EU regulators dismissed key scientific evidence linking glyphosate to rodent tumours in a positive assessment they gave for continued sales of the substance last week, according to a new report by environmental campaigners.
Glyphosate is the world’s most widely used weedkiller and its EU relicensing has become a touchstone in a wider battle between environmentalists and agribusiness over the future of farming.
A separate study last week found that glyphosate was seriously damaging the ability of wild bumblebees to regulate colony temperatures.
Meanwhile the report by the NGOs says that the assessment by the European Chemical Agency (Echa) contains “serious scientific shortcomings that question its scientific objectivity”, because of an alleged rejection of findings from 10 out of 11 studies which link the herbicide ingredient to tumour formations.
Dr Peter Clausing, the report’s co-author, said: “Animals exposed to glyphosate developed tumours with significantly higher incidences compared to their unexposed control group – an effect considered as evidence of carcinogenicity by both international and European guidelines.
“Yet, the EU risk assessors have dismissed all the tumour findings from their analysis, concluding that they all occurred by chance and that none of them was actually related to glyphosate exposure.”
Seven of the animal studies are backed by historical control data, and five of them show that mice and rats developed more than one type of tumour, the report says. In four of the rodent studies, the number of tumours rose as the glyphosate dose increased, it adds.
Malignant lymphomas, kidney and liver tumours and skin keratoacanthomas were all found in the studies, said Prof Christopher Portier, an expert whose analysis informed the new report by the Health and Environment Alliance.
“Glyphosate fuels cancer,” said Portier, who was an invited specialist for the World Health Organization (WHO) panel that found glyphosate to be “probably carcinogenic to humans” in 2015.
“No matter how you look at it, there is more than enough evidence of carcinogenicity, and this evidence meets the criteria to classify glyphosate as a substance presumed to have carcinogenic potential for humans,” he said.
Echa’s decision not to apply even a secondary carcinogenicity classification – used where evidence is limited – was “incomprehensible”, the report said.
The latest Echa review stuck closely to recommendations made by an “Assessment Group on Glyphosate” made up of experts from four countries – France, the Netherlands, Hungary and Sweden.
The full opinion of Echa’s risk assessment committee (RAC), which sets the scene for a more definitive ruling from the European Food Safety Authority (Efsa) next year, will be published in mid-August.
But an online summary concludes that it is “not justified” to classify glyphosate as a carcinogen, although it is toxic to aquatic life and causes serious eye damage.
The chemicals agency says that its RAC produced a “complete and thorough review” of all the relevant studies, including the papers that found tumours in mice and rats.
An Echa spokesperson said: “The findings from the studies conducted with glyphosate were not dismissed but a causal relationship was not established between exposure to the substance and the incidences of tumours observed.”
Several regulators have disputed the WHO’s carcinogenicity finding for glyphosate, including the EU’s European Food Safety Authority and the US Environmental Protection Agency.
Glyphosate was originally developed by the US agribusiness firm Monsanto, which was sold to the German chemicals giant Bayer for $63bn (£50bn) in 2018.
That deal led Bayer to pick up the tab for a series of ongoing court disputes over glyphosate’s alleged links to non-Hodgkin lymphoma. In the two and a half years after Monsanto lost its first US court case over the RoundUp pesticide, Bayer’s share fell by 45%. The Wall Street Journal described the acquisition as “one of the worst corporate deals” in recent times.
Utz Klages, a spokesperson for Bayer, welcomed the Echa assessment, noting that it had also not classified glyphosate as having specific target organ toxicity, or as being a mutagenic or reprotoxic substance.
He said: “We remain convinced that we have a strong science-based rationale for a renewed approval of glyphosate, which would continue to provide farmers and professional users with an important technology in an integrated weed management approach.
“Glyphosate-based herbicides play, and will continue to play, an important role in sustainable agriculture and in Bayer’s product portfolio.”
Attention in Europe’s glyphosate debate will now switch to Efsa’s next assessment of the chemical, which it said last week would be published in July 2023, a year later than planned.
The EU is supposed to decide whether to relicense the product by 15 December 2022, although a temporary extension of the existing licence may also be possible.
