The quality of water in rivers and groundwater has been improving for several years in the south-east of France, but the more detailed detection of new pollutants with unknown effects does not allow us to really rejoice. This is, in essence, the paradoxical picture of “the state of the waters”delivered Wednesday November 6, to Lyon, by the Rhône-Mediterranean-Corsica basin water agency. According to this study, 48% of the rivers in the south-east of France are in “good ecological status”. This indicator of overall good health rises to 52% for the Auvergne-Rhône-Alpes region, and 91% for Corsica.
“Many parameters are improving, the natural environment functions better, it is more resilient, and we can have confidence in the fact that we can continue to progress,” notes Nicolas Mourlon, director general of the water agency, which aims to achieve the objective of 67% of watercourses in good ecological condition in 2027. In general, water quality is better in areas mountainous, more degraded near towns and intensive activities, and excessive development of waterways does not contribute to good biodiversity.
This optimistic version is based on the analysis of 1,400 chemical and biological parameters, recorded in a total of 1,900 stations of rivers, groundwater, coasts and bodies of water. Thus, organic pollution has been in constant decline for fifteen years. The presence of ammonium (NH4), often coming from the use of cleaning products, has been divided by twenty in thirty years. Good news for aquatic fauna, as this substance can very quickly transform into toxic ammonia under the effect of climatic heat.
Increase in the presence of pesticides
Another encouraging indicator: the division by ten of phosphorus concentrations in the 11,000 waterways of the Rhône-Mediterranean-Corsica basin since 2007, the date of the ban on phosphate in household textile detergents. In the category of micropollutants, other results are positive concerning polycyclic aromatic hydrocarbons (PAHs), or pesticides, whose toxic impact has significantly decreased over the last fifteen years.
Concerning pesticides, however, the water agency report issues an alert. Since 2021, the presence of pesticides of most likely agricultural origin has started to increase again due to the use of cypermethrin, a classified insecticide “very toxic for the environment”. Rivers are affected in the Beaujolais (Rhône), Dombes (Ain), and Valence (Drôme) sectors.
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