See also Food and Farm Discussion Lab links on Glyphosate.
- Glyphosate is a broad-spectrum systemic herbicide and crop desiccant. It is an organophosphorus compound, specifically a phosphonate. It is used to kill weeds, especially annual broadleaf weeds and grasses that compete with crops. It was discovered to be an herbicide by Monsanto chemist John E. Franz in 1970. Monsanto brought it to market in 1974 under the trade name Roundup, and Monsanto's last commercially relevant United States patent expired in 2000.
- 1 soil microbes
- 2 drying
- 3 safety
- 4 IARC
- 5 urine
- 6 breast milk
- 7 Snopes
- 8 comparison with toxicity of other herbicides
- 9 aquatic use
Non-Target Effects of Glyphosate on Soil Microbes Matt D. Busse, Alice W. Ratcliff, Carol J. Shestak, Robert F. Powers : Pacific Southwest Research Station, USDA Forest Service, Redding, CA; 2000 Proceedings of the California Weed Science Society (Volume 52)
- Glyphosate is among the most popular herbicides registered for forest use in California. Noted for its broad effectiveness on competing vegetation, mild effect on conifers, rapid inactivation in soil, and low mammalian toxicity (DiTomaso 1997), glyphosate is an integral component of conifer release programs and has led to improvements in the growth of intensively managed forests (Powers and Reynolds 1999). Benefits of herbicide use must be viewed cautiously, however. Public concerns about environmental risks makes their forestry use controversial. Policy makers and forest managers thus need scientific documentation of the ecological effects of herbicides that go beyond the toxicological requirements met during product registration. In particular, our knowledge of the effect of glyphosate on non-target organisms in forest ecosystems is incomplete.
Why Is Glyphosate Sprayed on Crops Right Before Harvest? Ken Roseboro; EcoWatch; 5 Mar 2016
- Glyphosate, the main ingredient in Monsanto’s Roundup herbicide, is recognized as the world’s most widely used weed killer. What is not so well known is that farmers also use glyphosate on crops such as wheat, oats, edible beans and other crops right before harvest, raising concerns that the herbicide could get into food products. Glyphosate has come under increased scrutiny in the past year. Last year the World Health Organization’s cancer group, the International Agency for Research on Cancer, classified it as a probable carcinogen. The state of California has also moved to classify the herbicide as a probable carcinogen. A growing body of research is documenting health concerns of glyphosate as an endocrine disruptor and that it kills beneficial gut bacteria, damages the DNA in human embryonic, placental and umbilical cord cells and is linked to birth defects and reproductive problems in laboratory animals.
The Truth About Glyphosate and Wheat Sarah Schultz; 16 Nov 2014
- One of the practices that is highly misunderstood is the application of glyphosate for pre-harvesting wheat. In layman’s terms, this simply means spraying our mature wheat crop with glyphosate before it’s ready to be harvested. Though glyphosate is not a true desiccant (a desiccant is applied for rapid dry down & early harvest), it is generally used for weed control and can aid in dry down of crops, but the effects take much longer. This is done with care, precise timing, it is backed by science and it is regulated and monitored.
- Claim: U.S. farmers are saturating wheat crops with Roundup herbicide as a desiccant before each harvest, causing an increase in wheat-related ailments.
- Verdict: Mixture
Concerns over use of glyphosate-based herbicides and risks associated with exposures: a consensus statement John Peterson Myers, Michael N. Antoniou, Bruce Blumberg, Lynn Carroll, Theo Colborn, Lorne G. Everett, Michael Hansen, Philip J. Landrigan, Bruce P. Lanphear, Robin Mesnage, Laura N. Vandenberg, Frederick S. vom Saal, Wade V. Welshons and Charles M. Benbrook; Environmental Health17 Feb 2016
- This Statement of Concern is directed to scientists, physicians, and regulatory officials around the world. We highlight changes in the scope and magnitude of risks to humans and the environment stemming from applications of glyphosate-based herbicides (GBHs). The objectives of this statement are to: 1) demonstrate the need for better monitoring of GBH residues in water, food, and humans; (2) identify limitations or weaknesses in the way the EPA, the German Federal Institute for Risk Assessment, and others have previously assessed the potential risks to humans from exposure to GBHs; and (3) provide recommendations on data needs and ways to structure future studies addressing potential health risks arising from GBH exposures.
