Neonicotinoids have been prohibited in France for several years but an LR bill, studied from this Monday in the hemicycle of the National Assembly, could reintroduce subject to one of them, acetamipride. This insecticide, harmful for bees, is claimed by the beet or hazelnut sectors, which believe that they have no other weapon.
What concerns?
In terms of human health, neonicotinoids pose a classic problem concerning pesticides: these substances, intended to kill insects, also harm us by their mechanisms of action?
The specificity of neonicotinoids is to target the nervous system. Above all, they arouse questions about their neurological effects, in particular their potential role in neurodevelopment disorders in children and adolescents.
But researchers have also looked into other risks: how do neonicotinoids play on our hormones, as endocrine disruptors? Are they associated with a higher risk of cancer?
What do we know?
The current consensus, as given by the scientific literature and various health authorities, is largely summed up with uncertainty, sometimes accompanied by calls for the precautionary principle.
“Major uncertainties” remain on the neurodevelopmental effects of acetamipride, summed up in 2024 in 2024 the European health agency, EFSA.
It would take “new elements” to be able to “adequately assess the risks and dangers” of acetamipride, insisted the agency, calling for the time to clearly lower the thresholds to which this pesticide is deemed potentially dangerous.
What studies do we have?
“Neonicotinoids are pesticides that have been little studied on their effects for humans,” Sylvie Bortoli, toxicologist at Inserm, told AFP. “The bibliography remains fairly incomplete compared to other emblematic pesticides such as DDT or glyphosate.”
A corpus of research has existed for several years. It essentially mixes “in vitro” work, which describes what happens when a cell is exposed in the laboratory to neonicotinoids, studies on animals, generally mice.
The first type of study (known as mechanism) has notably shown the deleterious effects of neonicotinoids on neurons. The second category highlighted their action in neurological disorders, but also in other pathologies. A study, published in 2022 in the journal Environment International, thus showed the capacity of acetamipride to cause breast cancers in mice.
If these studies support the idea that neonicotinoids have potential risks, they do not allow to definitively conclude that they really play a role in human pathologies, at least at the level at which these products are used in real life.
How to know more?
Researchers agree on the need to conduct more epidemiological studies. Such studies assess, within a group of people, the frequency of certain disorders according to the more or less large exposure to a given factor, here neonicotinoids.
“There is a crucial need for large -scale epidemiological studies to clarify the effects that exposure to neonicotinoids could have on health,” summarized in 2022 a synthesis of knowledge, in the journal Environment International.
These studies would bring important elements to know if toxicity, measured in the laboratory or on animals, is actually translated into health problems in the population. And, in this case, they would make it possible to better assess the risk according to the type of exposure: in farmers, in people living close to farms, among consumers of food treated with neonicotinoids …
Admittedly, “there are some recently published epidemiological studies, but they are few and not necessarily concordant,” notes Ms. Bortoli.
A study, published in 2017 in the journal Environmental Health Perspectives, for example points to a less good intellectual development of children whose mothers have passed their pregnancy near operations using neonicotinoids. But the sample remains limited – around 300 Californian families – and other works would be necessary to confirm this effect.