Japanese scientists from the University of Tokyo recently made a worrying discovery. Residues from several insecticide substances belonging to the famous family of neonicotinoids were detected in rainwater. In Japan, neonicotinoids were introduced en masse in the 1990s, in particular in the fields of rice culture and in pine forests. Withdrawn and analyzed rainwater samples from cities of Tsukuba and Kashiwa, both located northeast of Tokyo.
The analyzes were carried out between April 2023 and September 2024. They reveal that 91% of the samples contained several insecticides of the family of neonicotinoids. “”The highest total concentration was detected in August 2024“, note the authors of the work. Acetamipride is the main insecticide, since it was identified in 82%of the samples, followed by Thiaclopride (73%) and Dinotéfurane (45%), two other insecticides of the family of neonicotinoids.
“”This research is the first report on the presence of neonicotinoids in precipitation, suggesting that neonicotinoids, as a little volatile material, can still be dispersed in the environment via precipitation“, Alert researchers, whose work is published in the Environmental Monitoring and Contaminants Research journal.
Potential effects on human health
In 2019, another study (also carried out by researchers from the University of Tokyo) published in the journal Science explained in detail how large-scale spreading of neonicotinoids contributed to the destruction of several species of fish, crustaceans and Zooplankton in Lake Shinji, (South-West of Japan). From 1993, several rice farmers began to spread imidaclopride in their fields. According to the study, the introduction of this insecticide in areas geographically close to the lake coincided with an 83% decrease in the average zooplankton biomass.
If the harmful effect of neonicotinoids on insects (notably bees) and several other animal species is increasingly documented, the doubt remains with regard to human health. Since neonicotinoids target the nervous system, scientists fear (among others) that exposure to these substances can be associated with neurological disorders. But these risks are currently uncertain, for lack of large -scale studies devoted to the subject.