As the leading glyphosate manufacturer, global chemical giant Bayer AG’s agrichemical unit Monsanto recently challenged a California $289 million jury verdict that favored a school groundskeeper Dewayne Johnson. He alleged the lack of a warning on this company’s glyphosate-based weed-killers, gave him a cancer, non-Hodgkin’s lymphoma. Glyphosate, mostly sold under the brand name Roundup, is probably the most widely used active ingredient in herbicides worldwide and has also been in a huge controversy. Earlier, in end 2017, both the EU while re-approving its use for 5 years and the U.S. Environmental Protection Agency, concluded that the chemical is “not a likely carcinogen” to humans. However, the World Health Organization in 2015 had classified glyphosate as “probably carcinogenic to humans.”
WHAT IS GLYPHOSATE
Glyphosate is a non-selective herbicide that prevents most plants from making certain proteins needed for plant growth via blocking a specific enzyme pathway, called the shikimic acid pathway. While some high dose animal studies in the laboratory suggest glyphosate has carcinogenic potential, human studies seem to be inconclusive so far.
Its use is likely to increase further as an ingredient of commercial herbicides because it is one of the first against which many important crops have been genetically modified to increase their tolerance and kill the weeds. Also, it is used in various settings by both professional agriculturists, applicators and small consumers, so the footprint is really vast. Unintended human poisoning can occur in complex, variable ways as commercial brands contain glyphosate concentrations varying from 41% to 1%, along with other molecules like surfactants, ions, anti-foaming agents, etc. Management is symptomatic and supportive, skin decontamination with soap and water is also recommended for such accidental exposures.
It may also affect fish and wildlife indirectly by altering the animals’ habitat. Recent reports in scientific journals and from University researchers have discussed disappearance of entire bee colonies as a consequence of using glyphosate.
WHY SHOULD YOU CARE
Organic growers, environmentalists and other advocacy, activist groups have been concerned about lack of sufficient evidence to justify its use as one component of chemical cocktails. These are used in a sequence during the food growing-harvesting process, so their concerns are with respect to the effects on soil, microorganisms, water, emergence of resistant weeds and even processed foods like bread or cereals. Reputed food security activist authors like Tony Mitra and scientist researchers on the subject like Stephanie Seneff of MIT, seem to have also indicated gaps in evidence related to both the products of sugarcane, & tea plantations in mostly developing countries. The possible health impact on its resident workers, ranging from kidney dysfunction, esophageal cancers to autoimmune diseases, autism and dementia has also been highlighted.
Back in 2015, when the International Agency for Research on Cancer (IARC) arm of WHO announced in top scientific publications like Lancet, that the world’s most widely used herbicide glyphosate is probably linked to cancer, there was a huge backlash from the industry. Several rounds of ‘independent’ reviews from Nature, Science Media Centre, to other outlets on both sides of the divide, followed. This debate is still continuing, standing on the fine line between sufficient evidence of human cancer and interpretation of mostly animal studies or mechanistic toxicology evidence. Opposing sides are negotiating positions based on specific category of classification in the WHO assessment (Class 2A vs 2B) to outright rejection of the IARC assessment. Experts also have to consider the practical difficulties of conducting epidemiological studies on farmers who use multiple chemicals at various stages of cultivation and other difficult to control variables. However, the recent expression of concern by the Critical Reviews in Toxicology Journal against some of the authors of an “Independent review of the carcinogenetic potential of glyphosate” for not disclosing ties to Monsanto, does lead to further controversy and accusations of “ghost writing” of safety reviews by Monsanto executives.
The wave of expressed discontent noted online from various activists, advocates, NGOs, free market proponents, manufacturers combined with the legal & financial exposure of Bayer itself, has pointed toward a broader societal assessment in the decision-making process on pesticide registration. Whether people push for testing foods for glyphosate and whether glyphosate attracts more policy attention, remains to be seen as the jury is still out there.