Glyphosate residue results a matter of perspective

“Oh my God, there’s gly-phosate in our food,” many consumers said after hearing the results of a residue study by the Canadian Food Inspection Agency.

Meanwhile, many people in agriculture looked at the same results and said, “wow, this is good news. Residue levels are almost all below the stringent tolerances.”

It’s all a matter of perspective. Different people and news agencies looking at the same report came away with different interpretations.

Nearly 3,200 samples of domestic and imported food were tested. Overall, 98.7 per cent were below Canada’s maximum residue limits for glyphosate, but this wasn’t the headline used in most new reports.

Instead, reports tended to emphasize the 1.3 per cent of sample that were above the MRL and particularly the 3.9 per cent of grain samples that were higher. Most reports did not explain that on some grains, no MRL has been established, so the limit reverts to a very low level that in a few cases was exceeded.

The science around setting MRLs is complicated, but huge safety factors are incorporated. Generally speaking, MRLs are set with a safety factor of at least 100. When the vast majority of tests are below a very conservatively set MRL, it really is a good news story.

Missing and misaligned MRLs are a big problem in world trade. What’s deemed safe in one country may not be acceptable in another just because they haven’t done the scientific analysis.

Some headlines made it sound like the discovery of any residue, no matter how minute, should be a source for concern. A CBC report posted online contained the headline, “Nearly a third of food samples in CFIA testing contain gly-phosate residues.” Other reports emphasized that glyphosate had been found in more than 30 percent of infant foods.

It’s not at all surprising that glyphosate residues were discovered. Glyphosate has long been used as a pre-harvest aid. Spraying late in the season typically means a small but acceptable level of residue in the harvested production.

By comparison, a Roundup Ready crop sprayed with glypho-sate for weed control early in the growing season would be much less likely to leave a measurable residue. For glyphosate used for weed control before crop emergence, you would expect no residue.

Glyphosate is the most widely used herbicide in the world and is the product most associated with Monsanto, one of the most vilified companies in the world. As a result, the herbicide receives a lot of attention from environmentalists and health advocates.

It’s important to keep studying the potential for long-term health issues, but it’s even more important to keep past reports in perspective. When some controversial scientific studies labelled glypho-sate “as probably carcinogenic to humans,” this was a hazard assessment rather than a risk assessment.

Whether glyphosate might potentially cause cancer at some ridiculously high level of continuous exposure is dramatically different than real world exposure levels.

Most of us drink coffee and consume caffeine at levels 100 times higher than the scientifically determined acceptable daily intake. Why then is such worry warranted over exposure to glyphosate that is 100 times lower than the acceptable daily intake?

Alas, it’s difficult to win scientific arguments with concerned consumers. They often don’t read beyond the headlines, and the headlines are designed to capture attention. Even when the overall news is positive, the information can be cast in a negative light.

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