According to a new study in the magazine FoodConventional farmers now use twice as much glyphosate spray as the late 1990s when genetically modified plants became popular, mainly because weeds have developed resistance to glyphosate over time. As a result, the glyphosate residues in plant plant tissue also increase. New research suggests that these residues can be harmful to animals that eat the contaminated plants. Thanks to genetic engineering, which is prohibited in the production of organically certified plants, plants such as corn and soybeans can tolerate herbicides such as glyphosate. These herbicides typically kill crops when sprayed, but herbicide tolerance allows weeds within crop fields to be controlled by using sprays instead of holistic or mechanical practices used in organic farming. Genetically modified, glyphosate-tolerant (GT) soybeans dominate the global production of soy, which is mainly used for animal feed.
This study shows that the amount of glyphosate typically sprayed in commercial production is much higher than the amount used in field trials by companies for which the safety of glyphosate has been determined. As a result, the backlog found in field trials by companies is much less concentrated than in factories in the United States and the two largest soybean producing countries, Brazil and Argentina. In fact, the backlogs from South American countries were up to 78 times higher than those reported in companies' field trials and more than twice the backlog limit imposed by the European Union. The U.S. border is twice that of the EU, and even samples from Argentina have exceeded U.S. tolerance for glyphosate residues. This finding is critical, since only data from company field trials are required for the risk assessment of glyphosate. If these studies are not common practice worldwide, the safety of glyphosate is overestimated.
The study also examined whether the residue levels found in soybeans from actual farms could affect the health of the animals that eat them. The researchers reviewed studies comparing the health and survival of aquatic invertebrates that were fed GT soy to certified organic soy and found that animals that ate the organic feed had a higher survival rate and reproduced faster. When the invertebrates received higher doses (up to those found on farms in Iowa), their survival and height were reduced and it took longer to reach maturity. While the organisms tested are smaller than humans, the significant health effects suggest that more safety tests should be done at concentrations found in actual factories rather than the much lower concentrations reported by industry. This study also shows that eating organic soybeans can help you avoid the risks associated with glyphosate, which is prohibited for organic production.