le Monde to map the status of groundwater in France


Over the past months, IGRAC has assisted Le Monde in its investigative journalism on groundwater contamination in the European Union. After last year’s ‘Forever Pollution’ project, a cross-field investigation by 16 European newsrooms on PFAS across Europe, Le Monde decided to keep the spotlight firmly pointed at groundwater contamination by joining the ‘Under the Surface’ project. Today, it published some of its outcomes in a news article, as well as an interactive map, with the contribution of IGRAC.

Three hundred contaminants in our aquifers

In the article “Three hundred contaminants in our aquifers: pollutant by pollutant, our analysis of groundwater in France”, Le Monde journalists Léa Sanchez and Raphaëlle Aubert have compiled data on 300 contaminants (including pesticides, metals, and pharmaceuticals) from 24,700 monitoring stations.

The interactive map (developed by cartographer Elsa Delmas) visually represents the extent of pollution affecting aquifers in France, monitored by the selected 24,700 groundwater monitoring stations. From the millions of data points collected between 2016 and 2023, over a quarter (28%) recorded at least one instance of contamination exceeding the threshold values set by regulatory authorities. 

IGRAC’s contribution to Le Monde publication

The article also covers the quantitative status of groundwater. IGRAC used groundwater level data from the reference monitoring stations available in France in order to calculate statistical trends over the period 2000 – 2022, spanning from the adoption of the Water Framework Directive until its last reporting phase. The methodology used to calculate the trends is the one that we developed for the global assessment of groundwater levels in the World Meteorological Organization report on the State of Global Water Resources. The detailed methodology can be consulted on the IGRAC GitHub account.

Nearly 2000 monitoring stations met the data selection criteria. A significant negative trend was identified in some 700 of them, while a significant positive trend was identified in only some 300 of them. The remaining monitoring stations did not show any significant negative or positive trend, meaning that the groundwater levels are at equilibrium or that the variations in groundwater levels do not exhibit a distinctive declining or rising pattern.