Glyphosate Feedback

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It is very true that adults are concerned about chemical exposures in their environment and everyday consumer products. For what its worth: The story of EPSPS inhibition is often oversimplified, there is also feedback regulation, pathways in some microbiota not intact or lack integrity, and minimum inhibitory concentrations (MICs) are needed to fully understand. All of these influence the potential for biological response. (Enzymes are 3-deoxy-d-arabino-heptulosonate-7-phosphate synthase (DAHPS), chorismate mutase, and tryptophan synthase, doi.org/10.3390/catal15…)

While “the dose makes the poison” remains the public’s default toxicology phrase, our science has advanced far beyond this 16th‑century aphorism. Similarly, reliance on LD₅₀ values is largely outdated. Dependence on exposure route and species differences make it pretty non-useful. I could point to DDT being an illustrative case of low acute yet notable chronic and ecological toxicity.

The recent circulation of an unpublished Food and Water Watch study is disappointing. With the often‑cited Agricultural Health Study (AHS), I’m probably alone, but can agree that it remains the most statistically powerful of the epidemiological studies, yet I find its conclusions overvalued given confounding exposures inherent in design. See Coble doi.org/10.1038/sj.jea.…

Studies on gut health, such as the Brazilian microbiome paper, indicate local microbial effects; however, shotgun metabolomic data suggest these subtle effect may not translate into any measurable systemic disturbances ”limited consequences on physiological biochemistry”. doi.org/10.1289/ehp6990

There is little doubt that dietary exposure to glyphosate is ubiquitous - full stop - depends on methodology, more sentitive would show 💯

The IARC Monograph Program should not be conflated with regulatory bodies. I’d push back against the simple hazard v risk characterizations, as regulatory agencies also start with a hazard assessment using the same (+ more) underlying data and studies. Major differences lie in access to all data, including studies often required for registration & conducted under GLP (& often by 3rd parties). Quantitative risk characterizatons using older methods or benchmark dose software then adds FQPA safety factors 10×10×10 (for interspecies/intraspecies variability, and infants/children when appropriate). These are outside the competency of monograph program as acknowledged by IARC itself under the working group formerly led by plaintiff expert Christopher Portier. monographs.iarc.who.int… Unfortunately, courtroom discourse seldom examines risk at sub-limit doses (1000 mg/kg/day) and skills of the questionare (lawyers) are lacking that can result in multi-billions dollar verdicts and settlements.

Glad that regulatory agencies including the U.S. EPA, EFSA, Health Canada, and their counterparts in Australia and Japan are mentioned, that is something frequently omitted from popular coverage. See the glyphosate factsheet - efsa.europa.eu/sites/de… -

“It is the most comprehensive and transparent assessment of a pesticide that EFSA and the EU Member States have ever carried out, taking into account thousands of studies related to human and animal health and the environment, and involving dozens of scientists from EFSA and national authorities across Europe.”

However, I would caution against any overreliance on EPA’s ADI or EU acute benchmark values given their basis in animal observational clinical endpoints. Playing worst case, steelmanning if you were, using the California OEHHA NSRL of 1,100 µg/day that connects to ‘duty to warn’ and comparison to dietary levels.

Finally, while spray drift remains a legitimate concern with dicamba formulations, it is not clear concern or characteristic of glyphosate. Numerous studies (including several in Nature publications) document drift physics and buffer‑zone effectiveness that is core to current EPA herbicide policy frameworks. Runoff may be a different story in some cases. epa.gov/soil-fumigants/… — also Herbicide Strategy - EPA - downloads.regulations.g…