Objection to DP73496 canola field trial application
We hereby lodge our objection to the application for genetically modified (GM) canola field trials, event DP73496. DP73496 canola expresses the GAT4621 protein, encoded by the gat4621 gene, that confers tolerance to glyphosate-based herbicides.
Documented risks of persistence and contamination are unduly dismissed in application
In recent years, South Africa’s canola cultivation rates have significantly increased, growing seven-fold during the past 20 years since it was first introduced in the late 1990s (USDA, 2023). Moreover, there are 154 known species of Brassicaceae present in South Africa that can potentially cross-fertilise with canola (Germishuizen & Meyer, 2003). As such, risks of persistence and genetic contamination need to be carefully assessed.
The application states (Section 2.4.2, p 4):
“B. napus has the ability to hybridize with related species. However, gene flow in the environment is limited by environmental barriers (pollen viability, pollen dispersal, proximity, and synchrony of flowering) and genetic barriers (ability to outcross and produce fertile progeny).”
Contamination is a significant risk for canola, due to its nature in forming weedy, feral populations and an ability to hybridise with wild relatives. This can lead to unintended contamination of wild plants with any intended and unintended genetic changes present in GM varieties (see Munier et al., 2012). Moreover, canola seeds are capable of secondary dormancy in soil, which can persist for many years. As a result, seeds may easily establish themselves in the event of seed dispersal beyond the trial site and provide a long-term source of engineered genetic material that may lead to genetic contamination
Unintended GM canola persistence has been documented in several countries as a result of field trials and seed spillage, e.g., Tasmania field trials in the 1990s led to long-term contamination that was detectable two decades later, despite efforts to exterminate the trial crops (IRDCP 2020; Sohn et al., 2021). Feral populations have been detected growing along Californian roadsides, resulting from the transportation of GM seeds to a 2007 field trial site (Munier et al., 2012) This dispersal and persistence occurred despite management plans of
returning to the plot to control for volunteer plants the next year, and surrounding areas, though the crop was not eradicated (as of time of study publication in 2012). The study noted the risk of spread of glyphosate-tolerant crops to other farming systems, concluding that,
“Canola’s glyphosate resistance in combination with canola’s seed dormancy makes it a challenging weed for roadsides, orchards, vineyards, fallow fields, and glyphosate-resistant crop fields, or anywhere where glyphosate is an important herbicide.”
Canola pollen has also been documented to flow nearly 3km away from a source field (Rieger et al., 2002), which is far greater than the trial’s 200m isolation distance from other related crops (Brassica juncea [brown mustard] and Brassica rapa [turnip]) This raises the risk of unintended gene flow, or genetic contamination, of wild relatives that are reported in the application to be in the vicinity of the trial site.
Gene flow has indeed been widely documented between GM and non-GM varieties, including in countries that have never approved its cultivation (Sohn et al., 2021), such as Argentina. Contamination of non-GM varieties has resulted in significant economic consequences, with loss of export markets due to the farmers’ inability to cultivate organic varieties (CBAN, 2019)
Hybridisation with wild relatives has also been documented, undermining the claims in the application that environmental and genetic barriers exist In 2007, a study from Canada documented hybridisation with wild relatives in two sites of natural commercial field conditions (Warwick et al., 2008)
Further, the application states (in Section 2.4.2, p. 5) that:
“The genetic modification of inserting the gat4621 gene and the mechanism of action of its gene product in DP73496 canola is not expected to increase the risk of gene flow.”
This argument is scientifically irrelevant, as the transgene does not need to confer increased risk of gene flow for the risk of gene flow to materialise. This is clearly illustrated by the abovementioned documented widespread evidence of gene flow of transgenic material from GM canola to both conventional counterparts and other wild species relatives.
In section 2.4.5 of the application concerning potential persistence, the application states that the GM canola plant would not persist in the environment, due to the lack of survival outside of controlled agricultural settings, and further that,
“Unless the habitat is regularly disturbed or seeds are replenished from outside, canola will be displaced by other plants. ”
Moreover, in section 2.5 of the application about reproducibility, the application further states that
“feral canola plants usually are not capable of surviving outside of cultivation and without human intervention for more than a few generations”.
