Glyphosate lessons: is biodegradation of pesticides a harmless process for biodiversity?

Abstract

The historical perspective on the rapid biodegradation of pesticides as a mitigating factor in environmental risk assessment is reexamined through the example of glyphosate and its implications for freshwater biodiversity. Commonly employed standardized methods by national agencies for assessing the environmental risk of pesticides predominantly rely on single-species tests, overlooking the intricate nature of ecosystems. Glyphosate, one of the most widely used pesticides marketed for its purported rapid biodegradability, is often perceived as relatively innocuous. However, its degradation releases phosphorus into the environment, inducing a trophic state shift in water systems towards more eutrophic conditions, consequently affecting water quality. These findings highlight the cascading ecological repercussions of glyphosate biodegradation, driving the proliferation of specific aquatic organisms, such as picocyanobacteria and metaphyton, resulting in the alteration of ecosystem structure and dynamics. The study explores challenges posed by commercial pesticide formulations and investigates the consequences of pesticide interactions with specific anthropogenic factors. A case in point is the interaction of glyphosate with the invasive mussel Limnoperna fortunei, exacerbating the overall scenario. The ecological framework analyzed challenges the conventional notion that pesticide biodegradation is inherently a neutral or positive event. The results underscore the necessity of reassessing the role of biodegradation itself in environmental impact assessments for pesticides.

Hormesis, the Individual and Combined Phytotoxicity of the Components of Glyphosate-Based Formulations on Algal Growth and Photosynthetic Activity

“…Significant differences were demonstrated in the individual and combined toxicity of the components presented in the tested GBHs. Furthermore, our results support the scientific opinions proposing changes in the official regulations, including the strict regulation of co-formulants, the future development of standards to assess combined effects, and the environmental risks of chemical mixtures [ 136 , 137 ]. Generally, the active ingredients and the co-formulants almost certainly become separated relatively quickly after pesticide treatments.…”

Ecotoxicological Evaluation of Safener and Antimicrobial Additives in Isoxaflutole-Based Herbicide Formulations

“…Due to the increasing application rates of isoxaflutole accelerated by the cultivation of isoxaflutole-resistant GM soy, its chemical load on the environment increases, yet environmental accumulation risk has not been attributed to the a.i. In cases of severe environmental pollution with pesticide a.i.s causing persistent or cumulating contamination, not only the environmental fate and toxicology of the substance, but potential means of remediation are needed to be assessed, as seen, e.g., in the case of paraquat [ 40 ] or glyphosate [ 32 , 41 , 42 ]. The environmental status of isoxaflutole is fortunately not as unfavorable, apparently manageable by certain application restrictions, and therefore the feasibility of remediation is uncalled for.…”