Glyphosate, the active ingredient in Roundup, is one of the most commonly used herbicides in New Zealand. Recently, a court in America awarded $289 million in damages to a man who claimed workplace exposure to glyphosate caused his cancer. What does this ruling mean for New Zealand?
In August this year a California superior court jury awarded Dewayne Lee Johnson more than $289 million in damages from Monsanto Corporation. Johnson, a former groundskeeper, sued Monsanto, claiming work place exposure to glyphosate, the active ingredient in Roundup, caused his non-Hodgkin lymphoma (NHL), a type of cancer.
Glyphosate has been approved for use in New Zealand since 1976. It acts by inhibiting an enzyme specific to plants so that they die. Glyphosate is used mostly in weed control in agricultural production, and in amenity situations including home gardens.
Conventional cropping and pasture renovation systems also frequently depend on glyphosate to control vegetation pre-cultivation and/or to treat persistent weeds after crop removal. Vineyard and orchard tree lines and other perennial crops are commonly repetitively treated solely with glyphosate to manage weeds.
Over 500,000 hectares of land in New Zealand is now under reduced cultivation and direct drilling. These practices are heavily dependent on the repeated use of glyphosate. There are no figures for the exact amount of glyphosate used in New Zealand, but there are 94 trade name products registered containing the ingredient.
Globally, usage of glyphosate has significantly increased since 1994, now totalling about 800,000 tonnes annually. About 40% of this product is made in China.
The increase is mostly from the adoption of Genetically Modified crops, such as Round Up ready soy bean, corn and cotton in USA, and South America where glyphosate is used for weed control across the whole crop. Increases also come from the steady expansion in the number of crops registered for use on glyphosate product labels, the adoption of no-tillage and conservation tillage systems, the declining price per pound of active ingredient, new application method and timing options, and new agricultural use patterns (e.g. as a desiccant to accelerate the harvest of small grains, edible beans, and other crops).
What do we know of the health effects of glyphosate?
There have been a number of heavy hitting governmental reports over recent years – with varying agreement.
Differences between studies depended on whether they:
- Looked at dietary or occupational exposure
- Considered glyphosate alone or in other formulations
- Gave more weighting to higher quality studies than case studies.
All but one concluded that glyphosate is unlikely to pose a carcinogenic risk to humans. We have summarised them below.
Agency | Date | Substance(s) evaluated | Findings | Comment |
WHO International Agency for Research on Cancer | March 2015 | Glyphosate as an active substance – and glyphosate-based co-formulations | “..probably carcinogenic in humans” (category 2A) The cancer site was specific to non Hodgkins Lymphoma (NHL). | Looked at occupational or environmental exposure, reviewed epidemiological studies, animal studies, and in vitro studies. |
European Food Safety Authority | Nov 2015 | Glyphosate only | Unlikely to be genotoxic (i.e. damaging to DNA) or to pose a carcinogenic threat to humans. Studies that look solely at the active substance glyphosate do not show this effect.
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Looked at dietary exposure and risk.
An acceptable daily intake (ADI) for consumers has been set at 0.5 mg/kg body weight per day.
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WHO and FAO Joint committee on pesticide residues | 2016 | Glyphosate as an active substance – and glyphosate-based co-formulations | Glyphosate is unlikely to pose a carcinogenic risk to humans from exposure through the diet.
It remains less clear what the situation is with occupational exposure. |
Human dietary exposure and risk
and giving admissible daily maximum intake limits of 0-1 milligram/kg of body weight per day. |
European Chemicals Agency (ECHA) Committee for Risk Assessment (RAC) | 2017 | RAC assessed glyphosate’s hazardousness against the criteria in the Classification, Labelling and Packaging Regulation | Causes serious eye damage and toxic to aquatic life, but did not find evidence implicating it as a carcinogen, a mutagen, toxic to reproduction, nor toxic to specific organs.[17] | RAC provides an independent scientific opinion on the hazard classification of the substance. The classification is based solely on the hazardous properties of the substance. It does not take into account the likelihood of exposure to the substance and therefore does not address the risks of exposure. |
New Zealand’s Environmental Protection Authority (EPA) | Aug 2016 | EPA concluded that glyphosate was unlikely to cause cancer in humans. | Based on a weight of evidence approach, taking into account the quality and reliability of the available data, it does not require classification under HSNO as a carcinogen or mutagen. |
In New Zealand, the presence of glyphosate in food is controlled through the use of maximum residue levels (MRLs), set by the Ministry for Primary Industries. Glyphosate in agricultural products must be at less than 0.01mg/kg for fruit with a default level of 0.1 mg/kg for other food products.
Consequences for agriculture
Notwithstanding the above governmental reports on the health effects of glyphosate, in 2017 the European Parliament voted by 355-204 to oppose the renewal in 2018 of the registration of glyphosate for households and in 2022 for agriculture.
But weeds are a legitimate problem in farming that have to be dealt with one way or another. Farmers, policymakers and activists have begun the search for viable alternatives to the agricultural chemical. It’s hard to find the combination of right price, effectiveness and absence of harm or persistence. Glyphosate enabled the revolutionary step to non-plough tillage — which saves time, protects groundwater, avoids soil erosion and reduces the release of soil carbon.
What next?
Bayer, the new owner of Monsanto, asked a state court to set aside the recent August 2018 decision, but last week failed to persuade the judge. The damages were lowered though to $78.6 million.
Following that lawsuit, General Mills was also sued by a plaintiff claiming the company failed to disclose that glyphosate was in its popular Cheerios cereal. And the cases don’t stop there — not even close. There are now about 8700 claims against Monsanto pending in federal and state courts across the United States. The ruling will allow California to proceed with the process of listing glyphosate, the active ingredient in Roundup, as a chemical “known to the state to cause cancer”.
The terms of the US case were interesting as the plaintiff didn’t need to conclusively demonstrate that glyphosate caused the cancer – only that it was a plausible contributing factor.
Our point of view
It’s a balance of risks and benefits.
Glyphosate is a very useful herbicide that has enabled cheap food production, and also the recent development of no tillage systems, which have environmental benefits.
The weight of independently assessed effects on humans indicates a high safety level not shared by many other agrichemicals.
But it’s unfortunate that agriculture has not always used this good chemical carefully and sparingly. The tide of public opinion is turning against its continued usage and that’s a hard tide to fight long term, even for Monsanto and its new owner, Bayer.