Glyphosate binds (chelates) vital nutrients such as iron, manganese, zinc, and boron in the soil, preventing plants from taking them up. This could also have implications for humans and animals that eat GM glyphosate-tolerant crops, as it could affect nutrient value.
Glyphosate binds (chelates) vital nutrients such as iron, manganese, zinc, and boron in the soil, preventing plants from taking them up.1 2 3 4 So GM soy plants treated with glyphosate have lower levels of essential nutrients and reduced growth, compared with GM and non-GM soy controls not treated with glyphosate.5 6 Lower nutrient uptake may partly account for the increased susceptibility of GM soy to disease,7 as well as its lower yield.8 It could also have implications for humans and animals that eat the crop, as it could affect nutrient value.
A German-Egyptian team of researchers found that all cows tested from Danish dairy farms excreted glyphosate in their urine. Unexpectedly low levels of manganese and cobalt were observed in all animals, which the authors said could be explained due to the strong metal chelating effect of glyphosate. Potential signs of liver and kidney toxicity were also found in the cows, which the authors noted were consistent with the findings of rodent feeding studies with GM glyphosate-tolerant plants.9
- Cakmak I, Yazici A, Tutus Y, Ozturk L. Glyphosate reduced seed and leaf concentrations of calcium, manganese, magnesium, and iron in non-glyphosate resistant soybean. Eur J Agron. 2009;31:114–119.
- Neumann G, Kohls S, Landsberg E, Stock-Oliveira Souza K, Yamada T, Romheld V. Relevance of glyphosate transfer to non-target plants via the rhizosphere. J Plant Dis Prot. 2006;20:963–969.
- Huber DM. What about glyphosate-induced manganese deficiency? Fluid J. 2007:20–22.
- Bott S, Tesfamariam T, Candan H, Cakmak I, Römheld V, Neumann G. Glyphosate-induced impairment of plant growth and micronutrient status in glyphosate-resistant soybean (Glycine max L.). Plant Soil. 2008;312(1-2):185-194. doi:10.1007/s11104-008-9760-8.
- Zobiole LH, de Oliveira RS, Visentainer JV, Kremer RJ, Bellaloui N, Yamada T. Glyphosate affects seed composition in glyphosate-resistant soybean. J Agric Food Chem. 2010;58:4517-22. doi:10.1021/jf904342t.
- Zobiole LHS, de Oliveira RS, Huber DM, et al. Glyphosate reduces shoot concentrations of mineral nutrients in glyphosate-resistant soybeans. Plant Soil. 2010;328:57–69.
- Kremer RJ. Glyphosate affects soybean root exudation and rhizosphere microorganisms. Int J Anal Environ Chem. 2005;85:1165–1174.
- Johal GS. Glyphosate effects on diseases of plants. Eur J Agron. 2009;31:144–152.
- Krüger M, Schrödl W, Neuhaus J, Shehata AA. Field investigations of glyphosate in urine of Danish dairy cows. J Env Anal Toxicol. 2013;3(5). doi: http://dx.doi.org/10.4172/2161-0525.1000186.