Juline Garnier / Photo credit: CHRISTOPHE RAVIER / BIOSGARDEN / BIOSPHOTO VIA AFP 6:00 a.m., March 22, 2024

In 2019, in France, among the 10,714 bodies of water analyzed, 43.8% were “in good chemical condition”, according to the public water information service. But what is behind this figure? On the occasion of World Water Day, Europe 1 focuses on the monitoring of pollutants present in French waterways.

Intensive agricultural practices, domestic and industrial discharges, accumulation of waste... The French hydrographic network is fragile and its monitoring constitutes a major challenge, both for health and for the environment. One of the greatest concerns of public opinion in recent years has been the presence of pollutants in waterways. From phosphorus in the 1990s to heavy metals more recently, the presence of several pollutants in rivers regularly resurfaces in the news and calls for public action.

The latest: the worrying rate of so-called “eternal” pollutants in French rivers. According to a study by the NGO Générations futures, this type of chemical substance has been found in rivers, lakes and ponds in almost the entire country. Out of 13,000 samples analyzed in 2020, 4 out of 10 were contaminated. If they are at the top of the list of analysts' concerns, we should not be alarmist, adds Émilie Lance, ecotoxicologist and specialist in freshwater pollution.

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Slow diagnosis and lack of perspective

"We are still in the diagnosis phase. There is necessarily a concern because these substances called 'pops' - for persistent organic pollutants - degrade very slowly, over tens or even hundreds of years. They are mobile, toxic , bioaccumulative and for certain carcinogens such as PAHs. If concerns exist, we are not yet able to give the scale of importance", explains the teacher-researcher. 

A slow diagnosis because scientists lack perspective: the families of pollutants are numerous and some have only been used for around twenty years, in addition to a danger that is still poorly understood. Most of them, like dioxins or PCBs, are “probable” carcinogens. For French and European agencies, research priority is given to monitoring the "cocktail effect" of substances present in water and to evaluating the exposome, i.e. the exposure of biota and man to these pollutants and the potential consequences.

© Data and statistical studies service

The IPTC, a new index to measure the intensity of cumulative toxic pressures.

“Poorly documented” reports?

However, many associations denounce the lack of action from French and European leaders. In an information note dated April 20, 2023 concerning the analysis of the risks of the presence of PFAS, which fall into the family of “eternal pollutants” – analysis led by the General Inspectorate of the Environment and Sustainable Development – ​​the Robin des Bois association, and criticizes the authorities for “poorly documented” reports. 

"The report does not mention PCBs and other very persistent substances such as organobromines. Isolating PFAS and putting them exclusively in the window of industrial abuses means succumbing to the mania of the Top Ten and giving up taking into account the cocktail effect of all immunosuppressive, endocrine disrupting, carcinogenic, mutagenic and reprotoxic poisons,” she explains. 

“The problem is that in accordance with an old, typically French habit of retention, the names of the river and the commune in these documents were partially blurred and the communities and populations concerned were not informed at the time of their publication,” the association even puts forward, speaking of “a shared omerta between the scientific world and the political world”.

“It’s going in the right direction, but it takes time”

Two realities therefore face each other, between urgency and necessary slowness: the impunity of polluters and the urgency of water in good condition in the face of the slowness of public actions and the time of perspective necessary for the scientific community to carry out its diagnoses. . 

“A lot of efforts have been made,” notes Émilie Lance, particularly in water treatment to reduce, for example, the share of heavy metals thanks to specific plants installed in retention basins which allow purification. Another example: the significant decrease in phosphorus levels in the 1990s.

Encouraging results also on the pesticide side. According to the General Commission for Sustainable Development, the trend index for the presence of pesticides in waterways between 2009 and 2014 fell by around 10%, thanks in particular to the ban on several substances. There is a real change in mentality, an awareness, welcomes Émilie Lance. “With regulations and awareness, things are going in the right direction, but it takes time, it will perhaps improve in the next ten years,” concludes the ecotoxicologist.