The round up on glyphosate

By Gabrielle Stannus

Glyphosate is an active ingredient found in a number of commercial and domestic herbicides used commercially and domestically to manage weeds. Glyphosate is a non-selective, broad-spectrum, post-emergent systemic herbicide effective on a range of annual and perennial plants. It must be applied to actively growing plants to work as it is translocated throughout the plant, inhibiting the enzymes involved in the synthesis of the aromatic amino acids: tyrosine, tryptophan and phenylananine, and halts the production of plant proteins1. There are over 500 products with glyphosate listed as the active constituent registered for use with the Australian Pesticides and Veterinary Medicines Authority (APVMA), including Roundup®2.

In August, a jury awarded Californian groundskeeper Dewayne Johnson $289 million in a lawsuit against Monsanto on the grounds that his terminal cancer was caused by unsafe exposure to that company’s glyphosate-based herbicides (GBH)3. The jury found that Monsanto failed to adequately warn of the danger or instruct on the safe use of Roundup® and RangerPro®, and that the lack of sufficient warning was a substantial factor in causing harm to Johnson.

Throughout the August trial, both the plaintiff and the defendant produced expert scientific testimony about the science behind GBH. Baum Hedlund Aristei & Goldman, consumer attorneys representing Johnson, collected documentary evidence to support their client’s claim. These so-called “ Monsanto Papers” were featured prominently in a recent episode of ABC TV’s Four Corners program, and made reference to the International Agency for Research on Cancer’s (IARC) ‘Glyphosate Monograph’.

In 2015, IARC, the World Health Organisation’s specialised cancer agency, classified glyphosate as a Group 2A agent as they evaluated it as "probably carcinogenic to humans"4. This study looked at both real-world formulations and applications of glyphosate, and of glyphosate itself in laboratory testing. GBHs commonly contain surfactants to promote absorption, the presence of which may have synergistic effects. In IARC’s words:

“Group 2A means that the agent is probably carcinogenic to humans. This category is used when there is limited evidence of carcinogenicity in humans and sufficient evidence of carcinogenicity in experimental animals. Limited evidence means that a positive association has been observed between exposure to the agent and cancer but that other explanations for the observations (called chance, bias, or confounding) could not be ruled out. This category is also used when there is limited evidence of carcinogenicity in humans and strong data on how the agent causes cancer”5.

However, following the IARC’s determination, the Australian Pesticides and Veterinary Medicines Authority (APVMA) itself considered glyphosate and found no grounds to place it under formal reconsideration5. APVMA advises that GBHs remain registered for use in Australia and APVMA approved products containing glyphosate can continue to be used safely according to label directions. The APVMA reminds users of any agricultural and veterinary chemicals to read the label and follow the safety and use instructions carefully. That way users will not only minimise the risk of their exposure to glyphosate, but also maximise that product’s effectiveness.

In line with the APVMA directive, NGIA’s advice to all users of any GBH as well as any herbicide, fungicide or pesticide product is to continue to:

•Always follow the application and safety instructions on the label and Material Safety Datasheet (MSD)
•Contact the product manufacturer for more information
•Ensure that only persons which have received appropriate and adequate training prepare and apply agrochemicals
•Apply IPM principles to pest and weed management

PS. This week the trial judge in ‘Dewayne Johnson vs. Monsanto Company’ significantly reduced the amount of punitive damages that Johnson will receive, whilst still upholding the original verdict7.

Further reading
Safety and use of glyphosate:
1. Heilig, G 2012, 'Killing weeds in the garden with glyphosate', Michigan State University Extension, viewed 25 October 2018,
2. Australian Pesticides and Veterinary Medicines Authority (APVMA) 2018, Public Chemical Registration Information System Search, viewed 24 October 2018,
3. Superior Court of the State of California for the State of San Francisco 2018, Case No. CGC-16-550128 Verdict Form, Filed 10 August 2018, viewed 24 October 2018,
4. International Agency for Research on Cancer (IARC) 2015, Glyphosate, IARC Monographs, Vol. 112, Iss. 10, viewed 25 October 2018,
5. International Agency for Research on Cancer (IARC) 2015, IARC Monographs Volume 112: evaluation of five organophosphate insecticides and herbicides, 20 March 2015, viewed 25 October 2018, (page 2)
6. APVMA 2018, ‘Glyphosate’, viewed 25 October 2018,
7. Superior Court of the State of California for the State of San Francisco 2018, Case No. CGC-16-550128 Order denying Monsanto Company's motion for judgment notwithstanding the verdict and conditionally denying Monsanto's motion for new trial, Filed 22 October 2018, viewed 25 October 2018,