- Our focus is on the unanticipated effects arising from the worldwide increase in use of GBHs, coupled with recent discoveries about the toxicity and human health risks stemming from use of GBHs. Our concern deepened when the World Health Organization’s International Agency for Research on Cancer (IARC) re-classified glyphosate as “probably carcinogenic to humans” (i.e., Group 2A) .
- We highlight a number of issues that influence our concern about GBHs including: 1) increased use of GBHs over the past decade, including new uses for these herbicides just prior to harvest that can lead to high dietary exposures; 2) detection of glyphosate and its metabolites in foods; 3) recent studies that reveal possible endocrine system-mediated and developmental impacts of GBH exposures; and 4) additional complications for farmers, most acutely the emergence and spread of weeds resistant to glyphosate and the concomitant use of multiple herbicides in mixtures, both of which increase the risk of human and environmental harm. We discuss evidence pointing to the need to adjust downward the acceptable daily intake for glyphosate. Our major concerns are embodied in a series of consensus points that explicitly address the strength of the supporting evidence, and our recommendations focus on research essential in narrowing uncertainty in future GBH risk assessments.
Glyphosate poisoning Bradberry SM1, Proudfoot AT, Vale JA.; Toxicological Reviews; 2004
- "There is insufficient evidence to conclude that glyphosate preparations containing POEA are more toxic than those containing alternative surfactants. Although surfactants probably contribute to the acute toxicity of glyphosate formulations, the weight of evidence is against surfactants potentiating the toxicity of glyphosate. Accidental ingestion of glyphosate formulations is generally associated with only mild, transient, gastrointestinal features. Most reported cases have followed the deliberate ingestion of the concentrated formulation of Roundup (The use of trade names is for product identification purposes only and does not imply endorsement.) (41% glyphosate as the IPA salt and 15% POEA). There is a reasonable correlation between the amount ingested and the likelihood of serious systemic sequelae or death. Advancing age is also associated with a less favourable prognosis. Ingestion of >85 mL of the concentrated formulation is likely to cause significant toxicity in adults. "
Glyphosate - general fact sheet National Pesticide Information Center
- What is glyphosate?
- What are some products that contain glyphosate?
- How does glyphosate work?
- How might I be exposed to glyphosate?
- What are some signs and symptoms from a brief exposure to glyphosate?
- What happens to glyphosate when it enters the body?
- Is glyphosate likely to contribute to the development of cancer?
- Has anyone studied non-cancer effects from long-term exposure to glyphosate?
- Are children more sensitive to glyphosate than adults?
- What happens to glyphosate in the environment?
- Can glyphosate affect birds, fish, and other wildlife?
Carcinogenicity of tetrachlorvinphos, parathion, malathion, diazinon, and glyphosate Kathryn Z Guyton, Dana Loomis, Yann Grosse, Fatiha El Ghissassi, Lamia Benbrahim-Tallaa, Neela Guha, Chiara Scoccianti, Heidi Mattock, Kurt Straif, on behalf of the International Agency for Research on Cancer Monograph Working Group, IARC, Lyon, France; The Lancet; 20 Mar 2015
- In March, 2015, 17 experts from 11 countries met at the International Agency for Research on Cancer (IARC; Lyon, France) to assess the carcinogenicity of the organophosphate pesticides tetrachlorvinphos, parathion, malathion, diazinon, and glyphosate (table). These assessments will be published as volume 112 of the IARC Monographs.
Glyphosate IARC monographs
Conclusion on the peer review of the pesticide risk assessment of the active substance glyphosate European Food Safety Authority; 12 Nov 2015
- The conclusions of the European Food Safety Authority (EFSA), following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State Germany, for the pesticide active substance glyphosate are reported. The context of the peer review was that required by Commission Regulation (EU) No 1141/2010 as amended by Commission Implementing Regulation (EU) No 380/2013. The conclusions were reached on the basis of the evaluation of the representative uses of glyphosate as a herbicide on emerged annual, perennial and biennial weeds in all crops [crops including but not restricted to root and tuber vegetables, bulb vegetables, stem vegetables, field vegetables (fruiting vegetables, brassica vegetables, leaf vegetables and fresh herbs, legume vegetables), pulses, oil seeds, potatoes, cereals, and sugar- and fodder beet; orchard crops and vine, before planting fruit crops, ornamentals, trees, nursery plants etc.] and foliar spraying for desiccation in cereals and oilseeds (pre-harvest). The reliable endpoints, concluded as being appropriate for use in regulatory risk assessment and derived from the available studies and literature in the dossier peer reviewed, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified. Following a second mandate from the European Commission to consider the findings from the International Agency for Research on Cancer (IARC) regarding the potential carcinogenicity of glyphosate or glyphosate-containing plant protection products in the on-going peer review of the active substance, EFSA concluded that glyphosate is unlikely to pose a carcinogenic hazard to humans and the evidence does not support classification with regard to its carcinogenic potential according to Regulation (EC) No 1272/2008.
