Glyphosate in our Food II: Highest Levels in Legumes & Cereals because of Farming “Dry-Down”

For those concerned about pesticides in our foods, the link between harvesting practices and staggering high levels of glyphosate in common “healthy” cereals and legumes may come as a shock.  Glyphosate, the active chemical in Roundup® and other pesticides, is considered to be “probably carcinogenic to humans”[i], a cause of non-hodgkins lymphoma, toxic to aquatic life,[ii] and a cause of milkweed decline.[iii]

High levels of glyphosate are present in many common foods, but so high in cereals and legumes that Canada’s legal limits are exceeded, as revealed by data from the Canadian Food Inspection Agency (CFIA) and other data[iv]. The CFIA data[v] revealed violations of Canada’s maximum residue limits in 26 out of 71 samples of chickpeas sampled (36.6%), and 2 out of 55 wheat bran samples. There were also violations for kidney bean, rye grain and products, bean flour, chickpea products and flour, and millet. Glyphosate was detected in 36.6% of grain products, 47.4% of bean/pea/lentil products, and 31.7% and 30.7% of infant cereal and food, respectively.[vi]

It appears these high levels result from a farming technique called “desiccation” or “drying down”, intended for crops that ripen unevenly or contain green material. The chemical is sprayed right on to the crops, while they are still growing in the field, in order to deliberately kill them at a targeted time and allow for a planned harvest. Glyphosate, a “systemic” chemical, gets rights into the circulation system of the plant and moves to the points of sugar delivery. These points are called “sinks”; they are typically roots, young shoots and developing seeds. For cereals and legumes, the “sinks” are the developing seeds, which is what we eat.

There is no way to know what specific crops have been desiccated with glyphosate, because farming techniques are not monitored.[vii] There is also no way to know when the crops are sprayed.  Timing is important: authorities say that if spraying occurs when there is more than 30% moisture content in the crop, then more glyphosate ends up in the seed sink. The practise guideline for determining the “stage of growth” is a “thumbnail test” and “visual colour test”[viii]. These guidelines are problematic, especially with indeterminate crops like beans that don’t stop producing seeds, because their seeds don’t mature all at the same time.

Safe Food Matters recently objected to the 2017 re-registration of glyphosate in Canada on the basis of this desiccation issue, among other things.  Glyphosate has been in commercial use in Canada since 1994, and was re-registered in 2017, following a re-evaluation process that is required by law[ix] every 15 years. The most recent process started in 2009 and took 8 years. A summary of the arguments set out in the Notice of Objection can be viewed here [link pending].
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[i] World Health Organization, International Agency for Research on Cancer. (March 2, 2015). IARC Monographs Volume 112: evaluation of five organophosphate insecticides and herbicides at 1 online https://www.iarc.fr/en/media-centre/iarcnews/pdf/MonographVolume112.pdf 
[ii] Canadian Association of Physicians for the Environment and Equiterre, “Backgrounder: Glyphosate: Ubiquitous and Worrisome” (2017), online https://cape.ca/wp-content/uploads/2016/05/Glyphosate-Bckgd-ENG-2016.pdf
[iii] Zaya, D. N., Pearse, I. S., & Spyreas, G, “Long-term trends in Midwestern milkweed abundances and their relevance to monarch butterfly declines” (2017)  67(4) Bioscience 343-356

[iv] Academic studies report glyphosate concentrations in wheat seed, red lentils, dry beans and field peas that exceed the legal limits of Canada or other countries. Studies also report high levels in spring wheat, barley, flax, canola, and lentils.
[v] As reported by Tony Mitra in “Glyphosate in chickpea, lentil and wheat bran” (June 15, 2017), online  http://www.tonu.org/2017/06/15/glyphosate-in-chickpea-lentil-and-wheat-bran/
[vi] Canadian Food Inspection Agency. (2017) Safeguarding with Science: Glyphosate Testing in 2015-2016 at 4 online at http://www.inspection.gc.ca/DAM/DAM-food-aliments/STAGING/text-texte/chem_testing_report_2015-2016_glyphosate_srvy_rprt_1491855525292_eng.pdf
[vii] In Canada, companies have registered glyphosate for use as a desiccant on wheat, barley, oats, canola, flax, lentils, peas, drybeans and soybeans. The Pest Management Regulatory Agency has also permitted it to be used on the additional crops of chickpeas, lupin, faba bean, canaryseed, camelina, mustard and forage[vii], even though no company has registered it for such use.  (Saskatchewan Ministry of Agriculture. (2017). 2017 Guide to Crop Protection at 235). Such use  is permitted under the User Requested Minor Use Label Expansion program.

[viii] Monsanto Company, Roundup Preharvest Staging Guide, 4 online at http://www.roundup.ca/_uploads/documents/MON-Preharvest Staging Guide.pdf
[ix] Pest Control Products Act, S.C.2002, c.28 sec 16(1).