Glyphosate-based Products Research Articles

The Glyphosate Saga in Luxembourg: The Annulment by the Judiciary of the Legislative Ban of Glyphosate-Based Products – A Breach of European Union Law?

Administrative Tribunal of Luxembourg, 15 July 2022, case no 44377 and Court of Appeal of Luxembourg, 31 March 2023, case no 47873COn 15 July 2022, the Administrative Tribunal of Luxembourg annulled the decisions by which the Luxembourg Minister for Agriculture, Viticulture, and Consumer Protection had banned all glyphosate-based products. On 31 March 2023, the Court of Appeal upheld the ruling of the Administrative Tribunal. The ground of annulment was the breach by the Luxembourg State of the adversarial principle enshrined in Article 9 of the Grand-Ducal Regulation of 8 June 1979. Yet, for the sake of completeness, the Administrative Tribunal and the Court of Appeal verified the compliance of the decisions banning glyphosate-based products with Articles 36, 41 and 44 of Regulation no 1107/2009. Against this backdrop, this case note provides a critical assessment of the rulings of the Administrative Tribunal and the Court of Appeal from the perspective of European Union law. This analysis might prove to be useful as it enables us to shed light on the conditions allowing Member States to withdraw the authorisation of plant protection products under Regulation no 1107/2009 as well as to identify the hurdles that Member States might need to overcome when banning glyphosate-based products from their territory.

Continuous glyphosate applications affect plant development of mangrove species from coastal wetlands: Rhizophora mangle and Pachira aquatica

Glyphosate based herbicides not only affect unwanted plants in agricultural and urban areas, but also impact non-target vegetation, including its associated biome. The effect of the repeated application of these products on growth remains undetermined for many ecologically important trees. Coastal wetlands accumulate pollutants and therefore are exposed to different compounds at varying concentrations. This exposure may interfere with wetlands' ability to maintain essential ecosystem functions. Therefore, this study aimed to evaluate the effect of different concentrations of a commonly used glyphosate-based herbicide on mesocosms planted with juvenile Rhizophora mangle and Pachira aquatica. We assessed the impact of herbicide treatment on plant growth as well as the subsurface CO2 efflux. Plants were transplanted to containers filled with fine gravel (substrate) and maintained under flooded conditions. Four different glyphosate treatments were investigated over a period of 124 days: in three treatments, glyphosate was added in two applications of either 25, 50, or 100 mg glyphosate acid equivalent (ae)/L, whereas in the fourth treatment, glyphosate was added in eight applications of 25 mg ae/L. Plant growth was measured (plant height, stem diameter, number of green leaves or leaflets) and subsurface CO2 efflux from the substrate was quantified. Different glyphosate concentrations resulted in different effects on plant growth for both species. Mesocosms that received continuous glyphosate applications exhibited reduced plant growth in the long term. Carbon dioxide efflux was reduced by different glyphosate concentrations. Our results contribute to further understanding the adverse impact that glyphosate-based products may have on ecologically important trees and their ecosystem services in coastal areas in the tropics.

Danger is just a click away–A survey on online shopping for glyphosate-based pesticides for gardening/horticulture

The vertiginous growth of consumers' preference for making purchases over the internet has been accompanied by the possibility of obtaining almost any type of product, with little perception of the inherent risks of this practice. In Brazil, although legislation has determined for more than a decade which concentrations and presentations of pesticides can be marketed, the lack of information and knowledge still prevails among the general public. The present study aimed to analyze information provided on glyphosate-based products marketed on Brazilian websites to determine possible factors that influence consumers' decision-making process. For this purpose, a form was prepared to collect information concerning positive and negative aspects of the products, mentions of risks, prices and quality assessments. Our results showed the presence of very few guidelines regarding human health risks (n = 3) or accident risks (n = 1) arising from the misuse of chemical agents on the websites but at the same time a greater concern to show the efficacy (n = 19), mode (n = 26) and dose of application (n = 23). Such findings allow us to affirm that there is still a great void of knowledge concerning risks of these chemical agents, which has been perpetrated by the apparent negligence of companies in providing such information and of the public authorities in supervising this activity. It is important that inspection measures are taken with regard to the quality and safety of the information disclosed in these media, improving consumers' perception of the risks of the practice both for their personal health and for the environment.

