The final report, 1000 pages, leaves no room for doubt. “All terrestrial, aquatic and marine environments – particularly coastal – are contaminated by plant protection products, indicate the National Institute for Agronomic Research (Inrae) and the French Research Institute for the Exploitation of the Sea (Ifremer Direct and indirect impacts of these substances have also been proven on ecosystems and populations of terrestrial, aquatic and marine organisms”.
To reach this conclusion, 46 experts from 19 different research organizations – mandated in 2020 by three ministries (Energy Transition, Agriculture and Research) – combed through more than 4,000 scientific publications relating to France or comparable territories for two years. This work, which combines very diverse research fields – essentially ecotoxicology, but also addressing environmental chemistry, biology, ecology, economics, sociology or law, echoes the Inserm report in particular. Made public on June 30, 2021, it focused on the effects of pesticides – used to control undesirable plant species (herbicides) and against organisms deemed harmful (insecticides and fungicides) – on human health.
Each year, between 55,000 and 70,000 tonnes of active plant protection substances, including those usable in organic farming and biocontrol, are sold in mainland France and overseas and are used for crop protection or maintenance. gardens, green spaces and infrastructure. This meta-analysis – a study of all the scientific literature on a subject – therefore offers a precise mapping of the various territories in France and the overseas territories affected by these substances. A welcome work, since the last work on the subject dates back to 2008 and 2005, which is based on “the densification of the monitoring network, but also on the improvement of sampling or analysis techniques”, specified Wilfried Sanchez, deputy scientific director of Ifremer, during a press conference which took place on Thursday 5 May.
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The researchers came to a clear conclusion: plant protection products have been found in all environments, even if their concentration is highly variable. “The contaminations of molecules are plural, since they involve a diversity of active substance, but also the transformation products of these substances, as well as the adjuvants, further indicated Wilfried Sanchez. This contamination affects all environments, but is preferentially found in agricultural areas, therefore close to areas of use”. And if the pollutants are mainly present in the fields and their surroundings, they then diffuse “along the land-sea continuum, from streams to rivers, to the sea or the ocean, with a gradual decrease due to However, some molecules are found in concentrations considered high, such as glyphosate, a famous controversial herbicide, “detected in certain coastal areas in concentrations of the order of a microgram per litre, i.e. approximately 100 or even 1000 times more than other phytopharmaceutical molecules”, detailed the research director.
The concentration also decreases over time, but it sometimes persists for years, as evidenced by the presence of various products banned long ago (DDT, lindane, diuron), which are found hundreds or even millions of kilometers from their area of use, for example in sediments or organisms that live up to 3000 meters deep, or even in the polar circle, in the Kerguelen Islands.
Biodiversity in danger: a future regulation to foresee?
Another finding appears in this report: plant protection products endanger biodiversity, even if it is also attacked by other factors, including global warming, the exploitation of resources or the destruction of natural habitats. “Available studies published over the past 20 years allow us to assert in a robust way that plant protection products are one of the major causes of the decline of certain populations”, underlines Stéphane Pesce, specialist in ecotoxicology at Inrae. The researchers note that in certain ecosystems, such as small streams near agricultural areas, up to 40% of species can disappear, in particular terrestrial invertebrates, including pollinating insects such as bees or beetles that prey on certain pests, as well as birds. Some of the synthetic products “contribute strongly to the risk” of extinction which weighs on 9 to 15% of the species listed in Europe”, he underlined.
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The objective of this expertise, in addition to informing the general public, was to “make visible and intelligible, for public decision-makers, all the knowledge to inform decisions and improve regulations”, explained Thierry Caquet, Scientific Director Environment of INRAe. It should in particular guide the government, in full reflection on the use of pesticides, in particular glyphosate, which was banned, then finally extended and which remains, to this day, suspended, since the European Union must decide its fate. by the end of this year.
Victor Garcia
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