Both claims are disproven by the evidence of GM canola persistence, including long-term persistence, with other GM canola cases, e.g., Tasmania and Canada. They also fail to acknowledge that the universal use of glyphosate may confer a selective advantage to the GM variety.
As such, the risk assessment falls short of ensuring against well-documented risks of persistence and gene flow, falling back on old data that predates the experiences above of documented unintended seed persistence, hybridisation, and gene flow.
Herbicide-tolerant traits lead to increased use of herbicides linked to farmer illness and consumer health risks
The potential approval of another herbicide-tolerant crop risks further entrenches chemical-based agriculture on multiple levels, with serious implications for human health, particularly for farm workers, but also consumers, and the environment.
First, herbicide-tolerant crops are designed for blanket spraying of herbicides, resulting in steep increases in herbicide use in high genetically modified organism (GMO) adoption regions, e.g., Argentina and the US.
Second, the rise of herbicide-tolerant weeds, which has accelerated since the adoption of GMO crops,1 has resulted in increased use of herbicides to combat the problem. Weed resistance to glyphosate has already been documented in South Africa, with resistance to glyphosate being most common. Weed resistance is now well-established as interlinked to the use of GM crops and leads to further approvals of stacked traits when efficacy declines. Any approval of this crop is thus inviting a long-term dependency on ever-increasing numbers of herbicidetolerant traits being introduced into the environment.
Third, any unintended spread of glyphosate-tolerant canola, including into other crop farm systems such as orchards or vineyards, may compromise existing use of glyphosate and result in additional alternative, possibly more toxic herbicides needing to be applied (see Munier et al., 2012).
1 https://www.weedscience.org/Pages/SOASummary.aspx
Glyphosate is classified as a probable human carcinogen by the World Health Organisation’s cancer agency (IARC, 2017). Studies on people exposed directly to glyphosate in agricultural settings, e.g., via spraying, have revealed the health risks of herbicide-tolerant crop systems. Over 100,000 class action lawsuits have taken place in the US because of occupational exposure resulting in serious, and potentially fatal, illnesses, including non-Hodgkin lymphoma. Monsanto/Bayer have thus far been forced to pay US$11 billion in damages following civil claims in the US.2 Recently, a study has linked glyphosate spray exposure in the US to reduced perinatal health, including smaller birth weights and gestational length for pregnant mothers (Reynier & Rubin, 2025)
Pesticide exposure via food consumption (aside from exposure to pesticide sprays, e.g., in farm workers) is raising concerns among human health experts. For example, a recent study from Mexico detected glyphosate in children, including those living in urban areas (and thus potentially exposed via food consumption), which was linked to increased incidence of kidney disease (Romo-GarcĂa et al., 2025) Glyphosate has also been linked to reproductive and developmental toxicity (Paganelli et al., 2010), and has been shown to have a causative effect on liver disease development at legally permitted levels for human exposure (Mesnage et al., 2015). Indeed, increases in the incidence of birth defects and reproductive problems have been linked to GM crop cultivation in Argentina (Avila-Vazquez et al., 2018).
Glyphosate has also been shown to have wide-ranging impacts on non-target organisms, including insects, pollinators, soil microorganisms, mammals, and aquatic organisms.3 Moreover, diseases have been documented in livestock fed on GM crop diets.
For all the reasons posited in this objection, we ask the Executive Council, GMO Act, to reject the application for field trials, based on the precautionary principle.
2 https://www.lawsuit-information-center.com/rounduplawsuit.html#:~:text=As%20of%20May%202025%2C%20Monsanto,trial%20resolutions%20in%20individual%20cases
3 https://www.i-sis.org.uk/Ban_GMOs_Now.pdf
References
Avila-Vazquez, M., Difilippo, F. S., Lean, B. M., Maturano, E., & Etchegoyen, A. (2018).
