Glyphosate risks and its reevaluation
Glyphosate has been the most widely used herbicide throughout history, both in America and the rest of the world. One of the most well-known products containing glyphosate is the Monsanto company Roundup, which has been used for more than 40 years. Below is a summary of the latest research results on the pesticide and news on its reevaluation.

Glyphosate has been under attack for years, which intensified in 2015 when the WHO Agency for Research on Cancer (IARC) declared the substance a Group 2A carcinogen (probable human carcinogen). According to the evaluation of the European Chemicals Agency (ECHA), glyphosate seriously damages the eyes and is harmful to aquatic life, while its classification as a carcinogen was not considered justified. The use of the substance in the EU is currently authorized until December 15, 2023, but its review is currently in progress.

Research findings

Low levels of glyphosate were detected in a quarter of urine samples examined in an Irish study. Researchers from the University of Galway in Ireland examined the baseline exposure in the urine of 68 Irish families, a total of 226 individuals, in 2019-2020. Glyphosate was detected in 26 percent of the samples, and AMPA in 59 percent. The daily intake estimated from the concentrations was equivalent to or below 3% of the EFSA ADI value.

Among the investigated families there were also those engaged in farming, and although no statistical difference was shown between those engaged in farming and those not engaged in farming, higher concentrations were measured in the urine of the former in some cases, which was explained by the use of glyphosate-containing products the previous day.

The higher prevalence of AMPA can be explained by the fact that exposure can also occur through the consumption of food and water. The research was carried out in the framework of the European HBM4EU project, during which several high-priority compounds (including glyphosate and AMPA) were designated for which additional information regarding human exposure needs to be collected.

More disturbing findings were made by a recent US government study, which showed high levels of glyphosate in urine samples and linked it to signs of oxidative stress. Oxidative stress is a characteristic feature of carcinogenic substances, but it can also play a role in the long-term development of other chronic diseases (including diabetes, heart disease, fertility problems).

Researchers from the National Institutes of Health and CDC have detected similar levels of glyphosate in the urine not only of farmers but also of other consumers, which suggests that the general population may also be concerned by these effects.

The German company Bayer, which bought Monsanto, questioned to the reliability of the research, mentioning its findings contradict other government research, and glyphosate exposure cannot be clearly linked to oxidative stress, other factors and their combinations may have played a role in its development.

According to the CDC's report last year, glyphosate was found in more than 80% of the examined child and adult urine samples (1,885 out of 2,310).

In an American study last year examining the urine of 347 pregnant women, a higher level of oxidative stress biomarkers was detected in the samples in which AMPA was also present. The endocrine disruptor effect of AMPA has already been demonstrated.

Meanwhile, several lawsuits are pending against the companies Monsanto and Bayer due to the alleged carcinogenic effects of glyphosate.

While several countries have banned the use of glyphosate, regulatory bodies in other countries consider it safe and not carcinogenic. The Environmental Protection Agency (EPA) is currently reevaluating the safety of glyphosate. In 2020, the EPA found glyphosate to be of no concern to human health, but this was overturned by court last year.

In a study published in July 2023, German researchers found that aversive learning in bumblebees is impaired by exposure to glyphosate. Recognizing that much more information than the mortality rate is needed when studying the effects of agrochemicals, researchers at the University of Konstanz studied the effect of long-term exposure to glyphosate on bees' locomotion, phototaxis and learning abilities. Non-lethal effects are considered equally important as lethal effects, as they can reduce an individual's chances of reproduction and survival. The researchers already discovered last year that the collective thermal behavior of bees was damaged by chronic glyphosate exposure, i.e. they were less able to keep their brood warm in case of scarce resources. In the current study, more than 400 bumblebee workers were examined and found that specimens exposed to glyphosate long-term were unable to learn aversive behavior, which may contribute to their increased mortality. Glyphosate exposure also slightly reduced their walking speed and reduced their attraction to UV light relative to blue light. According to biologists, even a slight shift in UV sensitivity can have broad implications on their navigation and foraging efficiency.

Reauthorization in the EU

Meanwhile, in July 2023, EFSA's reevaluation on the subject was published. The evaluation of the effects of glyphosate on human, animal and environmental health did not identify critical areas of concern.

Regarding biodiversity, experts recognized that the risks associated with representative uses of glyphosate were complex and multifactorial. It was noted that there were no harmonized methods and no agreed specific protection targets, and the available information overall does not allow firm conclusions to be drawn in this area of risk assessment. Regarding the ecotoxicological assessment, a high long-term risk to mammals was identified in 12 of the 23 proposed uses of glyphosate according to the conservative (tier 1) risk assessment approach. No suitable data were available for a more refined risk assessment in this area.

Issues that could not be finalized include the assessment of one of the impurities of glyphosate, the dietary risk assessment of consumers and the assessment of the risk to aquatic plants.

Among the outstanding issues was the lack of information on the toxicity of one of the components of the glyphosate-based pesticide formulation submitted for evaluation.

According to the leaked draft proposal of the European Commission, citing the latest scientific opinion of the EFSA, it may be expected that glyphosate-based products will continue to meet the safety requirements of EU legislation, allowing it to be authorized for a standard period of 15 years.

The active ingredient glyphosate was last approved in the EU in 2017 for a five-year period, in the context of a controversial procedure. The five-year license was extended for another 12 months last December. The Commission presented the proposal document to the representatives of the Member States on July 11 and 12. After discussing the topic in September, the member states are expected to vote on reauthorization in October. The Commission is already facing a lot of criticism from non-governmental organizations because of its action.

Currently there is no agreement between the member states regarding the interpretation of the EFSA opinion. According to the German Minister of Agriculture, for example, the verdict was not based on a comprehensive assessment, as EFSA did not sufficiently take into account a key factor, the effects on nature. The Spanish minister, on the other hand, fully accepts the EFSA opinion. The German government has committed to taking glyphosate off the market in Germany from the end of 2023, however, if the decision to reauthorize glyphosate is made, the legal scope of a national ban will be very limited.


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