Quantification of the Potential Impact of Glyphosate-Based Products on Microbiomes

Glyphosate-based products (GBP) are the most common broad-spectrum herbicides worldwide. The target of glyphosate is the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) in the shikimate pathway, which is virtually universal in plants. The inhibition of the enzyme stops the production of three essential amino acids: phenylalanine, tyrosine, and tryptophan. EPSPS is also present in fungi and prokaryotes, such as archaea and bacteria; thus, the use of GBP may have an impact on the microbiome composition of soils, plants, herbivores, and secondary consumers. This article aims to present general guidelines to assess the effect of GBP on microbiomes from field experiments to bioinformatics analyses and provide a few testable hypotheses. Two field experiments are presented to test the GBP on non-target organisms. First, plant-associated microbes from 10 replicated control and GBP treatment plots simulating no-till cropping are sampled and analyzed. In the second experiment, samples from experimental plots fertilized by either poultry manure containing glyphosate residues or non-treated control manure were obtained. Bioinformatics analysis of EPSPS protein sequences is utilized to determine the potential sensitivity of microbes to glyphosate. The first step in estimating the effect of GBP on microbiomes is to determine their potential sensitivity to the target enzyme (EPSPS). Microbial sequences can be obtained either from public repositories or by means of PCR amplification. However, in the majority of field studies, microbiome composition has been determined based on universal DNA markers such as the 16S rRNA and the internal transcribed spacer (ITS). In these cases, sensitivity to glyphosate can only be estimated through a probabilistic analysis of EPSPS sequences using closely related species. The quantification of the potential sensitivity of organisms to glyphosate, based on the EPSPS enzyme, provides a robust approach for further experiments to study target and non-target resistant mechanisms.

Quantification of the Potential Impact of Glyphosate-Based Products on Microbiomes.

Glyphosate-based products (GBP) are the most common broad-spectrum herbicides worldwide. The target of glyphosate is the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) in the shikimate pathway, which is virtually universal in plants. The inhibition of the enzyme stops the production of three essential amino acids: phenylalanine, tyrosine, and tryptophan. EPSPS is also present in fungi and prokaryotes, such as archaea and bacteria; thus, the use of GBP may have an impact on the microbiome composition of soils, plants, herbivores, and secondary consumers. This article aims to present general guidelines to assess the effect of GBP on microbiomes from field experiments to bioinformatics analyses and provide a few testable hypotheses. Two field experiments are presented to test the GBP on non-target organisms. First, plant-associated microbes from 10 replicated control and GBP treatment plots simulating no-till cropping are sampled and analyzed. In the second experiment, samples from experimental plots fertilized by either poultry manure containing glyphosate residues or non-treated control manure were obtained. Bioinformatics analysis of EPSPS protein sequences is utilized to determine the potential sensitivity of microbes to glyphosate. The first step in estimating the effect of GBP on microbiomes is to determine their potential sensitivity to the target enzyme (EPSPS). Microbial sequences can be obtained either from public repositories or by means of PCR amplification. However, in the majority of field studies, microbiome composition has been determined based on universal DNA markers such as the 16S rRNA and the internal transcribed spacer (ITS). In these cases, sensitivity to glyphosate can only be estimated through a probabilistic analysis of EPSPS sequences using closely related species. The quantification of the potential sensitivity of organisms to glyphosate, based on the EPSPS enzyme, provides a robust approach for further experiments to study target and non-target resistant mechanisms.