expert reaction to carcinogenicity classification of five pesticides by the International Agency for Research on Cancer (IARC) Science Media Centre; 20 Mar 2015
So Roundup “probably” causes cancer. This means what, exactly? Nathanael Johnson; Grist; 24 Mar 2015
- Here are the takeaways:
- There is a real chance that these pesticides could cause cancer, and we should be careful with them.
- There’s controversy — several scientists disagreed with the designation.
- Don’t forget that the list of things that probably cause cancer includes … just about everything.
- That last point is worth dwelling on a bit. Here’s the WHO’s full list of “known” (group 1), “probable” (group 2A), and “possible” (group 2B) carcinogens. It’s a weird list. Sunshine, alcoholic beverages (the ethanol therein), wood dust, and outdoor pollution are “known” carcinogens. The “probable” group includes wood smoke, night shifts (they disrupt circadian rhythms), and hot mate (the South American drink).
No, Roundup does not cause cancer James Cooper; Examiner; 28 Apr 2016
- The scientific world was astonished (to put it mildly) when the IARC (International Agency for Research on Cancer), a sub-unit of the WHO declared that Roundup (glyphosate) probably causes cancer, putting an herbicide that has been in use for over 40 years into their Group 2A. Their report was published initially as a summary in The Lancet, and then as a complete IARC monograph.
GLYPHOSATE: Report of the Cancer Assessment Review Committee UNITED STATES ENVIRONMENT AL PROTECTION AGENCY; 1 Oct 2015
- In accordance with the 2005 Guidelines for Carcinogen Risk Assessment, based on the weight-ofevidence, glyphosate is classified as “Not Likely to be Carcinogenic to Humans”.
Glyphosate: What's the lowdown? Sense About Science;
Notes From The Glyphosate Dust Up Marc Brazeau; Food and Farm Discussion Lab; 4 May 2015
- I don’t have much to add to the recent dustup over the WHO’s International Agency for Research on Cancer (IARC) designating that glyphosate is a probable carcinogen, but I’d like to highlight some of the most useful coverage.
- “What the IARC performs is hazard assessment,” says Aaron Blair, who chaired the group of scientists that prepared the IARC’s assessment of glyphosate. Blair is a scientist emeritus at the National Cancer Institute. Hazard assessment, he explains, is concerned with a simple question: Could a substance cause damage “in some circumstance, at some level of exposure?” How commonly such circumstances or exposures actually occur in the real world, he says, is an entirely different question, and not one that IARC tries to answer.
- In other words, the IARC is saying that glyphosate probably could cause cancer in humans, but not that it probably does.
Does glyphosate cause cancer? Iida Ruishalme; Thoughtscapism; 7 Sep 2016
- Much media and public attention on glyphosate followed after World Health Organisations subgroup, International Agency for Research on Cancer (IARC) declared that according to their classification, glyphosate falls under substances 2a – “probably carcinogenic”. What the media attention often failed to report is that IARC does not actually look at risk – how big is the risk for said carcinogenic effects? What levels are safe and what aren’t?
IARC Under Fire from Scientists: Mission Outdated, Methods Lacking Iida Ruishalme; Thoughtscapism; 6 Nov 2016
- Considering recently published scientific reviews on the International Agency on Cancer Research (IARC) concerning their methods and overall mission, as well as their specific conclusion on glyphosate, I thought the topic deserved an update of its own.
