Recent research conducted by Boulos Samia and colleagues at Aix-Marseille University and CNRS in France has revealed that nine commonly used pesticides in grape cultivation have an environmental impact that may have been significantly underestimated. The study emphasizes the need to update the risk assessment criteria for these pesticides, particularly concerning their atmospheric behavior and degradation rates.
Those pesticides are the same pesticides typically used in the growing and harvesting of grapes. Nevertheless, they exceeded the two-day threshold for atmospheric half-lives set by the Stockholm Convention. Laboratory experiments produced thrilling outcomes. Their atmospheric half-lives varied, with Cyprodinil lasting only three days while Folpet was over a month. None of these nine pesticides complied with the two-day threshold. This classification means that they are particularly vulnerable to long-range atmospheric transport.
Our study demonstrates that these pesticide compounds adsorb onto atmospheric particulate matter. This process increases their half-lives, allowing them to move greater distances before degrading. Current European regulations only take into account the atmospheric lifetimes of pesticides in their gas phase. They ignore the new reality of what happens to these chemicals in particulate form.
“The limited understanding about how these pesticides endure in the lower atmosphere is alarming,” Samia stated. Traditionally, they have been looked at in their gas state, and this is how EU regulations are currently established. Our research has shown that these newer particles are far less reactive. Consequently, they are able to break down much more slowly.
The research focused on different degradation mechanisms and the formation of different toxic/non-commercially available molecules during the degradation of these pesticides. If a pesticide exhibits an atmospheric half-life exceeding two days, it may be classified as a persistent organic pollutant (POP). These compounds are turning out to be more toxic, more ubiquitous, and more persistent than we ever thought.
Global pesticide use has at least doubled since 1990, the UN Food and Agriculture Organization reports. As a result, opposition based largely on health and environmental impacts is spreading like wildfire. Samia highlighted the urgency of reassessing these chemicals, stating, “Together these experiments suggest that pesticides used in agriculture need updated regulatory frameworks that take into account their particulate phase behavior in the atmosphere.”
The results of this research may prove influential in shaping future pesticide regulation throughout Europe and possibly further afield. Experts are now urging further research into these chemicals. What’s increasingly bothering him and others is the failure of today’s safety models to account for how far these substances can spread and stay embedded in soil and groundwater.