Estimated herbicide use in the commercial forest sector in South Africa

ABSTRACT This paper examines herbicide use in South African commercial plantations in 2017/18 across three climate zones (cool temperate − CT, warm temperate − WT and subtropical − ST) for three genera (eucalypts, pines and acacias) grown for two end-products (sawn timber and pulpwood). Herbicide information was obtained from 46 timber plantations owned by six forestry companies, comprising 343 872 ha surveyed. The herbicide survey was divided into three climate zones due to increased vegetation growth (and hence more herbicide use) on more productive ST sites compared to moderately productive WT sites, with the lowest vegetation growth on CT sites (lower productivity). The survey was further divided into three distinct vegetation management phases associated with plantation forestry (pre-establishment, re-establishment and post-establishment) to compare herbicide use between genera grown on an annual basis. A total of 188 288 kg (or 0.55 kg ha−1) of herbicide active ingredient (a.i.) was applied in the area surveyed. Glyphosate-based products accounted for 97% of all the herbicides applied, and metazachlor and triclopyr butoxy ethyl ester accounted for 2%. Overall, herbicide use per hectare on an annual basis was highest in the ST zone, followed by the WT and CT zones. For both the CT and WT zones, the general trend was that the pre-establishment phase received noticeably more herbicides, followed by the re- and post-establishment phases (prerepost). This trend remained similar for the genera grown (prerepost), with hardwoods receiving more herbicides than softwoods. In contrast, there was little difference in herbicide use between the re- and pre-establishment phases for the ST zone, with the post-establishment phase being noticeably less. Besides providing benchmark data related to herbicide use in South African plantations, future research should investigate the potential for a reduction in herbicide use in those regions, vegetation management phases and management regimes where it is highest.

PSVIII-17 Modeling of glyphosate speciation in rumen fluid of cattle

Abstract Glyphosate, the active ingredient in Roundup® agricultural herbicides, is used on crops that are commonly grown for animal feed. Even though there has not been empirical data to suggest that animal productivity and health are affected when glyphosate-based products are used as labeled, accusations based on hazard identification alone have circulated widely. One of these accusations originates regarding a patent that was never held by Monsanto (now part of the Bayer Group) that did not include glyphosate. This claim hypothesizes that glyphosate could chelate minerals in the gut and prevent absorption. Formation constants measure the strength of complexation between metal ions and ligands and can be used to model the speciation in mixtures of minerals, amino acids, VFAs, and glyphosate as they exist in the rumen. The amines and carboxylic acids of all amino acids and functional side chains such as the imidazole group of histidine are potential donors for binding minerals. Likewise, carboxylic acid groups from VFAs are prevalent sources for binding of minerals. Literature references of concentrations of minerals and amino acids were used along with a measurement of glyphosate, and speciation calculations were performed at three pH’s commonly encountered in the rumen (5.8, 6.3 and 6.8). This calculation identified all species present at ≥0.01%. Using pH=6.3 as an example, 55.1% of cobalt is present as free Co2+, 28.6% is bound to a VFA (acetate, propionate or butyrate), and 13.1% is bound to histidine. The remaining 1.6% is distributed among Ala, Asp, Cys, Glu, Gly, Lys, Met, Ser, Thr, NH3 and OH. Similar results by ligand will be presented for Fe, Zn, Cu, Mn, Ca, His, Cys, and Glu. Data from these models confirm that glyphosate is a relatively weak chelator that should not have deleterious effects in the rumen.

Developmental and lethal effects of glyphosate and a glyphosate-based product on Xenopus laevis embryos and tadpoles.

Effects of pure glyphosate and a glyphosate-based product were evaluated comparatively using two embryonic development stages of Xenopus laevis as model system. When pure glyphosate was applied in pH adjusted media, lethal or developmental effects were not observed at concentrations up to 500mgL-1. The 96h LC50 values for the commercial herbicide, in contrast, were 32.1 and 35.1mg active ingredientL-1 for embryos and tadpoles, respectively. Since pure glyphosate has no effect on the selected biomarkers, it is thought that developmental toxic effects caused by glyphosate-based products are increased mainly due to formulation additives.

Farming without Glyphosate?

