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How much environmental research is available about glyphosate?

Category: Environment and Wildlife

Hundreds of scientific studies have been conducted on this topic and published as peer-reviewed journal papers. Collectively, they form a substantial knowledge base that lets scientists and regulatory bodies draw conclusions about the potential risks of glyphosate-based herbicides to forest ecosystems and associated wildlife.

The scientific information base pertinent to environmental fate and effects of glyphosate-based herbicides is extensive. Peer-reviewed journal papers on these aspects including both laboratory and field studies number into the thousands, with a few hundred of these documenting studies conducted in forest ecosystems across Canada or in the northern USA, which can be considered most directly pertinent. The scientific knowledge base on fate and effects of glyphosate-based herbicides is quite arguably greater than that for any other forest-use herbicide, or any other alternative vegetation management technique. The primary literature, published in peer-reviewed scientific journals, has been reviewed by scientific experts and regulatory authorities both in Canada and internationally. Scientific reviews and risk analyses consistently conclude that when used in the accordance with product labels and applicable regulations, glyphosate-based herbicides do not pose a significant risk of harm to the environment or to wildlife. Results of studies conducted specifically in forest ecosystems pertinent to use in Canadian forest vegetation management are consistent with and support those general conclusions.

Scientific studies pertinent to the fate and effects of glyphosate-based herbicides have been published in the peer-reviewed scientific literature. This knowledge base includes both laboratory and field studies, conducted on a wide-variety of sub-topics, by a large number of academic, government and other scientists. Many environmental fate and ecotoxicology studies have been conducted in Canadian forest ecosystems including in the provinces of British Columbia, Alberta, Ontario, Quebec and New Brunswick. Much of the literature has been assessed in independent regulatory and scientific reviews and risk assessments (USDA-FS 1984; Grossbard 1985; Sullivan 1985; Lautenschlager and Sullivan 2002; USEPA 1993, Reynolds et al. 1993; WHO 1994; Williams et al. 2000; Giesy et al. 2000; Solomon and Thompson 2003; Durkin 2003; Tatum 2004; Sullivan and Sullivan 2003; Couture et al. 1995; Guynn et al. 2004; Thompson 2011, PMRA 2015). The general conclusion, drawn consistently from all of these reviews and risk assessments, is that when used in accordance with product labels and applicable regulations, glyphosate-based herbicides do not pose a significant risk of harm to the environment or to wildlife.

In April 2015, the PMRA released their latest review of glyphosate and declared that the weight of evidence indicates that glyphosate does not present unacceptable risk to human health. The full PMRA glyphosate review can be found here or please visit here for a summary version of the full PMRA review.



USDA-FS. Pesticide Background statements. Volume 1: Herbicides. United States Department of Agriculture Agricultural Handbook #633: United States Department of Agriculture - Forest Service. pp. 1-72. 1984.

Grossbard E, Atkinson D. The Herbicide glyphosate. London: Butterworths 1985.

Sullivan, T.P. Effects of glyphosate on selected species of wildlife. In The herbicide glyphosate. Edited by E. Grossbard, and D. Atkinson. Butterworths, London, U.K.1985; pp. 96–125.

Lautenschlager, R.A., and Sullivan, T.P. Effects of herbicide treatments on biotic components in regenerating northern forests. For. Chron. 2002; 78: 1–37.

United States Environmental Protection Agency. Re-registration Eligibility Decision (RED): Glyphosate. In: Agency EP, editor. Washington, D.C.: Office of Prevention, Pesticides and Toxic Substances (7508W) 1993. p. 291

Reynolds PE, Scrivener JC, Holtby LB, Kingsbury PD. Review and synthesis of Carnation Creek herbicide research. For. Chron. 1993; 69(3):323-30

World Health Organization. International programme on chemical safety. Environmental health criteria 159 - Glyphosate. Geneva, Switzerland: World Health Organization 1994.

Williams GM, Kroes R, Munroe IC. Safety evaluation and risk assessment of the herbicide Roundup and its active ingredient, Glyphosate, for Humans. Reg. Toxicol. Pharm. 2000; 31:117-65.

Giesy JP, Dobson S, Solomon KR. Ecotoxicological risk assessment for Roundup® herbicide. Rev. Environ. Contam.Toxicol. 2000; (167):35-120.

Solomon KR, Thompson DG. Ecological risk assessment for aqautic organisms from over-water uses of glypohsate. Journal of Toxicology and Environmental Health. 2003; 6:289-324.

Durkin PR. Glyphosate - Human health and ecological risk assessment report. Syracuse Environmental Research Associates Inc, Fayetteville NY 2003.

Tatum V. The toxicity of silvicutural herbicides to wildlife - volume two: Glyphosate and Imazapyr. NCASI Technical Bulletin. 2004(886):81.

Sullivan TP, Sullivan DS. Vegetation management and ecosystem disturbance: impact of glyphosate herbicide on plant and animal diversity in terrestrial systems. Environ. Rev. 2003; 11:37-59.

Couture G, Legris J, Langevin R, Laberge L. Evaluation of the impacts of glyphosate as used in forests (English abstract, French text). Ministere des Ressources naturelles, Direction de l'environnement forestier, Publ No RN95-3082. 1995:187.

Guynn DC, Guynn ST, Wigley TB, Miller DA. Herbicides and forest biodiversity - what do we know and where do we go from here? Wildlife Society Bulletin. 2004; 32(4):1085-92.

Thompson DG. Ecological impacts of major forest use pesticides. Chapter 5, In: Sanchez-Bayo, F., P. van den Brink and R.M. Mann (Eds.). Ecological impacts of toxic chemicals. Bentham Science Publishers Ltd. 2011; pp 88-110.

PMRA (Pest Management Regulatory Agency). Proposed re-evaluation decision – Glyphosate. PRCD2015-01. 13 April 2015. Available electronically at: pmra.publications@hc-sc.gc.ca