GMO's, Herbicides, and Public Health

[Beorn]

I'm not sure pro-GMO folks have paid enough attention to the issues related to the increased use of herbicides (poison) on GMO crops.

Perspective
GMOs, Herbicides, and Public Health

Philip J. Landrigan, M.D., and Charles Benbrook, Ph.D.

...
But widespread adoption of herbicide-resistant crops has led to overreliance on herbicides and, in particular, on glyphosate.5 In the United States, glyphosate use has increased by a factor of more than 250 — from 0.4 million kg in 1974 to 113 million kg in 2014. Global use has increased by a factor of more than 10. Not surprisingly, glyphosate-resistant weeds have emerged and are found today on nearly 100 million acres in 36 states. Fields must be now be treated with multiple herbicides, including 2,4-D, a component of the Agent Orange defoliant used in the Vietnam War.

The first of the two developments that raise fresh concerns about the safety of GM crops is a 2014 decision by the Environmental Protection Agency (EPA) to approve Enlist Duo, a new combination herbicide comprising glyphosate plus 2,4-D. Enlist Duo was formulated to combat herbicide resistance. It will be marketed in tandem with newly approved seeds genetically engineered to resist glyphosate, 2,4-D, and multiple other herbicides. The EPA anticipates that a 3-to-7-fold increase in 2,4-D use will result.

In our view, the science and the risk assessment supporting the Enlist Duo decision are flawed. The science consisted solely of toxicologic studies commissioned by the herbicide manufacturers in the 1980s and 1990s and never published, not an uncommon practice in U.S. pesticide regulation. These studies predated current knowledge of low-dose, endocrine-mediated, and epigenetic effects and were not designed to detect them. The risk assessment gave little consideration to potential health effects in infants and children, thus contravening federal pesticide law. It failed to consider ecologic impact, such as effects on the monarch butterfly and other pollinators. It considered only pure glyphosate, despite studies showing that formulated glyphosate that contains surfactants and adjuvants is more toxic than the pure compound.

The second new development is the determination by the IARC in 2015 that glyphosate is a “probable human carcinogen”1 and 2,4-D a “possible human carcinogen.”2 These classifications were based on comprehensive assessments of the toxicologic and epidemiologic literature that linked both herbicides to dose-related increases in malignant tumors at multiple anatomical sites in animals and linked glyphosate to an increased incidence of non-Hodgkin's lymphoma in humans.
...

The New England Journal of Medicine: GMOs, Herbicides, and Public Health

 

[á´…eparted]

This was actually brought up by a friend of mine last week. She's about to get her B.S. in environmental engineering and her research is in this area. It was the first I've heard of it from a credible person. We had a decent discussion about it, and it was the first time I heard a reasonable argument against GMO's. While I agree with her that it's a problem, I disagree with her on the solution. Her and other environmentalists feel this is grounds to restrict or reduce GMO's. I think the solution is to invest in new generations of more effective and selective pesticicdes. It's a problem that needs to be solved anyway, and there is a heightened level of urgency due to GMO's now. Further, it's a solveable problem, and I can say that with high confidance since that is within my field.

 

[Beorn]

This was actually brought up by a friend of mine last week. She's about to get her B.S. in environmental engineering and her research is in this area. It was the first I've heard of it from a credible person. We had a decent discussion about it, and it was the first time I heard a reasonable argument against GMO's. While I agree with her that it's a problem, I disagree with her on the solution. Her and other environmentalists feel this is grounds to restrict or reduce GMO's. I think the solution is to invest in new generations of more effective and selective pesticicdes. It's a problem that needs to be solved anyway, and there is a heightened level of urgency due to GMO's now. Further, it's a solveable problem, and I can say that with high confidance since that is within my field.

So what are the barriers to the solution?
Is it merely money?

 

[á´…eparted]

So what are the barriers to the solution?
Is it merely money?

It is not money. It takes a lot of time and effort to develop new compounds. I suspect the answer towards truly novel and selective herbicides will be of a chemical biology solution (short peptides, or proteins), but that has a delivery problem which is a bit beyond what I could solve.

In order to develop new compounds for any biological application, you have to know what your aiming for. It's usually a single, or several receptors on proteins found in a given organism. That's all well and good but you also have to know something about the shape of the receptor (something that is not trivial to figure out), and deduce what kinds of compounds will fit in there. Then there is the design process. How do you make these compounds? It's solvable, but it can take years depending on how complex the molecule is. In industry, it's common practice to screen (meaning test) hundereds of compounds, all of which have to be made, and see how they effect the organism. Then, pick the best hits and further attempt to improve them. They also need to be tested on other organisms to see what it effects in those cases. Nearly all compounds get rejected for one reason or another.

One of the current problems with herbacides, is they're broad spectrum. They're toxins that target common biological pathways in many plants and kills them. The reason this is done is it's much easier, cheaper, and effective. Individual targets will likely cost quite a bit more, but it's surmountable. Scientists are going to have to rigorously analyze plants and look for unique metabolics pathways for individual plants, then select for the pathways that are fatal if blocked. This is no easy task, but a task that can be done with time.