A new scientific analysis of the cancer-causing propensities of the herbicide glyphosate, which is the most widely used weedkiller on Earth, has determined that people with high exposure have a 41% higher risk of developing non-Hodgkin lymphoma. (theguardian.com).
The scientific evidence shows a strong and compelling link between high exposure to the herbicide and a higher risk of NHL, according to the study authors. However, they did note the exact risk numbers should be carefully interpreted.
These findings by five American scientists directly contradict the EPA’s many assurances of safety of the Roundup weed killer that contains glyphosate. The announcement comes as several international regulators have been considering limiting the use of these weed killers in farming.
At this time, Monsanto and the German owner Bayer AG are facing at least 9,000 Roundup cancer lawsuits in the United States by people who have been exposed to glyphosate and have NHL. They blame Monsanto for their diseases. The first plaintiff won a unanimous verdict against Monsanto last year, which the company is appealing. That case involved a San Francisco school grounds keeper who was awarded $289 million by the jury. The next trial with another plaintiff is on Feb. 25. Several more glyphosate trials are set for 2019 and 2020.
Monsanto argues there is no strong scientific link that shows an association between NHL and glyphosate exposure. Company officials note that the findings by EPA that the chemical is not likely to lead to cancer is also backed by hundreds of studies that have not seen such a connection.
Monsanto claims the scientists for the International Agency for Research on Cancer or IARC who classified the chemical as a possible human carcinogen in 2015 engaged in inappropriate conduct and did not give enough weight to several vital studies.
New Evidence Against Monsanto
But this new scientific evidence could make it harder for Monsanto defend its top selling herbicide. Three of the study authors were chosen by EPA as key board members for a scientific advisory panel on glyphosate in 2016. The new paper was first published by the journal Mutation Research and Reviews in Mutation Research. The editor in chief of that journal is EPA scientist David DeMarini.
According to the study’s authors, the meta analysis used is different from other assessments in the past. The paper makes a strong case than earlier work that there is strong evidence of high risk of NHL because of glyphosate exposure. From a population health point of view there are serious concerns over cancer risks, states co-author Lianne Sheppard.
Sheppard was one of the advisers to EPA on the chemical glyphosate and was among some advisors who informed the EPA that it did not follow appropriate scientific protocols to determine that glyphosate is unlikely to cause cancer. She said that it was wrong how the EPA did the assessment. It was obvious, she said, that they failed to follow their own rules. She believes there is substantial evidence that glyphosate is carcinogenic.
According to an EPA spokesman, they are looking over the study. Bayer, which purchased Monsanto in 2018, has not responded to requests for comments about the new study.
However, a statement from Bayer on glyphosate notes the EPA assessment and states that glyphosate has been shown to be totally evaluated and has been proven to be safe and efficient for weed control.
The new study authors note their new meta-analysis looks at all published human studies. This included a 2018 updated, government funded study called the Agricultural Health Study. Monsanto has noted that the updated AHS study proves there is no relation between glyphosate and cancer. In doing the new meta analysis, the researchers noted they looked at the highest exposed groups in every study because those people would probably have a higher risk if glyphosate herbicides lead to NHL.
Looking at people with real world, high level exposures to glyphosate make it not as likely that other confounding factors could skew the results. The authors said if there is no real connection between cancer and the chemical, then even the people with the highest level of exposure should not get cancer at higher rates.
In addition to reviewing human studies, researchers also reviewed other sorts of glyphosate studies, including those that were done on animals. Together the all of the meta analysis done to date, including the ones done in the new study, reported the same major finding: being exposed to glyphosate is associated with a higher cancer risk.
According to David Savitz, a professor of epidemiology at Brown University, the new work was well performed but there was a lack of new information. He suggested that it means there should still be concern and need for a regular reassessment but it does not clearly answer the question about the likelihood of glyphosate to cause cancer.
Glyphosate was first used by Monsanto as an herbicide in 1974. Usage in the agriculture industry has grown in the last 20 years, especially since the ‘green burndown’ practiced was started. This is where glyphosate herbicides are applied just before they are harvested are more likely to have high residues of glyphosate, leading to higher exposures among consumers. (medicalxpress.com).
UK Soil Association Response
In the UK, the Soil Association stated the new study was further evidence that the UK government needs to support its farmers so that it can stop relying on glyphosate on its crops. It was noted that UK pesticide use has dramatically increased in the last decades, with farmers getting very little support to innovate and transition to more environmentally friendly systems and practices, such as organic farming and agroforestry.
By using ecosystem services first and chemicals as the last resort, it is still possible to produce ample food supplies and reducing the risk of cancer in the general population. (fwi.co.uk).
- Weedkilling Products Increase Cancer Risk. (2019). Retrieved from https://www.theguardian.com/business/2019/feb/14/weed-killing-products-increase-cancer-risk-of-cancer
- Exposure to Chemical Roundup. (2019). Retrieved from https://medicalxpress.com/news/2019-02-exposure-chemical-roundup-cancer.html
- Glyphosate Exposure Increases Cancer Risk. (2019). Retrieved from https://www.fwi.co.uk/arable/crop-management/glyphosate-exposure-increases-cancer-risk-up-to-41-study-finds