Hot Topics in Ecology

Glyphosate herbicide: is it as safe as we thought?

Natalia Montero, Vincent Fauvelle, Andrew Banks, Sarit Kaserzon, Jochen F. Mueller (Ikerbasque; Aix-Marseille Université; University of Queensland)
  • Glyphosate is the most widely used broad-spectrum herbicide and is not as innocuous as once thought.
  • Studies reveal higher mobility of glyphosate in soils than expected and longer half-lives in soils and water.
  • Mortality of non-target organisms at glyphosate levels found in the environment are not expected, but sublethal effects have been observed at very low concentrations.
  • Regulatory authorities suggest there is no cancer risk to humans at realistic exposure levels, but studies on long-term effects are needed.
Glyphosate-based herbicides are widely used to control noxious aquatic weeds, raising concerns about contamination of aquatic ecosystems. Photo by N. Montero.

Glyphosate, the active ingredient of more than 750 herbicides, is the most widely used herbicide in Australia (15,000 tons/y) and worldwide (826,000 tons/y).

Glyphosate is considered environmentally safe due to its physico-chemical properties, presenting: (i) strong binding to soil; (ii) relatively rapid degradation; and (iii) potentially negligible risk to non-target organisms (mode of action specific to plants, fungi and some bacteria). However, studies reveal higher mobility of glyphosate in soils than expected and longer half-lives in soils (days-months) and water (<4-315 days).

Generally, acute effects are not expected at glyphosate levels found in the environment. However, several sublethal effects have been observed in different organisms (rats, fish, amphibians, invertebrates) at glyphosate concentrations below regulatory guidelines: hepatorenal damage, endocrine disruption, reproductive impairment, genotoxicity, morphological alterations, oxidative stress. Toxicity is species- and development-specific, with higher toxicity expected in amphibians and the early-life stages of organisms. In addition, the outbreak of glyphosate-resistant weeds (12 Australia; 32 worldwide) has led to increased use (multiple sprayings per season) of glyphosate, alone or combined with other herbicides. After the controversy arose in 2015, several regulatory authorities, in Australia and worldwide, concluded that glyphosate does not pose a carcinogenic risk to humans at realistic exposure levels.

Recent studies suggest that glyphosate-based herbicides are not as innocuous as expected. Some surfactants used in commercial formulations are more toxic than glyphosate itself. Thus, whole mixtures need to be evaluated to establish their potential risk. Comprehensive studies on the persistence of glyphosate in the environment and the associated chronic long-term effects, at population- and ecosystem-level, are still needed.

