Are pesticides dangerous to living organisms? ? At the request of the government, forty-six researchers worked on the issue for two years ; they compiled, compared, and analyzed more than 4,000 studies. The answer, published on Thursday 5 May, is in three letters: yes, they pollute all environments and weaken biodiversity. This observation is not new, but it is now supported by solid scientific expertise.
“ This is an inventory of existing knowledge », specifies Sophie Leenhardt, a researcher at the National Research Institute for Agriculture, Food and the Environment (Inrae), who has carried out the work of the French Research Institute for the Exploration of the Sea (Ifremer). The last collective expertise of this magnitude dates back to 2005. The goal according to Mme Leenhardt: “ Inform the debate and public action without giving an opinion or formulating recommendations. » At a time when the French state is wondering how the millions of euros of the CAP will be allocated, this document nevertheless contains condemnatory elements against intensive agriculture.
Widespread pollution of ecosystems
The report highlights “ widespread ecosystem pollution » of pesticides, especially in agricultural areas. Every year, between 55,000 and 70,000 tonnes of active phytopharmaceuticals are sold in France … a large part of which therefore ends up in the environment. This pollution “ affects all media – soil, air, water – and involves a variety of substancessays Wilfried Sanchez, vice president of Ifremer. We find the active substances in pesticides, but also their transformation products and their excipients. »
For example, glyphosate, one of the best-selling herbicides, is used with additives to increase its effectiveness. ; and when the product degrades, a new, equally toxic molecule, Ampa, is created. “ Plant protection products are found even in the oceans, along the coasts, but also in the seabednotes Mr Sanchez. We even found DDT [un insecticide interdit en France depuis 1972] hundreds of kilometers away, in areas close to the poles. » A small consolation, the banned products see their concentration drop little by little.
- Involuntary glyphosate pisses show the concentration of the herbicide in their urine in 2018. © Julie Lallouët-Geffroy / Reporter
However, it is still difficult to quantify the degree of pollution. “ The diversity of the substances analyzed remains limited in terms of those potentially present – 294 active substances and more than 1,500 commercial preparations are currently authorized in Franceinsists the report. Many substances have not been studied, especially among the most recently brought to market. » The only certainty: this widespread contamination interferes with many living organisms – even in human urine.
Amphibians and dolphins would get sick more easily
Not surprisingly, this impregnation weakens everything alive. First threatened, those who live not far from the fields: bees, bumble bees, ladybirds, butterflies, birds … “ Available studies confirm that plant protection products are one of the main causes of population decline. » insects, birds, invertebrates…, summarizes Stéphane Pesce, researcher in ecotoxicology at Inrae. “ On a European scale, it is estimated that pollution will cause losses of up to 40 % in macro-invertebrates [larves ou mollusques] aquatic. »
These chemicals do not just kill living beings. “ They have many sub-lethal effectsMr Pesce points out, that is, they disrupt the organism »without being fatal. Loss of orientation, immune deficiency, alteration of reproduction … “ More and more unexpected effects without a clear relation to the known mode of action are highlighted, for example with regard to the nervous system, immune system, endocrine systems or even interactions with microbiota. », the report notes. Amphibians and dolphins would get sick more easily.
Hedge planting and wetland restoration
Researchers also highlight a butterfly effect: by suppressing insects or destroying part of the vegetation, insecticides and herbicides reduce the food resources and habitats of many animals, including certain birds. Pesticides “ act as an aggravating factor in the health of ecosystems, ranked fourth among the factors that weigh on nature globally », the report recalls. In 2019 becameIPBESthat “ Biodiversity IPCC », warned of the possible extinction of one million species, partly due to chemical pollution. Pesticides would be too “ first engine » the decline of insects, specified a parliamentary study published in January last year.
What to do ? The collective expert assessment does not include the topic, other work is underway. She nonetheless mentions a few action handles. “ The first lever to reduce pollution is to reduce the amount of plant protection products used », reads the report. Alas, the policies implemented so far have been shown to be ineffective in getting rid of pesticides. Researchers list promising paths, such as planting hedges and restoring wetlands to create “ buffer locations » able to absorb and degrade some of the substances.
On the regulatory side, the two research institutes point to significant progress. Because, though “ European rules in this area are one of the strictest in the worldexplains Laure Mamy, researcher at Inrae, it has limits ». The authorities responsible for approving (or not) products do not adequately analyze the cocktail effects – the consequences of combined exposure to multiple substances – or the chain effects of a product on an entire ecosystem. “ Need a more systemic approach »insists M.me Grandmother. While European authorities are preparing to re-authorize glyphosate, this scientific report should sound like a warning.