Recent statements from scientific organisations and court decisions have resulted in widespread public interest and concern over the safety of glyphosate, the most popular and effective herbicide used worldwide. Consequently, glyphosate-based products are under intense scrutiny from governments at all levels. Some jurisdictions have already banned or restricted its use, which will adversely impact international trade in bulk grain commmodities if glyphosate residues are detected. The possibility of farming without glyphosate is becoming an important issue facing the agri-food research and development sector. Contingency plans need to be formulated if that scenario becomes a reality. In this review, we briefly summarize international events that have led to this possible situation, describe current glyphosate usage in major agronomic field crops worldwide, outline possible alternatives to glyphosate in two agroregions and perform bioeconomic model scenarios of southern Australian broadacre cropping systems without the herbicide. Model predictions suggest that we can farm profitably without glyphosate by consistently utilizing key non-herbicidal weed management practices combined with robust pre-emergence soil residual herbicide treatments. However, maintaining low weed seed banks will be challenging. If the social license to use glyphosate is revoked, what other pesticides will soon follow?

Increased severity associated with tallowamine in acute glyphosate poisoning

Context: During the re-approval process of glyphosate in Europe, it was mentioned that glyphosate-based products (GBF) were more toxic than glyphosate alone. This phenomenon was attributed to the surfactants and among them, polyethoxylated tallowamine (POEA) has been suspected to significantly contribute to the toxicity of glyphosate products. In animal data acute oral toxicity of POEA has been suggested to be greater than glyphosate toxicity in animal studies. There are no data, however, comparing the clinical signs and severity of acute human poisoning with tallowamine-containing GBF (TA) and non-tallowamine-containing GBF (NTA). The aim of this study was to compare the severity of oral poisoning between TA and NTA cases, reported to the French Poison Control Centres (PCC) over 7 years.Methods: This is a retrospective study of cases of oral exposure to GBF reported to French PCCs between January 1st, 2008 and December 12th, 2014. The formulation of every GBF was reviewed using the PCC national database of products and compositions, to identify cases involving TA, NTA, or GBF with unknown co-formulants.Results: Between 2008 and 2014, 1362 cases of GBF ingestion were registered in the PCC national database of poisoning cases. Among them, 429 were symptomatic acute cases of ingestion of GBF. There were 235 exposures to TA, 105 to NTA, and 89 to unknown GBF. There were more severe cases in the TA group than in the NTA group (p = 0.037).Discussion: The present study shows that POEA rather than other co-formulants leads to more severe symptoms in those patients ingesting GBF. The acute toxicity of POEA might be explained by its irritating properties; in experimental studies, it caused skin irritation and severe eye and mucous membranes irritation.Conclusion: In this study, severe respiratory symptoms were also more frequently reported in the TA group. The surfactant properties of POEA are likely to cause aspiration pneumonitis which is a plausible explanation for the respiratory failure complicating severe GBF poisoning cases.

Glyphosate runoff and its occurrence in rainwater and subsurface soil in the nearby area of agricultural fields in Argentina.

Glyphosate-based products are among the most important herbicides applied to enhance the production of food commodities, leading to the worldwide spread of this herbicide. The main goal of this work was to evaluate the off-site transport of glyphosate in a runoff experiment. A micro-plot experiment was conducted to assess the retention, leaching and runoff of glyphosate under rainfall simulation. Glyphosate losses due to spray drift were estimated. Concentrations of glyphosate and AMPA were determined in rainwater and subsurface soil from agricultural and riparian zones. Analyses were performed with UHPLC-MS/MS. Experimental results demonstrated that 88.1% of the applied glyphosate was retained in the surface soil layer (0–9 cm). Glyphosate leaching was negligible compared to its runoff (3.9%) and spray drift (6.9%). Thus, the risk of groundwater pollution would be lower in comparison to that of both surface waters and rainwater. Moreover, under field conditions, glyphosate and AMPA were detected in 52% of the rainwater samples and glyphosate was detected up to 1 m in both soil profiles. Although the experimental application was made with hand-held knapsack under low wind condition to minimize glyphosate aerial dispersion, the spray drift was the main source of glyphosate off-site transport, degrading air quality and rainwater for human consumption. The balance among spray drift, runoff and soil absorption of glyphosate when it was sprayed close to the soil surface (hand held equipment), demonstrated the importance of spray drift in mass balance studies during runoff and leaching experiments with glyphosate.