Toxicologist pans UN glyphosate report Robert Arnason; The Western Producer; 27 Mar 2015
- In a brief statement explaining the new designation, the scientists cited a number of research papers, such as a study on rural Colombians who were exposed to a spray of Roundup. IARC said the study demonstrated that glyphosate can cause genotoxicity, or DNA damage, and cause cellular mutations that may result in cancer. Keith Solomon, a University of Guelph professor emeritus and a globally recognized authority on pesticides, said the conclusion is “totally wrong.” Solomon should know because he wrote the Colombian study.
Differences in the carcinogenic evaluation of glyphosate between the International Agency for Research on Cancer (IARC) and the European Food Safety Authority (EFSA) Christopher J Portier & others; J Epidemiol Community Health doi:10.1136/jech-2015-207005;
- The International Agency for Research on Cancer (IARC) Monographs Programme identifies chemicals, drugs, mixtures, occupational exposures, lifestyles and personal habits, and physical and biological agents that cause cancer in humans and has evaluated about 1000 agents since 1971. Monographs are written by ad hoc Working Groups (WGs) of international scientific experts over a period of about 12 months ending in an eight-day meeting. The WG evaluates all of the publicly available scientific information on each substance and, through a transparent and rigorous process,1 decides on the degree to which the scientific evidence supports that substance's potential to cause or not cause cancer in humans.
- For Monograph 112,2 17 expert scientists evaluated the carcinogenic hazard for four insecticides and the herbicide glyphosate.3 The WG concluded that the data for glyphosate meet the criteria for classification as a probable human carcinogen.
- The European Food Safety Authority (EFSA) is the primary agency of the European Union for risk assessments regarding food safety. In October 2015, EFSA reported4 on their evaluation of the Renewal Assessment Report5 (RAR) for glyphosate that was prepared by the Rapporteur Member State, the German Federal Institute for Risk Assessment (BfR). EFSA concluded that ‘glyphosate is unlikely to pose a carcinogenic hazard to humans and the evidence does not support classification with regard to its carcinogenic potential’. Addendum 1 (the BfR Addendum) of the RAR5 discusses the scientific rationale for differing from the IARC WG conclusion.
- Serious flaws in the scientific evaluation in the RAR incorrectly characterise the potential for a carcinogenic hazard from exposure to glyphosate. Since the RAR is the basis for the European Food Safety Agency (EFSA) conclusion,4 it is critical that these shortcomings are corrected.
IARC-Gate? Are Europe’s anti-chemical enviros conspiring to suppress conflict-of-interest scandal? David Zaruk & Jon Entine; Genetic Literacy Project; 7 Apr 2016
IARC’s unprofessional and unethical behaviour. Time to retract their glyphosate monograph RISKMONGER; 13 Apr 2016
- Christopher Portier was employed by the anti-pesticide American NGO, Environmental Defense Fund (EDF).
- In 2014 Portier chaired the IARC expert advisory committee on priorities for the coming years (including glyphosate). IARC did not declare his employment with the activist NGO EDF.
- In 2015, Portier served as the only external representative on the IARC glyphosate team with the role of technical adviser, even though he was working for an anti-pesticides NGO, had published many articles against Monsanto and was not even a toxicologist.
- The IARC study rejected thousands of documents on glyphosate that had industry involvement and based their decision on carcinogenicity on the basis of eight studies (rejecting a further six because they did not like their conclusions).
Monsanto Stunned – California Confirms ‘Roundup’ Will Be Labeled “Cancer Causing” EDITOR; The Event Chronicle; 23 Feb 2016
- Sacramento, CA — California just dealt Monsanto a blow as the state’s Environmental Protection Agency will now list glyphosate — the toxic main ingredient in the U.S.’ best-selling weedkiller, Roundup — as known to cause cancer. Under the Safe Drinking Water and Toxic Enforcement Act of 1986 — usually referred to as Proposition 65, its original name — chemicals that cause cancer, birth defects, or other reproductive harm are required to be listed and published by the state. Chemicals also end up on the list if found to be carcinogenic by the International Agency for Research on Cancer (IARC) — a branch of the World Health Organization.
Proposed Re-evaluation Decision PRVD2015-01, Glyphosate Health Canada; 17 Jun 2015
- An evaluation of available scientific information found that products containing glyphosate do not present unacceptable risks to human health or the environment when used according to the proposed label directions.
The BfR has finalised its draft report for the re-evaluation of glyphosate Bundesinstitut für Risikobewertung (BfR)
- In conclusion of this re-evaluation process of the active substance glyphosate by BfR the available data do not show carcinogenic or mutagenic properties of glyphosate nor that glyphosate is toxic to fertility, reproduction or embryonal/fetal development in laboratory animals.
