The quality of river water and groundwater has been improving for several years in the south-east of France, but the more detailed detection of new contaminants with unknown effects does not allow us to be really happy. This is, in essence, the paradoxical image of “the state of the waters”delivered on Wednesday, November 6 in Lyon by the water agency of the Rhône-Mediterranean-Corsica basin. According to this study, 48% of the rivers in the southeast of France are in “good ecological status”. This indicator of good general health rises to 52% in the Auvergne-Rhone-Alpes region and 91% in Corsica.
“Many parameters are improving, the natural environment works better, is more resilient and we can be confident that we can continue to progress.” says Nicolas Mourlon, director general of the water agency, which aims to achieve the goal of 67% of waterways being in good ecological status by 2027. In general, water quality is better in mountainous areas, more degraded near cities and intensive and excessive activities. Waterway development 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 from the use of cleaning products, has been divided by twenty in thirty years. Good news for aquatic fauna, since this substance can be transformed very quickly into toxic ammonia under the effect of climatic heat.
Increased presence of pesticides
Another encouraging indicator: the tenfold increase in phosphorus concentrations in the 11,000 watercourses 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 in the case of polycyclic aromatic hydrocarbons (PAHs), or pesticides, whose toxic impact has decreased significantly in the last fifteen years.
As for pesticides, however, the water agency’s report raises a warning. Since 2021, the presence of pesticides of probable agricultural origin has increased again due to the use of cypermethrin, a classified insecticide. “very toxic for the environment”. The rivers are affected in the Beaujolais (Rhône), Dombes (Ain) and Valence (Drôme) sectors.
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