The Risks Associated with Glyphosate-Based Herbicide Use in Planted Forests

Glyphosate-based herbicides are the dominant products used internationally for control of vegetation in planted forests. Few international, scientific syntheses on glyphosate, specific to its use in planted forests, are publically available. We provide an international overview of the current use of glyphosate-based herbicides in planted forests and the associated risks. Glyphosate is used infrequently in planted forests and at rates not exceeding 4 kg ha1. It is used within legal label recommendations and applied by trained applicators. While the highest risk of human exposure to glyphosate is during manual operational application, when applied according to label recommendations the risk of exposure to levels that exceed accepted toxicity standards is low. A review of the literature on the direct and indirect risks of operationally applied glyphosate-based herbicides indicated no significant adverse effects to terrestrial and aquatic fauna. While additional research in some areas is required, such as the use of glyphosate-based products in forests outside of North America, and the potential indirect effects of glyphosate stored in sediments, most of the priority questions have been addressed by scientific investigations. Based on the extensive available scientific evidence we conclude that glyphosate-based herbicides, as typically employed in planted forest management, do not pose a significant risk to humans and the terrestrial and aquatic environments.

Side-Effects of Glyphosate to the Parasitoid Telenomus remus Nixon (Hymenoptera: Platygastridae).

The aim of this study was to compare the side-effects of glyphosate to the parasitoid Telenomus remus Nixon (Hymenoptera: Platygastridae) when parasitoids were exposed to this chemical at the pupal (inside host eggs) and adult stages. Bioassays were conducted under laboratory conditions according to the International Organization for Biological Control (IOBC) standard methods for testing side-effects of pesticides to egg parasitoids. Different glyphosate-based pesticides (Roundup Original®, Roundup Ready®, Roundup Transorb®, Roundup WG®, and Zapp Qi®) were tested at the same acid equivalent concentration. Treatments were classified following the IOBC toxicity categories as (1) harmless, (2) slightly harmful, (3) moderately harmful, and (4) harmful. When tested against T. remus adults, Roundup Original®, Roundup Ready®, Roundup Transorb®, and Roundup WG® reduced parasitism 2days after parasitoid emergence, being classified as slightly harmful. Differently, when tested against T. remus pupae, all tested glyphosate-based products did not differ in their lethal effect and therefore did not reduce T. remus adult emergence or parasitism capacity, being classified as harmless. However, differences on sublethal toxicity were found. Parasitism of individuals emerging from parasitized eggs sprayed at the pupal stage of T. remus with Zapp Qi® was lower compared to control, but parasitism was still higher than 66%, and therefore, Zapp Qi® was still classified as harmless. In conclusion, all tested glyphosate-based products can be used in agriculture without negative impact to T. remus as none was classified as harmful or moderately harmful to this parasitoid when exposure occurred at the pupal or adult stages.

Comparative toxicity of two glyphosate-based formulations to Eisenia andrei under laboratory conditions

Glyphosate-based products are the leading post-emergent agricultural herbicides in the world, particularly in association with glyphosate tolerant crops. However, studies on the effects of glyphosate-based formulations on terrestrial receptors are scarce. This study was conducted to evaluate the comparative toxicity of two glyphosate-based products: Roundup FG (monoammonium salt, 72% acid equivalent, glyphosate-A) and Mon 8750 (monoammonium salt, 85.4% acid equivalent, glyphosate-B), towards the earthworm Eisenia andrei. Median lethal concentration (LC50) showed that glyphosate-A was 4.5-fold more toxic than glyphosate-B. Sublethal concentrations caused a concentration-dependent weight loss, consistent with the reported effect of glyphosate as uncoupler of oxidative phosphorylation. Glyphosate-A showed deleterious effects on DNA and lysosomal damage at concentrations close to the applied environmental concentrations (14.4μg ae cm−2). With glyphosate-B toxic effects were observed at higher doses, close to its LC50, suggesting that the higher toxicity of formulate A could be attributed to the effects of some of the so-called “inert ingredients”, either due to a direct intrinsic toxicity, or to an enhancement in the bioavailability and/or bioaccumulation of the active ingredient. Our results highlight the importance of ecotoxicological assessment not only of the active ingredients, but also of the different formulations usually employed in agricultural practices.