Cancer all-clear given to weedkiller glyphosate by New Zealand scientific review GERARD HUTCHING; New Zealand Farmer; 12 Aug 2016
- New Zealand scientists have reviewed the evidence on the weedkiller glyphosate and announced it is "unlikely" to be carcinogenic and should not be classified as a mutagen or carcinogen under the HSNO Act. Poisons expert Dr Wayne Temple and his colleague from the National Poisons Centre, Michael Beasley, carried out the review, which was commissioned by the Environmental Protection Authority (EPA).
Review of the Evidence Relating to Glyphosate and Carcinogenicity Wayne Temple; Environmental Protection Authority; Aug 2016
- This report discusses the relevant data on glyphosate, especially the more recent studies, and reviews the basis on which the IWG classified it as a probable human carcinogen (Group 2A). This involves review of the quality of evidence for carcinogenicity in humans and experimental animals and the mechanistic arguments.
U.N. experts find weed killer glyphosate unlikely to cause cancer Kate Kelland; Reuters; 16 May 2016
- The pesticide glyphosate, sold by Monsanto in its Roundup weed killer product and widely used in agriculture and by gardeners, is unlikely to cause cancer in people, according to a new safety review by United Nations health, agriculture and food experts. In a statement likely to intensify a row over its potential health impact, experts from the U.N.'s Food and Agriculture Organization (FAO) and World Health Organization (WHO) said glyphosate is "unlikely to pose a carcinogenic risk to humans" exposed to it through food. It is mostly used on crops.
Contradicting IARC, World Health Organization says glyphosate unlikely to cause cancer Kate Kelland; Reuters; 17 May 2016
Why regulators conclude glyphosate safe while IARC, alone, claims it could cause cancer? Andrew Porterfield; Genetic Literacy Project; 24 Jul 2015
Results of Glyphosate Pee Test Are in ‘And It’s Not Good News’ Lorraine Chow; EcoWatch; 12 May 2016
- Last month, Members of the European Parliament (MEPs) volunteered to take a urine test to see if glyphosate—the cancer-linked weedkiller—is in their system. Forty-eight MEPs from 13 different European Union countries participated in the test, and now the results are in.
A critical review of glyphosate findings in human urine samples and comparison with the exposure of operators and consumers Lars Niemann, Christian Sieke, Rudolf Pfeil, Roland Solecki; Journal für Verbraucherschutz und Lebensmittelsicherheit; 8 Jan 2015
- For example: If a urinary concentration of 6 µg glyphosate/L would have been measured, a daily excretion of 12 µg can be assumed. For a 60 kg weighing person, an internal dose of 0.2 µg/kg bw would result. If exposure of this person can be reasonably assumed as mainly occupational or residential, i.e., occurring predominantly by the dermal and inhalative routes, this dose of 0.0002 mg/kg bw might be directly compared to the AOEL and would account for only 0.2 % of this reference dose.
- If dietary exposure is considered the more likely route of glyphosate intake, a 20 % oral absorption must be taken into account ... Therefore, an internal dose of 12 µg would be expected to result from a totally ingested amount of 60 µg, equivalent to an “external dose” of 1 µg/kg bw. This dose of 0.001 mg/kg bw would account for 0.2 % of the ADI that is, in this case, the more appropriate reference dose to compare with.
McGuire et al
Glyphosate and aminomethylphosphonic acid are not detectable in human milk Michelle K McGuire, Mark A McGuire, William J Price, Bahman Shafii, Janae M Carrothers, Kimberly A Lackey, Daniel A Goldstein, Pamela K Jensen, and John L Vicini; The American Journal of Clinical Nutrition; 30 Mar 2016
U.S. breast milk is glyphosate free Science Daily; 23 Jul 2015
- Study is first independently verified look for the presence of Roundup ingredient in human milk
Moms Across America
Glyphosate Testing Full Report: Findings in American Mothers’ Breast Milk, Urine and Water Zen Honeycutt - Moms Across America, Henry Rowlands - Sustainable Pulse; Moms Across America; 7 Apr 2014 (pdf)
- In the first ever testing on glyphosate herbicide in the breast milk of American women, Moms Across America and Sustainable Pulse have found ‘high’ levels in 3 out of the 10 samples tested. The shocking results point to glyphosate levels building up in women’s bodies over a period of time, which has until now been refuted by both global regulatory authorities and the biotech industry.
