Thursday, January 1, 2015

Round Up "Guess"-timating glyphosate


 New math 


Dr. Kevin Folta, chairman of the horticulture department at University of Florida wrote a blog post titled "Inconvenient Glyphosate Math" linked above in the title, but his new math muddies the facts on glyphosate instead of illuminating them.It represents the pacifying, complacent extreme on medical relevance of glyphosate- and some might say, my blog post will present the opposite, the precautionary principled extreme.

I was prompted to write this because an alarming study was recently published reporting  glyphosate leads to proliferation of a type of breast cancer cells- sensitive to estrogen & progesterone. Common sense suggests that a prevalent chemical stimulating growth of breast cancer in trace amounts surely should be monitored. Unfortunately, as you will see, our regualtory agencies tasked with protecting public health have never monitored glyphosate and still do not.

Please watch video



Glyphosate is an active ingredient of the most widely used herbicide and it is believed to be less toxic than other pesticides. However, several recent studies showed its potential adverse health effects to humans as it may be an endocrine disruptor. This study focuses on the effects of pure glyphosate on estrogen receptors (ERs) mediated transcriptional activity and their expressions. Glyphosate exerted proliferative effects only in human hormone-dependent breast cancer, T47D cells, but not in hormone-independent breast cancer, MDA-MB231 cells, at 10⁻¹² to 10⁻⁶M in estrogen withdrawal condition. The proliferative concentrations of glyphosate that induced the activation of estrogen response element (ERE) transcription activity were 5-13 fold of control in T47D-KBluc cells and this activation was inhibited by an estrogen antagonist, ICI 182780, indicating that the estrogenic activity of glyphosate was mediated via ERs. Furthermore, glyphosate also altered both ERα and β expression. These results indicated that low and environmentally relevant concentrations of glyphosate possessed estrogenic activity. Glyphosate-based herbicides are widely used for soybean cultivation, and our results also found that there was an additive estrogenic effect between glyphosate and genistein, a phytoestrogen in soybeans. However, these additive effects of glyphosate contamination in soybeans need further animal study.

Previous studies have already suggested it acts as an  endocrine disruptor affecting aromatase.  This of course is in addition to many other studies demonstrative of pathological changes  including teratogenecity via the retinoic acid pathway, as well as uncoupling of oxidative phosphorylation potentiated by glyphosate's adjuvants,  associated with liver damage among other disorders.  Unfortunately toxicity of these undisclosed inactive ingredients isn't evaluated in toxicity studies, even though they are very active!

More information on glyphosate here

Neither the FDA nor the USDA have ever measured glyphosate residues in food in spite of the fact that use of glyphosate has skyrocketed with evolution of superweeds, making it the most prevalent chemical in agriculture.

So, I was curious what the residues of glyphosate in food might be. 


Lets do some back of the cocktail napkin math

  • Labeling instruction are 22-64 oz/acre / season depending on weed pressure.

  • A liter of glyphosate formula contains 560gm of glyphosate (plus adjuvants potentiating toxicity)

  • 22oz/acre=0.66L x 560gm/ L= 369.6gm/ acre  -to-   64oz/acre=1.92L x 560gm/L= 1075gm/ acre.

  • Average soybean yield / acre=2580lb~1170kg

  • 369.6gm/1170kg soybeans=0.316gm (316mg)- to- 1075gm/1170kg soybeans=0.920gm (920mg)

Thus it appears glyphosate residues could potentially range between 0.316 gm to as high as ~0.92gm/ kg of sprayed  soybean- that is  316mg to 920mg per kg of soybeans 

if maximum per label amount of 64oz/acre are used preharvest as a dessicant
- which hopefully they aren't. 

Of course this amount isn't found in the soybeans themselves- glyphosate translocates through the plant but  100% of it certainly doesn't end up in the seed. Some of the glyphosate  is sprayed on weeds and since seed planting density varies from farmer to farmer we have no way of figuring out how much actually ends up on soybean plants.  Residues decay after glyphosate is sprayed and thus are highly dependent on the period it is applied preceding harvest, but Monsanto reports seed residues at 110 days post spraying, while the label authorizes  its use just one week before harvest as a dessicant, which is a serious concern!

This is about 100 times more than the residues a recent study reported in a few market samples of Iowa soybeans - 9mg/kg ( glyphosate + AMPA combined).

 I am not sure where my math might have gone wrong.  Or has it? In a worst case scenario?  
How do we know actual residues on GMO crops- if we don't measure them?

The answer is: WE DON'T!

We do know this though: glyphosate stimulates breast cancer in parts/trillion--thousands of times less than even the smallest measured concentrations. And we know undoubtedly that the cancer experts at the World Health Organization just classified it as a probable carcinogen (Class 2A). 

 Is this  back-o'-the-cocktail- napkin analysis ..... a glorified~sorta~educated guess...sufficient to protect public health? Of course not! Just look at the difference between Dr. Folta's guesstimate and mine.

WE need to measure glyphosate residues in food and even more importantly in animals and people. There are multiple non-dietary exposure pathways so ingestion of food is itself only a partial measure of exposure. Here are some neat maps that show how variable glyphosate is in water & how much the use has escalated over time- since introduction of genetically modified (GMO) crops in 1995 

 However in the meantime, we should apply the Precautionary Principle:

When an activity raises threats of harm to the environment or human health, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically.

All statements of the Precautionary Principle contain a version of this formula: When the health of humans and the environment is at stake, it may not be necessary to wait for scientific certainty to take protective action. 

Q. Is there some special meaning for "precaution"?

A. It's the common sense idea behind many adages: "Be careful." "Better safe than sorry." "Look before you leap." "First do no harm."

The Precautionary principle is discussed in 13 international treaties < Please download the PDF  Excerpt Despite its presence in a growing body of EU and national legislation and case law, the application of the precautionary principle has been strongly opposed by vested interests who perceive short term economic costs from its use. There is also intellectual resistance from scientists who fail to acknowledge that scientific ignorance and uncertainty, are excessively attached to conventional scientific paradigms, and who wait for very high strengths of evidence before accepting causal links between exposure to stressors and harm. The chapter focuses on some of the key issues that are relevant to a more common understanding of the precautionary principle and to its wider application. These include different and confusing definitions of the precautionary principle and of related concepts such as prevention, risk, uncertainty, variability and ignorance; common myths about the meaning of the precautionary principle; different approaches to the handling of scientific complexity and uncertainty; and the use of different strengths of evidence for different purposes. The context for applying the precautionary principle also involves considering the 'knowledge to ignorance' ratio for the agent in focus: the precautionary principle is particularly relevant where the ratio of knowledge to ignorance is low, as with emerging technologies.

 Until glyphosate residues are assayed and reported by the USDA or FDA -and why the hell aren't they?* -- stay away from genetically modified (GMO) soybean products!

* Anonymous spokesperson at USDA says that it is too expensive to measure glyphosate. Question is: too expensive for who? FDA & USDA can't afford liquid chromatography in tandem with MS, that just about every university has? Hmmmmm. Clearly the $8,000,000,000/ annual herbicide sales have not influenced that decision.