Assessed crops are sprayed with far lower levels of herbicides than are used in real-farm conditions, so risks are underestimated
Two important new papers have been published (see abstracts below this article) showing that the GM herbicide-tolerant soybean crops assessed by regulators are not representative of what actually gets grown and put out into the marketplace. This is because the crops that are grown by industry in field trials and fed to laboratory animals in feeding studies have been sprayed with less herbicide and in fewer applications compared with real-farm growing conditions. This matters because the data from these field trials and animal feeding studies are used by regulators to assess the crop in question for health and environmental safety.
In other words, because the crops grown in the field trials are sprayed with much less herbicide than is current in real farming conditions, the health and environmental risks posed by these crops are likely to be seriously underestimated.
Both the new studies are co-authored by Thomas Bøhn of the Institute of Marine Research in Norway. The first study is co-authored by Juliana Miyazaki, Christoph Then, and Andreas Bauer-Panskus, all from the research platform Testbiotech, as well as Wolfram Reichenbecher of the German Federal Agency for Nature Conservation (BfN). The second is co-authored by Prof Erik Millstone of the University of Sussex in the UK.
While ever-increasing volumes of herbicide have been applied over time to GM crop fields in order to try to control herbicide-resistant weeds, the new study found that the crops assessed by regulators are often dosed only with the original, lower volumes of herbicide that were used prior to the spread of resistant weeds. For example, in 1998, 1.03 kg of active ingredient (glyphosate) per hectare was applied to GM glyphosate-tolerant soybeans. But currently the total amount of glyphosate applied to these soybeans has climbed by up to 10-fold: to 6-7 kg or even 8–10 kg per hectare in some regions, such as Argentina and Paraguay.
As the authors point out, there is more than one way in which the amount of herbicide applied to a GM crop can impact its health and environmental safety profile. The first and most obvious is via herbicide residues, with higher levels of residue potentially posing a higher health and environmental risk. A second less well recognised route is via the composition of the plant, which can change in response to the amount and type of herbicides applied – as a separate study on the glyphosate-tolerant GM maize NK603 has shown.
So growing the trial crops with less herbicide than normal will under-represent the risks involved.
Furthermore, crops with multiple herbicide resistance can be treated with herbicide combinations, resulting in new residue mixtures. Thus the authors recommend that for crops with multiple herbicide resistance, herbicide residues should be considered and assessed in combination before any authorisation for GM plants can be granted. This currently does not happen.
In one case – Dow DuPont's GM soybeans tolerant to glyphosate, 2,4-D, and glufosinate – a herbicide that the crop was engineered to be grown with was not even applied in the field trial. The authors found that "Soybeans for the feeding study were sprayed with much less glyphosate and 2,4-D and no glufosinate at all."
They continued, "Therefore, the feeding study, which could have shown adverse effects of herbicide residues or other parameters, tested non-representative soybean material."
Those who argue that most residues are found within regulatory safety limits and thus can be ignored are shown to be wrong by a point made in the second study below, which notes, "Feeding studies in Daphnia magna [a small freshwater crustacean] have shown dose-related adverse effects (mortality, reduced fecundity and delayed reproduction) of glyphosate residues in soybeans, even at glyphosate concentrations below allowed residue levels."
In addition, another study by a different research group shows that glyphosate and the glyphosate-based herbicide Roundup disrupt the gut microbiome and causes non-alcoholic fatty liver disease at levels deemed by regulators to be safe. Yet another study shows that Roundup causes non-alcoholic fatty liver disease at very low doses far below what is typically found in the diet.
Due to all these findings, we support the conclusion of the authors of the first study below: "Current risk assessment practice for HT GE plants cannot be considered to fulfil EU regulatory standards which require the safety of food and feed to be demonstrated. It is much more likely that concerns about the health risks of HT GE plant material used for food and feed have been underestimated. We therefore conclude that the EU risk assessment of food and feed derived from HT GE plants needs substantial improvement."
1. Insufficient risk assessment of herbicide-tolerant genetically engineered soybeans intended for import into the EU
Juliana Miyazaki, Andreas Bauer-Panskus, Thomas Bøhn, Wolfram Reichenbecher & Christoph Then
Environmental Sciences Europe volume 31, Article number: 92 (2019)
The introduction of herbicide-tolerant (HT) genetically engineered (GE) soybeans has raised new challenges for the European risk assessment of imported food and feed. Food and feed products derived from these plants may show specific patterns of chemical residues and altered nutritional composition. Furthermore, there has been a substantial increase in the usage of herbicides in soybean production due to the emergence of resistant weeds. This concerns particular glyphosate-based herbicides and also other herbicides. In this review, we give an overview of available data regarding glyphosate application on HT GE soybeans in North and South America. We have further compared this data with herbicide applications in experimental field trials conducted by the industry. We conclude that field trials carried out for risk assessment purposes do not generally represent the real agronomic conditions in commercial HT GE plant cultivation. In most cases, neither the applied dose nor the number of applications match real conditions. This finding is especially relevant for risk assessment since a review of relevant publications shows that the amount and timing of spraying glyphosate as a complementary herbicide onto HT GE plants can impact their composition; this is relevant to EFSA comparative risk assessment of GMOs. Further, closely related issues were identified that overlap with EU GMO and pesticide regulation, but are not currently considered. These issues concern indirect, cumulative and combinatorial effects as well as the assessment of mixed toxicity. Consequently, current risk assessment practice for HT GE plants cannot be considered to fulfil EU regulatory standards which require the safety of food and feed to be demonstrated. It is much more likely that concerns about the health risks of HT GE plant material used for food and feed have been underestimated. We therefore conclude that the EU risk assessment of food and feed derived from HT GE plants needs substantial improvement.
2. The introduction of thousands of tonnes of glyphosate in the food chain - An evaluation of glyphosate tolerant soybeans
Bøhn T, Millstone E
Foods. 2019 Dec 11;8(12). pii: E669. doi: 10.3390/foods8120669.
Glyphosate-tolerant (GT) soybeans dominate the world soybean market. These plants have triggered increased use of, as well as increased residues of, glyphosate in soybean products. We present data that show farmers have doubled their glyphosate applications per season (from two to four) and that residues of late season spraying of glyphosate (at full bloom of the plant) result in much higher residues in the harvested plants and products. GT soybeans produced on commercial farms in the USA, Brazil and Argentina accumulate in total an estimated 2500-10,000 metric tonnes of glyphosate per year, which enter global food chains. We also review studies that have compared the quality of GT soybeans with conventional and organic soybeans. Feeding studies in Daphnia magna have shown dose-related adverse effects (mortality, reduced fecundity and delayed reproduction) of glyphosate residues in soybeans, even at glyphosate concentrations below allowed residue levels. We argue that GT soybeans need to be tested in fully representative and realistic contexts. However, the current risk assessment system has only required and received data from field trials with beans that were sprayed with much lower doses of glyphosate as compared to contemporary commercial farms. This has left knowledge gaps and a potentially serious underestimation of health risks to consumers.