Debunking pseudo science “lab testing” health risk claims about glyphosate (Roundup) Academics Review; 10 Apr 2014
Willingham commentary on McGuire and MAA
Monsanto-Linked Study Finds No Monsanto-Linked Herbicide Glyphosate In Breast Milk Emily Willingham; Forbes, 4 Apr 2016
- The herbicide glyphosate does not show up in breast milk, according to findings from a study published in the American Journal of Clinical Nutrition. The study, however, is weighted with conflicts of interest that include having three Monsanto employees as authors. The first two authors also have received grants from Monsanto, and the costs of the chemical analyses for the study were covered by Monsanto. This study is not, however, the only one reporting this outcome.
Monsanto, Monsanto, blah blah breast milk, Monsanto Bill Price; BioFortified blog; Apr 2016
- Complaint about Willingham's article by a McGuire co-author
ConfoundUp Alex Kasprak; Snopes; 16 Nov 2016
- A laboratory test performed by food activists is going viral, but its results and the allegations drawn from them are not reliable.
Snopes Claims About Glyphosate in Food Kevin Folta; blog; 17 Nov 2016
- I like Snopes. So many times I've been rescued from a critical debunking excursion because someone had provided excellent analysis that I could use as a starting point. It is really disappointing to see them go soft and conflate unrelated issues that just confuse the reader. The article about the Food Babe's claims about Monsanto covering up glyphosate in food items seemed like it would follow the science and once again foist her on her own critically underpowered petard. But instead the article by Alex Kasprak just creates confusion. Even the subhead says, "Monsanto suppressing evidence of cancerous herbicide in food?"
comparison with toxicity of other herbicides
Herbicides: How Toxic Are They? Fred Fishel, Jason Ferrell, Greg MacDonald, Brent Sellers; University of Florida IFAS Extension;
- Comparison of Paraquat, Caffeine, Bleach, Pendimethalin (Prowl), Tylenol, Atrazine, Household ammonia (10%), Glyphosate (Roundup), Codeine, Table salt etc
About those harsher herbicides that glyphosate helped replace CREDIBLE HULK; 2 Jun 2015
- One of the common criticisms of commercially available Genetically Engineered (GE) seeds is the idea that they have led to an increase in pesticide use. In actuality, it turns out that they’ve corresponded to a decrease in total pesticide use, but this is attributable primarily to insect resistant GE crops, and critics argue that herbicide resistant crops have led to an increase in herbicide usage. It is true that the rise in popularity of glyphosate-resistant (GR) crops in particular has coincided with an increase in the use of glyphosate, which had already been in use to some degree for a couple of decades before the implementation of glyphosate-resistant crops. However, what critics invariably fail to mention is that its rise in popularity also coincided with the phasing out of other herbicides, most of which were significantly more toxic than glyphosate (about which I’ve written in detail here). The purpose of this article is not to claim that glyphosate and GR crops are the be all end all of weed control (they’re not), nor is it to claim that they were causally responsible for any and every desirable change we see in herbicide usages patterns. Rather, the purpose of this is to show that when opponents of GE technology and of glyphosate claim that GR crops are bad on the grounds that they increased glyphosate use, they are leaving out critical information that would be highly inconvenient for their narrative.
Glyphosate on digestive enzymes activity in piava (Leporinus obtusidens) Joseânia Salbego, Alexandra Pretto, Vera Maria Machado da Silva, Vania Lucia Loro, Rafael Lazzari, Carolina Rosa Gioda, Bernardo Baldisserotto; Ciência Rural; Sep 2014
- The effects of glyphosate, a nonselective herbicide (1.0 or 5.0mg L-1) on digestive enzymes activity (stomach and intestine) were evaluated in juveniles of piava (Leporinus obtusidens) after 90 days of exposure. The activity of acid protease, trypsin, chymotrypsin and amylase increased with the increase of glyphosate concentration. These results indicate that glyphosate affects digestive enzyme activities in this species, and may be an indicator of poor nutrient availability when fish survive in herbicide-contaminated water.
discussion Food and Farm Discussion Lab; facebook, Jul 2016