1.3.2022
EN
Official Journal of the European Union
C 99/69 Wednesday 7 July 2021
Outstanding questions concerning Bt toxins
H. whereas toxicological tests for GM authorisations are carried out with isolated Bt toxins; whereas little significance can be attributed to toxicological tests conducted with proteins in isolation due to the fact that Bt toxins in GM crops, such as maize, cotton and soybeans, are inherently more toxic than isolated Bt toxins; whereas this is because protease inhibitors (PI), present in the plant tissue, can increase the toxicity of the Bt toxins by delaying their degradation; whereas this phenomena has been demonstrated in a number of scientific studies, including one conducted for Monsanto 30 years ago which showed that even the presence of extremely low levels of PI enhanced the toxicity of Bt toxins up to 20-fold (11);
I. whereas those effects are not taken into account in EFSA risk assessments, even though they are relevant for all Bt plants approved for import or cultivation in the Union; whereas risks, arising from this enhanced toxicity due to the interaction between PI and Bt toxins, to humans and animals consuming food and feed containing Bt toxins cannot be ruled out;
J. whereas a number of studies show that side effects have been observed that may affect the immune system following exposure to Bt toxins and that some Bt toxins may have adjuvant properties (12), meaning that they can increase the allergenicity of other proteins with which they come into contact;
K. whereas assessment of the potential interaction of herbicide residues and their metabolites with Bt toxins is considered outside the remit of the EFSA GMO Panel and is therefore not undertaken as part of the risk assessment; whereas this is problematic since residues from spraying with glufosinate are known to disturb the microbiome which, for example, may enhance immune reactions in combination with Bt toxins (13);
Bt crops: effects on non-target organisms and increased resistance
L. whereas, unlike the use of insecticides, where exposure is at the time of spraying and for a limited time afterwards, the use of Bt GM crops leads to continuous exposure of the target and non-target organisms to Bt toxins;
M. whereas the assumption that Bt toxins exhibit a single target-specific mode-of-action can no longer be considered correct and effects on non-target organisms cannot be excluded (14) whereas an increasing number of non-target organisms are reported to be affected in many ways; whereas 39 peer-reviewed publications that report significant adverse effects of Bt toxins on many ‘out-of-range’ species are mentioned in a recent overview (15); whereas a range of non-target organisms in the Union could be exposed to Bt toxins via spillage, waste and manure resulting from the import of Bt crops; whereas no effects on non-target organisms were evaluated in the risk assessment;
N. whereas the risk assessment did not consider the development of resistance in the target pests to Bt toxins, possibly resulting in the use of less environmentally safe pesticides or increased doses and the number of applications to the GM crop in the country of cultivation; whereas, the United States Environmental Protection Agency is planning to phase out many Bt corn hybrids, as well as some Bt cotton varieties, in the next three to five years, due to the growth in insect resistance to such crops (16);
(11) (12) (13) (14) (15) (16)
MacIntosh, S.C., Kishore, G.M., Perlak, F.J., Marrone, P.G., Stone, T.B., Sims, S.R., Fuchs, R.L., ‘Potentiation of Bacillus thuringiensis insecticidal activity by serine protease inhibitors’, Journal of Agricultural and Food Chemistry, 38, pp. 1145-1152, https://pubs. acs.org/doi/abs/10.1021/jf00094a051 For a review, see Rubio-Infante, N., Moreno-Fierros, L., ‘An overview of the safety and biological effects of Bacillus thuringiensis Cry toxins in mammals’, Journal of Applied Toxicology, May 2016, 36(5), pp. 630 648, https://onlinelibrary.wiley.com/ doi/full/10.1002/jat.3252 Parenti, M.D., Santoro, A., Del Rio, A., Franceschi, C., ‘Literature review in support of adjuvanticity/immunogenicity assessment of proteins’, EFSA Supporting Publications, January 2019, 16(1): 1551, https://efsa.onlinelibrary.wiley.com/doi/abs/10.2903/ sp. efsa.2019.EN-1551 See, for example, Hilbeck, A., Otto, M., ‘Specificity and combinatorial effects of Bacillus thuringiensis Cry toxins in the context of GMO environmental risk assessment’, Frontiers in Environmental Science 2015, 3:71, https://doi.org/10.3389/fenvs.2015.00071 Hilbeck, A., Defarge, N., Lebrecht, T., Bøhn, T., ‘Insecticidal Bt crops.
EFSA’s risk assessment approach for GM Bt plants fails by design’, RAGES 2020, p. 4, https://www.testbiotech.org/sites/default/files/RAGES_report-Insecticidal %20Bt%20plants.pdf https://www.dtnpf.com/agriculture/web/ag/crops/article/2020/09/29/epa-proposes-phasing-dozens-bt-corn