French rivers are polluted by detergents, insecticides, herbicides and drugs, with possible impacts on natural environments and human health, according to two joint studies by Ineris and the French biodiversity office (OFB).

They evaluated the concentrations of 141 organic contaminants on 1,600 sites on French rivers between 2016 and 2018. It emerges that “the vast majority of contaminants (122) did not show ecotoxicological thresholds being exceeded, or exceptionally on a number of limited number of sites (less than 5% of sites) ”, according to a joint press release.

Some very contaminated sites 

However, “for the 19 remaining contaminants, chronic impacts or sub-lethal effects on aquatic populations cannot be excluded”.

"These contaminants are essentially detergent residues (up to 95% of sites with thresholds exceeded), insecticides (up to 40%), herbicides (up to 25%) or drugs (up to 20%)", specifies the press release.

"On a few highly contaminated sites, the concentrations of certain compounds (detergent or biocidal residues) can exceed 10 or even 100 times the chronic impact threshold values, suggesting possible acute impacts on local biodiversity", point out warns Ineris (National Institute for the Industrial Environment and Risks) and the OFB.

Different sources of pollution 

These substances can come from domestic uses, industry, agriculture or transport and can be found in nature through the discharges of wastewater treatment plants or the leaching of agricultural or urban soils by rainfall.

These substances called micropollutants "are known or suspected for their harmful effects on human health or on ecosystems at very low concentrations", according to the press release. 

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Keywords: ofb, rivers, impacts, herbicides, insecticides, drugs, uses, environments, studies, french, substances, detergents, sites, contaminants, industry