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Ending glyphosate is a virtuous goal, and reducing pesticides is essential

A new Parliamentary Petition to ban glyphosate and to reduce pesticide use in Canada is worthy of support. Substantial pesticides reduction and alternative strategies for growing are essential, for healthy environments, food and people, to support biodiversity and to avoid regrettable substitutes for glyphosate .

Indeed, a stated goal of the UN Biodiversity Conference (COP-15), in Montreal this December, is to reduce pesticides by two thirds.

Glyphosate is by far the most-used pesticide in Canada

Health Canada’s pesticides sales reports have a special category for glyphosate—more than 25 million kilograms per year, in every report on record. “More than” tells us little about how much is actually sold, but for comparison a lot more glyphosate is sold than chlorine bleach, in a lower sales category.

Where is glyphosate?

Internationally, glyphosate use skyrocketed from 1974 to 2014, with a majority used on genetically modified crops. Canada has no systematic data collection to track what pesticides have been used where; therefore it is a major research project to calculate estimates.

The government recently allocated funding measurement of pesticides in surface water, but Canada doesn’t routinely track details of pesticides use, or contamination in drinking water and food, the environment, or the human population.

We don’t know how much glyphosate is in Canadian residents. After years of promises, glyphosate is still slated to be measured in a sample of Canadians, in “the next” population biomonitoring cycle of the Canadian Health Measures Survey.

Most Americans have glyphosate in their bodies

In June 2022, the US Centers for Disease Control and Prevention (CDC) reported analyses of urine samples gathered from US residents 6 years of age and older, in 2013-2014. Of 2310 samples, 82% were at or above the detection limit.

Analysis of bio-banked samples is an option that Canada could consider.

Agriculture must become more sustainable with fewer inputs.

If the focus is solely to eliminate glyphosate, it might just be replaced with herbicides—old or new—that are worse. The solution is a transition to ecologically based, organic, regenerative growing.

A large international study published in September 2022 states, “Ecological intensification could help return agriculture into a “safe operating space” for humanity.” Regenerative, organic methods can reduce inputs, improve production and profits, and improve climate resilience.

Long-standing agricultural herbicides

Phenoxys

Old-time herbicides such as 2,4-D, mecoprop and dicamba, along with their carcinogenic dioxin contaminants, are still registered in Canada, and they could well make a come-back. Indeed, they are already being mixed with glyphosate in order to kill glyphosate-resistant weeds, and some genetically modified crops are engineered to tolerate these mixtures.

Some things don’t change … check out our 2006 review regarding Canadian pesticide assessment and 2,4-D, published in the journal of the Canadian Paediatric Society.

Atrazine

Atrazine most famously causes male tadpoles to develop into reproductively functional females, when grown in the lab equivalent of agricultural ditch water. Thus, atrazine has complex effects on hormones and sensitive tissues (it is an “endocrine disrupting chemical”). For example, it can increase risks of cancer in oestrogen-sensitive tissues such as the breast and ovaries.

Atrazine is commonly used to kill weeds in corn fields, and is found in Canadian water. It was banned in Europe in 2003 due to widespread groundwater contamination. Eventually, encouraged by a lawsuit the PMRA started the legally-required review, but with planting season looming, on March 31, 2017 atrazine was re-registered. That same day a new special review was commenced, but it also resulted in no changes to atrazine registration. In September 2022, a label search finds 183 atrazine-containing products registered in Canada.

A brand new “Frankenstein” herbicide – Tiafenacil

Tiafenacil is a new herbicide, that inhibits a key enzyme to make chlorophyll.

Tiafenacil features several biologically-active, toxic groups, that are combined in a large molecule—a bit like a “Frankenstein” chemical.

This degrades into smaller molecules of toxic chemicals. For example, the top group with three fluorine atoms separates to form highly persistent trifluoroacetic acid. The PMRA found that young children would exceed the maximum allowable daily intake, then stated that is deemed to be acceptable because the assessment is “conservative.” This is hard to understand, given that the extrapolation (a.k.a. “safety”) factor for sensitive populations was eliminated, and there is no human data on this brand new pesticide.

Tiafenacil, US National Institutes of Health

Other toxic features include:

  • halogen atoms (fluorine [F], chlorine [Cl]) that make the chemical and its breakdown products more persistent and likely to be toxic;
  • rings that likely could interact with hormone receptors. The assessment document does not mention hormones nor the endocrine system, despite high frequency of fetal resorptions seen during animal testing.

Without followup, this system is broken.

First-time pesticide registrations are granted with no data about humans (testing of pesticides on humans is highly unethical), and with little if any experience with pesticide use or ingestion in the “real world.” This means that all new registrations require must include a plan and funding for longitudinal data collection and research, to check whether the “reasonable certainty of no harm to human health or the environment” hypothesis is correct.

That is the scientific method, and that is the law in Canada, yet no such followup for chemicals (including pesticides) occurs in Canada.

To take action to reduce pesticides in Canada, and to ban glyphosate, sign the Parliamentary Petition.