Environmental Exposure to Glyphosate and Reproductive Health Impacts in Agricultural Population of Argentina. Journal of Environmental Protection, 09(03), 241–253. https://doi.org/10.4236/jep.2018.93016
Canadian Biotechnology Action Network (CBAN). (2019). GM Contamination in Canada: The failure to contain living modified organisms – Incidents and impacts. https://cban.ca/wp-content/uploads/GM-contamination-in-canada-2019.pdf
Germishuizen, G., & Meyer, N. L. (Eds.). (2003). Plants of southern Africa: An annotated checklist. National Botanical Institute.
IARC. (2017). ARC Monographs on the evaluation of carcinogenic risks to humans Volume 112: Some organophosphate insecticides and herbicides. https://monographs.iarc.fr/wp-content/uploads/2018/07/mono112.pdf
International Research & Development Center for Publication (IRDCP). (2020). Proceedings: International Conference on Agriculture, Environmental and Rural Development (1st ed.). https://doi.org/10.22161/conf.aerd.2020
Mesnage, R., Arno, M., Costanzo, M., Malatesta, M., SĂ©ralini, G.-E., & Antoniou, M. N. (2015). Transcriptome profile analysis reflects rat liver and kidney damage following chronic ultra-low dose Roundup exposure. Environmental Health, 14(1), 70. https://doi.org/10.1186/s12940-015-0056-1
Munier, D. J., Brittan, K. L., & Lanini, W. T. (2012). Seed bank persistence of genetically modified canola in California. Environmental Science and Pollution Research, 19(6), 2281–2284. https://doi.org/10.1007/s11356-011-0733-8
Paganelli, A., Gnazzo, V., Acosta, H., López, S. L., & Carrasco, A. E. (2010). Glyphosate-Based Herbicides Produce Teratogenic Effects on Vertebrates by Impairing Retinoic Acid Signaling. Chemical Research in Toxicology, 23(10), 1586–1595. https://doi.org/10.1021/tx1001749
Reynier, E., & Rubin, E. (2025). Glyphosate exposure and GM seed rollout unequally reduced perinatal health. Proceedings of the National Academy of Sciences, 122(3), e2413013121. https://doi.org/10.1073/pnas.2413013121
Rieger, M. A., Lamond, M., Preston, C., Powles, S. B., & Roush, R. T. (2002). Pollen-Mediated Movement of Herbicide Resistance Between Commercial Canola Fields. Science, 296(5577), 2386–2388. https://doi.org/10.1126/science.1071682
Romo-GarcĂa, M. F., Mendoza-Cano, O., Murillo-Zamora, E., Camacho-de la Cruz, A. A., RĂosSilva, M., Bricio-Barrios, J. A., Cuevas-Arellano, H. B., Rivas-Santiago, B., MaedaGutiĂ©rrez, V., Galván-Tejada, C. E., & Gonzalez-Curiel, I. E. (2025). Glyphosate exposure increases early kidney injury biomarker KIM-1 in the pediatric population: A crosssectional study. Science of The Total Environment, 980, 179533. https://doi.org/10.1016/j.scitotenv.2025.179533
Sohn, S.-I., Pandian, S., Oh, Y.-J., Kang, H.-J., Ryu, T.-H., Cho, W.-S., Shin, E.-K., & Shin, K.-S. (2021). A Review of the Unintentional Release of Feral Genetically Modified Rapeseed into the Environment. Biology, 10(12), 1264. https://doi.org/10.3390/biology10121264
USDA. (2023). Report Name: Surging Rapeseed Production. (SF2023-0024). United States Department of Agriculture.
https://apps.fas.usda.gov/newgainapi/api/Report/DownloadReportByFileName?fileNa me=Surging%20Rapeseed%20Production_Pretoria_South%20Africa%20%20Republic%20of_SF2023-0024.pdf
Warwick, S. I., Légère, A., Simard, M. J. & James, T. (2008). Do escaped transgenes persist in nature? The case of an herbicide resistance transgene in a weedy Brassica rapa population. Molecular Ecology, 17(5), 1387–1395. https://doi.org/10.1111/j.1365294X.2007.03567.x
