|12 February 2019
THIRD WORLD NETWORK BIOSAFETY INFORMATION SERVICE
Dear Friends and Colleagues
US EPA Ignored Substantial Scientific Evidence of Glyphosate’s Genotoxicity
A new analysis has been published in the journal Environmental Science Europe entitled, ‘How did the US EPA and IARC reach diametrically opposed conclusions on the genotoxicity of glyphosate-based herbicides?’. Genotoxicity refers to a substance’s destructive effect on a cell’s genetic material. Genotoxins can cause mutations in cells that can lead to cancer. While the US Environmental Protection Agency (EPA) evaluates glyphosate as “not likely to be carcinogenic to humans” and not genotoxic, the WHO’s International Agency for Research on Cancer (IARC) considers glyphosate as “probably carcinogenic to humans” and genotoxic.
Compared to the EPA’s genotoxicity review, the paper says that the IARC review is grounded on more recent, more sensitive, and more sophisticated genotoxic studies, and more accurately reflects real-world exposures.
The paper shows that only by framing and constraining its genotoxicity assessment in a highly selective way was the EPA able to conclude that glyphosate was not genotoxic. It also demonstrates that the EPA disregarded substantial scientific evidence of genotoxicity of glyphosate and glyphosate-based herbicides (GBHs). Overall, the way pesticides are assessed for risk is not fit for purpose and exposes people and the environment to unacceptable risks. The paper explains that the EPA and IARC reached diametrically opposed conclusions on glyphosate genotoxicity for three primary reasons:
- The EPA relied heavily on unpublished regulatory studies commissioned by pesticide manufacturers, 99% of which found that glyphosate was not genotoxic, while the IARC relied on peer-reviewed published studies and public literature reports, 70% of which found that glyphosate was genotoxic.
2. The EPA focused its analysis on glyphosate in its pure chemical form (“glyphosate technical”). However, almost no one is exposed to glyphosate alone. Applicators and the public are exposed to complete herbicide formulations consisting of glyphosate plus added ingredients (adjuvants). The IARC considered a total of 118 genotoxicity assays on glyphosate technical, GBHs, and aminomethylphosphonic acid (AMPA), glyphosate’s primary metabolite. The EPA’s analysis encompassed only 51 of these 118 assays (43%). The IARC further analyzed another 81 assays exploring other possible genotoxic mechanisms, of which 62 (77%) reported positive results.
3. The EPA’s analysis was limited to typical, general population dietary exposures assuming legal, food-crop uses, and did not take into account nor address generally higher occupational exposures and risks. The IARC’s assessment encompassed data from typical dietary, occupational, and elevated exposure scenarios. Elevated exposure events caused by spills, a leaky hose or fitting, or wind are actually common for people who apply herbicides several days a week, for several hours, as part of their work.
The editor-in-chief of Environmental Sciences Europe and a co-author have offered a list of “lessons to be learned” from the paper for the risk assessment of pesticides and other chemicals (see https://doi.org/10.1186/s12302-019-0187-z). They recommend that studies relating to both glyphosate and glyphosate-based herbicide formulations be taken into account in risk assessments. Also, all studies used in the risk assessment and the data underlying them must be made public and available for independent scrutiny.
With best wishes,
Third World Network
131 Jalan Macalister
Websites: http://www.twn.my/and http://www.biosafety-info.net/
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