Hot Topic Lead Author: 
Name: Natalia Montero
Phone: +34 667102131

Date approved: 
Thursday, May 11, 2017 - 03:05
ID Title Location Type
9085 Australian Pesticides and Veterinary Medicines Authority (2017) Final regulatory position: Consideration of the evidence for a formal reconsideration of glyphosate. Australian Government, 45 pp. Australia, Global Review paper
8998 Adu-Yeboah P., Boutsalis P., Hooper P., Gill G. S. & Preston C. (2014) Use of alternative herbicide mixtures to manage glyphosate-resistant Lolium rigidum Gaud. along crop margins in South Australia. Crop & Pasture Science 65, 1349-1356. South Australia (four sites) Pre-existing contrasts
8999 Amrhein N., Deus B., Gehrke P. & Steinrücken H. C. (1980) The site of inhibition of the shikimate pathway by glyphosate. II. Interference of glyphosate with chorismate formation in vivo and in vitro. Plant Physiology 66, 830-834. Laboratory study Manipulative experiment
9000 Annett R., Habibi H. R. & Hontela A. (2014) Impact of glyphosate and glyphosate-based herbicides on the freshwater environment. Journal of Applied Toxicology 34, 458-479. Global Review paper
9001 ANZECC/ARMCANZ (2000) Australian and New Zealand guidelines for fresh and marine water quality. Australian and New Zealand Environment and Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand, 314 pp. N/A Review paper
9002 Australian Glyphosate Sustainability Working Group (2016) Glyphosate resistant weeds in Australia. (accessed 20/10/2016). NSW, Qld, SA, Vic and WA (Australia) Pre-existing contrast
9003 Bach N. C., Natale G. S., Somoza G. M. & Ronco A. E. (2016) Effect on the growth and development and induction of abnormalities by a glyphosate commercial formulation and its active ingredient during two developmental stages of the South-American Creole f Laboratory study Manipulative experiment
9004 Battaglin W. A., Meyer M. T., Kuivila K. M. & Dietze J. E. (2014) Glyphosate and its degradation product AMPA occur frequently and widely in U.S. soils, surface water, groundwater, and precipitation. Journal of American Water Resources Association 50, 275 U.S. Pre-existing contrasts
9005 Benbrook C. M. (2016) Trends in glyphosate herbicide use in the United States and globally. Environmental Sciences Europe 28:3. US, Global Review paper
9006 Borggaard O. K. & Gimsing A. L. (2008) Fate of glyphosate in soil and the possibility of leaching to ground and surface waters: a review. Pest Management Science 64, 441-456. Global Review paper
9007 Contardo-Jara V., Klingelmann E. & Wiegand C. (2009) Bioaccumulation of glyphosate and its formulation Roundup Ultra in Lumbricus variegatus and its effects on biotransformation and antioxidant enzymes. Environmental Pollution 157, 57-63. Laboratory study Manipulative experiment
9008 Cuhra M., Bøhn T. & Cuhra P. (2016) Glyphosate: too much of a good thing? Frontiers in Environmental Science 4:28. Global Review paper
9009 Cuhra M., Traavik T. & Bøhn T. (2013) Clone-and age-dependent toxicity of a glyphosate commercial formulation and its active ingredient in Daphnia magna. Ecotoxicology 22, 251-262. Laboratory study Manipulative experiment
9010 de Castilhos Ghisi N. & Cestari M. M. (2013) Genotoxic effects of the herbicide Roundup® in the fish Corydoras paleatus (Jenyns 1842) after short-term, environmentally low concentration exposure. Environmental Monitoring and Assessment 185, 3201-3207. Laboratory study Manipulative experiment
9011 Folmar L. C., Sanders H. O. & Julin A. M. (1979) Toxicity of the herbicide glyphosate and several of its formulations to fish and aquatic invertebrates. Archives of Environmental Contamination and Toxicology 8, 269-278. Laboratory study and artificial streams (for reproduction studies) at the U.S. Bureau of Reclamation Field Research Station (Colorado, US). Manipulative experiment
9012 Giesy J. P., Dobson S. & Solomon K. R. (2000) Ecotoxicological risk assessment for Roundup® herbicide. Reviews of Environmental Contamination and Toxicology 167, 35-120. Global Review paper
9013 Guilherme S., Gaivão I., Santos M. A. & Pacheco M. (2010) European eel (Anguilla anguilla) genotoxic and pro-oxidant responses following short-term exposure to Roundup®- a glyphosate-based herbicide. Mutagenesis 25, 523-530. Laboratory study Manipulative experiment
9014 Harayashiki C. A. Y., Varela A. S. Jr., Machado A. A., Cabrera Lda. C., Primel E. G., Bianchini A. & Corcini C. D. (2013) Toxic effects of the herbicide Roundup in the guppy Poecilia vivipara acclimated to fresh water. Aquatic Toxicology 142-143, 176-184. N/A Manipulative experiment
9015 Mensah P. K., Palmer C. G. & Odume O. N. (2015) Chapter 4: Ecotoxicology of glyphosate and glyphosate-based herbicides- Toxicity to wildlife and humans, In: Toxicity and Hazard of Agrochemicals, Larramendi M. (Ed.), InTech, 93-112. Global Review paper
9016 Mercurio P., Flores F., Mueller J. F., Carter S. & Negri A. P. (2014) Glyphosate persistence in seawater. Marine Pollution Bulletin 85, 385-390. Laboratory study Manipulative experiment
9017 Mesnage R., Arno M., Costanzo M., Malatesta M., Séralini G-E. & Antoniou M. N. (2015a) Transcriptome profile analysis reflects rat liver and kidney damage following chronic ultra-low dose Roundup exposure. Environmental Health 14:70. Laboratory study Manipulative experiment
9018 Mesnage R., Defarge N., Spiroux de Vendômois J., Séralini G. E. (2015b) Potential toxic effects of glyphosate and its commercial formulations below regulatory limits. Food and Chemical Toxicology 84, 133-153. Global Review paper
9019 Pérez G. L., Vera M. S. & Miranda L. A. (2011) Chapter 16: Effects of herbicide glyphosate and glyphosate-based formulations on aquatic ecosystems, In: Herbicides and Environment, Kortekamp A. (Ed.), InTech, 343-368. Global Review paper
9020 Puértolas L., Damásio J., Barata C., Soares A. M. V. M. & Prat N. (2010) Evaluation of side-effects of glyphosate mediated control of a giant reed (Arundo Donax) on the structure and fuction of a nearby Mediterranean river ecosystem. Environmental Resea Llobregat River (NE Spain) Manipulative experiment
9021 Relyea R. A. (2005) The impact of insecticides and herbicides on the biodiversity and productivity of aquatic communities. Ecological Applications 15(2), 618-627. N/A Manipulative experiment
9022 Séralini G-E., Clair E., Mesnage R., Gress S., Defarge N., Malatesta M., Hennequin D. & Spiroux de Vendômois J. (2014) Republished study: long-term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize. Environmental Sciences Laboratory study Manipulative experiment
9023 Stachowski-Haberkorn S., Becker B., Marie D., Haberkorn H., Coroller L. & De la Broise D. (2008) Impact of Roundup on the marine microbial community, as shown by an in situ microcosm experiment. Aquatic Toxicology 89, 232-241. Laboratory study Manipulative experiment
9024 Uren Webster T. M. U. & Santos E. M. (2015) Global transcriptomic profiling demonstrates induction of oxidative stress and of compensatory cellular stress responses in brown trout exposed to glyphosate and Roundup. BMC Genomics 16:32. Laboratory study Manipulative experiment

Further information about this topic contact:

Natalia Montero
+34 667102131

Chair, Hot Topics Editorial Board
Dr Rachel Standish