Here, I relate what the journalist said in his article “Les pesticides néonicotinoïdes continuent à menacer les abeilles, même lorsqu’ils ne sont plus utilisés”. All quotes, originally in French, were translated by me.
This article concerns a study published on November 28, 2019 in the journal Science of the Total Environment by researchers led by Dimitry Wintermantel and Vincent Bretagnolle, both researchers at the Center for Biological Studies in Chizé. (Wintermantel et al. 2019) The researchers analyzed nectar and pollen taken from 300 rapeseed plots spread over the Plaine and Val de Sèvre workshop area. Samples were taken from these fields between 2014 and 2018, i.e. after the 2013 moratorium.
Despite the latter, they observed “no downward trend.” The researchers found traces of NNI in 43% of the rapeseed samples analyzed. They found imidacloprid in 70% of plots in 2014, 5% in 2015, 90% in 2016, 30% in 2017, to rise to 55% in 2018. The vast majority of traces were less than 1 part per billion . However, on 2 occasions in 2016, researchers reportedly found 45 parts per trillion of imidacloprid in the samples tested, which would be “five times the expected concentration of product in the nectar or pollen of treated oilseed rape.”
The researchers estimated, from a “conservative” model, that of the EFSA, that 12% of the plots were contaminated enough to kill 50% of the honeybees venturing there, this rate rising to 20% for bumblebees. and 10% for solitary bees. According to them, it could be related to the rains, the contaminations being more important in the rainy years and the NNI being soluble in water. S.Foucart recalls a study published in the Journal of Applied Ecology in March studying the contamination of NNIs in Switzerland and finding NNIs in 93% of samples taken from organic farms and 80% in areas of ecological interest. It also recalls the estimated impact on the 72 species of invertebrates studied.