6.4—GM crops have fewer toxins than non-GM crops

GM crops do not accumulate environmental toxins or concentrate toxins in animals that eat them

See Genetic Roulette’s False Claims at Bottom of Page

Analysis of Peer-Reviewed Research:

The evidence on which Jeffrey Smith bases in his claims in this section is so insubstantial that it is not worthy of detailed analysis except to point out briefly where it is misleading and inadequate .

We have already mentioned that his earlier claims that herbicide residues are increased in genetically modified crops are not backed up by any measurements of herbicide residue levels. He repeats those claims without any further evidence on this section. GM technology actually promotes a switch to less use of herbicides, and a switch to herbicides that are less persistent and less hazardous (Brooks and Barfoot 2007). He then goes on to mention a report from Beijing about low levels of heavy metals being present in vegetable oils sold in Beijing markets. Astonishingly he believes this indicates that GM crops can actively concentrate heavy metals. One wonders if Smith had been confronted with some link to genetic manipulation in the more recent Chinese scandal of melamine contamination of milk products (USA Today 2008) he would have claimed that genetic engineering causes cows to bioaccumulate melamine. Presence of trace levels of pollutants in Chinese produce is more realistically an indicator of pollution and poor food standards in China rather being caused by genetic engineering. The study he quoted provides no evidence that GM crops bioaccumulate heavy metals.

Jeffrey Smith then goes on to quote some documents from the FDA Centre of Veterinary Medicine which provide no tangible support for his claims. One can only assume that Smith assumes that readers will be too lazy to check documents to see what they say. Next he comments about Bt toxins accumulating in a food chain with evidence that again, given any sort of close scrutiny and reflective thinking, is irrelevant to the argument that he is mounting. Finally he continues to assert that glyphosate herbicide will be bioaccumulated. The published safety assessments that have been performed on glyphosate demonstrate this does not happen. At least he grudgingly admits the existence of this counter evidence (Williams and others 2000).


Brookes G, Barfoot P (2007). Global impact of biotech crops: Socio-economic and environmental effects, 1996-2006. AgBioForum, 11: 21-38. Available on the World Wide Web: www.agbioforum.org.

USA Today (2008). Tainted milk sickens more than 1,200 babies in China USA Today 9/15/2008 www.usatoday.com/news/health/2008-09-15-baby-formula_N.htm accessed Jan 16 2009.

Williams GM, Kroes R, Munro IC. (2000). Safety evaluation and risk assessment of the herbicide Roundup and its active ingredient, glyphosate, for human. Regul Toxicol Pharmacol 31:117–165.

“The oral absorption of glyphosate and AMPA is low, and both materials are eliminated essentially unmetabolized. Dermal penetration studies with Roundup showed very low absorption. Experimental evidence has shown that neither glyphosate nor AMPA bioaccumulates in any animal tissue. No significant toxicity occurred in acute, subchronic, and chronic studies.”

Genetic Roulette Falsely Claims:
GM crops may accumulate environmental toxins or concentrate toxins in milk and meat of GM-fed animals.

1. FDA scientists warned that GM crops may concentrate toxins, such as heavy metals and herbicides, from the environment.

2. There is evidence of heavy metals in GM soya bean oil.

3. FDA scientists also said that toxins in GM food might concentrate in milk or meat.

4. GM DNA fragments were found in milk.

5. While very little research has been done on this, small amounts of Roundup may be retained in the body of animals and affect sperm quality.

6. The overuse of Roundup and Liberty herbicide in GM crops magnifies these types of risks.

Genetic Roulette speculates that GM crops may accumulate environmental toxins and cause accumulation of toxins in animal products that are eaten.

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