Backgrounder

                                          Authoritative sources for glyphosate information

                                          July, 2002



Monsanto Company



Glyphosate has been the subject of hundreds of toxicological and environmental studies during

the nearly 30 years of use. Because glyphosate products are used in so many different ways

(agriculture, ornamental, aquatics, wildlife habitat, residential etc.), glyphosate is perhaps the

most studied of any herbicide molecule. Many scientists � from industry, governmental

agencies, universities and independent institutions � have conducted experiments, laboratory

studies and field research with glyphosate herbicides.



To get a clear picture of the environmental and toxicological characteristics of the products, it is

important to consider the total weight of evidence provided by this extensive body of research.

The U.S. Environmental Protection Agency (EPA), Health Canada, the European Commission

(EC) and many other regulatory bodies and science organizations, such as the World Health

Organization (WHO) have reviewed this data. Their overwhelming consensus is that glyphosate,

when used according to label directions, poses no unreasonable risk to people, wildlife or the

environment.



The most recent review was conducted by the European Commission’s Health and Consumer

Protection Directorate-General, after which glyphosate was re-registered for use in Europe (Jan.

21, 2002). The EC review, like others around the world, concluded that glyphosate is not

carcinogenic and has favorable toxicological properties, which are listed in tables for public

access at http://europa.eu.int/comm/food/fs/ph_ps/pro/eva/existing/list1_glyphosate_en.pdf.



The EPA and WHO have published two authoritative documents. In addition, two international

panels of independent experts published peer-reviewed safety evaluations of glyphosate.

Another summary report was compiled by EXTOXNET, a cooperative effort of extension

toxicologists from several universities. All these summaries conclude that the weight of evidence

shows very low risk to human health and the environment when the product is used properly.



Here are some quotations from four major works that assess the overall glyphosate weight of

evidence:



EPA Reregistration Eligibility Decision: Glyphosate (September 1993):

Fact Sheet: http://www.epa.gov/oppsrrd1/REDs/factsheets/0178fact.pdf

Full RED: http://www.epa.gov/oppsrrd1/REDs/old_reds/glyphosate.pdf



   �   “Glyphosate is of relatively low oral and dermal acute toxicity.�

   �   “Exposure to workers and other applicators generally is not expected to pose undue

       risks, due to glyphosate's low acute toxicity.�

   �   “Several chronic toxicity/carcinogenicity studies…resulted in no effects…or resulted in

       findings that glyphosate was not carcinogenic in the study. In June

       1991, EPA classified glyphosate as a Group E oncogen--one that shows evidence of

       non-carcinogenicity for humans.�

   �   “Glyphosate does not cause mutations.�





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   �   “Human dietary exposure and risk are minimal.�

   �   “Glyphosate adsorbs strongly to soil…residues are expected to be immobile in soil.�

   �   “Glyphosate is readily degraded by soil microbes to AMPA, which is degraded to carbon

       dioxide.�

   �   “Based on current data, EPA has determined that the effects of glyphosate on birds,

       mammals, fish and invertebrates are minimal.�



WHO Environmental Health Criteria 159: Glyphosate (1994):

http://www.inchem.org/documents/ehc/ehc/ehc159.htm



   �   "Long-term toxicity was studied in mice and rats. Few effects were observed and, in almost all

       cases, at relatively high dose levels only."

   �   "Glyphosate, administered by oral and dermal routes, has a very low acute toxicity."

   �   "Animal studies show that glyphosate is not carcinogenic, teratogenic or mutagenic."

   �   "Possible hazard for most aquatic organisms is small or negligible. Fish and aquatic

       invertebrates would not be affected by glyphosate use."

   �   "Test data show low toxicity of glyphosate and its formulations to honey-bees, earthworms, birds

       and mammals."



“Ecological Risk Assessment for Roundup Herbicide� (Giesy, et al., 2000): *



   �   “Field studies indicate that glyphosate typically dissipates rapidly from both simple

       ecosystems, such as agricultural, and more complex ecosystems, such as forestry.�

   � “Glyphosate does not bioconcentrate in fish or other animals.�

   â€? “â?? minimal risk…would be expected for sediment dwelling organisms.â€?

   � “�Roundup poses minimal risk to aquatic organisms.�

   � “�the literature supports the conclusion that non-target arthropods (insects, spiders,

       mites) are at minimal risk from glyphosate and its formulations.�

   � “Several comprehensive field studies have observed birds in forest plots treated with

       Roundup� In no case was there evidence of direct toxicity of Roundup or glyphosate to

       birds.�

   � “It has been concluded that there is minimal risk to small mammals from the application

       of glyphosate products.�

   Click here for a summary of the Giesy review.



“Safety Evaluation and Risk Assessment of the Herbicide Roundup and Its Active

Ingredient, Glyphosate, for Humans� (Williams et al., 2000): **

URL: http://dx.doi.org/10.1006/rtph.1999.1371



   �   “Roundup is placed in U.S. EPA’s least toxic category (IV) for acute oral, dermal and

       inhalation toxicity. Thus, the Roundup formulation is considered to be practically

       nontoxic by all these routes of exposure.�

   �   “Results from several studies have established that glyphosate is not a reproductive or

       developmental toxicant.�

   �   “There is no evidence that…Roundup adversely impacts reproductive function.�

   �   “There was no suggestion of increased severity of effect in infants or children or of

       increased potency or unusual toxic properties of glyphosate in infants and children.�









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   �   “The use of Roundup herbicide has no potential to produce adverse effects on endocrine

       systems in humans nor in other mammals.�

   Click here for a summary of the Williams review.





Another excellent resource is EXTOXNET, a cooperative effort of University of California-Davis,

Oregon State University, Michigan State University, Cornell University, and the University of

Idaho. A glyphosate summary is available on-line at

http://ace.ace.orst.edu/info/extoxnet/pips/ghindex.html.









* Review by John P. Giesy, Stuart Dobson and Keith R. Solomon, published in Reviews of

Environmental Contamination and Toxicology, (2000) Vol. 167, pp. 35-120. The publication was

based on their review of more than 250 documents.



** Review by Gary M. Williams, Robert Kroes and Ian C. Munro, published in Regulatory

Toxicology and Pharmacology, (2000) Vol. 31, pp. 117-165. The publication was based on their

review of nearly 200 documents.









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