QHow much pesticide and / or weed killer gets absorbed into freshly planted GM seeds from residual amounts in the soil from previous treatments ? And how much gets absorbed by plants through roots after new treatments ? And, do end products retain any pest

How much pesticide and / or weed killer gets absorbed into freshly planted GM seeds from residual amounts in the soil from previous treatments ? And how much gets absorbed by plants through roots after new treatments ? And, do end products retain any pesticide or weed killer amounts (other than washable surface amounts) that would be unsafe to humans ? Who determines safe levels if any levels do in fact exist ? And finally, are different amounts absorbed by non-GM originated plants ?

AExpert Answer

Your questions all relate to the safety of pesticide residues that may occur in GM crops. 

 

That’s a reasonable concern given the rapid adoption and widespread use of GM crops. Importantly, since crops tolerant to herbicides such as glyphosate are very popular among farmers, spraying of glyphosate could lead to residues of the active ingredient in the forage or grain that is consumed by animals or humans.  When farmers spray fields to eliminate weeds that compete with the crop and reduce yield, the vast majority of the glyphosate enters plants through the leaves.  Glyphosate is tightly bound to soil, and little or no glyphosate is taken up from the soil, either by newly planted seeds or by existing plants, whether GM or non-GM.  One of the reasons that glyphosate is so popular with farmers is that farmers can safely plant other crops after using glyphosate without impacts on the subsequent crop.  Over time, soil microorganisms break down any glyphosate residues in the soil.

 

Any glyphosate residues that remain in the plant decrease over time following application, and are less in grain compared to leaves.  Processing of grain for use in food also reduces detectible residues.  For example, there is no detectible glyphosate present in the oil fraction in soybean or corn oil.

 

Finally, since there is the potential for residues of glyphosate to remain in forage and grain used in animal feed and human foods, the levels must be measured across many locations and environments to determine the highest levels that might be present.  In the US, the EPA is responsible to examine all uses of pesticides and must examine the residue data and establish safe levels of exposure.  All uses must be approved and the combined exposure from all crops must be below the acceptable dose level established by the EPA.  This process was described previously in detail on this site.  That answer can be found at: (http://gmoanswers.com/ask/how-are-gmo-foods-regulated).  Other countries follow similar procedures within their regulatory agencies. 

Posted on January 31, 2018
Thank you for your question. There are various aspects of your question. I assume your question refers to the use of Agrobacterium rhizogenes by scientists to intentionally transfer genes from the bacterium to plants. Infection and DNA transfer from this bacterium occurs in nature all the time to cause disease. Such transformed plants are not classified as GMOs since transfer occurred naturally. If this is done by scientists then it would be classified as a GMO. Rules and... Read More
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Posted on March 1, 2018
I’m a Monsanto scientist who has more than 20 years of experience with genetic modification of plants. I will try to answer your question, even though I don’t ever do experiments on animals, certainly not on humans, of course! Can humans be genetically modified…but a much bigger question is should humans be genetically modified? There are two ways to think about genetic modification of humans (or any animal). One way is modification of somatic cells, and the other is the... Read More
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Posted on May 10, 2017
The simple answer is that 20+ years of composition assessments of GMO crops have demonstrated that crop composition is not appreciably affected by the GM process (1). In addition, data collected through that time have indicated that general factors such as the growth environment can contribute to notable variation in component levels (2). Plant agglutinins (or lectins) and amylase inhibitors are examples of anti-nutritional compounds that may be present in crops. The relevance of such a... Read More

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