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The Pesticide Effect: Glyphosate

How does glyphosate effect our health?
Glyphosate is a broad-spectrum herbicide used to kill weeds which works by inhibiting an enzyme found in plants. There are around 200 products containing glyphosate registered for use in Australia. Glyphosate has been registered for use for over 40 years.

It’s probably in our garage and on our lawn.

And it’s used on nearly every orchards, vineyards, and plantation crops. But what risks does it pose?
An international agency declared glyphosate, the primary ingredient in the popular product Roundup, a “probable human carcinogen.” The weed killer also has made recent headlines for its widespread use on genetically modified seeds and research that links it to antibiotics resistance and hormone disruption. Several governments are planning to restrict its use.

So what do we know about glyphosate? How Is Glyphosate Used?
Introduced commercially by Monsanto in 1974, glyphosate kills weeds by blocking proteins essential to plant growth. It is now used in more than 160 countries.

Glyphosate, often sold under the brand name Roundup, is probably in our garage or shed because it’s the second most widely used lawn and garden weed killer.

These products have been promoted as easy-to-use and effective on poison ivy, kudzu, dandelions, and other weeds.

Its use skyrocketed after seeds were genetically engineered to tolerate the chemical, because these seeds produce plants that are not killed by glyphosate.

Farmers can apply the weed killer to entire fields without worrying about destroying crops.

There is no information on how much people are exposed to from using it in their yards, living near farms or eating foods from treated fields.

Glyphosate also was found in about 70 percent of rainfall samples. It “attaches pretty firmly to soil particles” that are swept off farm fields then stay in “the atmosphere for a relatively long time until they dissolve off into water,” says Capel, an adjunct associate professor in the University’s Department of Civil Engineering.

What about Exposure Through Food?
Before genetically engineered crops, glyphosate residues in food were considered unlikely, says Charles Benbrook, research professor at Washington State University’s Centre for Sustaining Agriculture and Natural Resources. But since about 2005, pre-harvest use of glyphosate “results in very high residues,” he says. Traces were found in 90 percent of 300 soybean samples.

What is known About Effects on Human Health?
The U.S. Environmental Protection Agency had determined that the science “does not provide evidence to show that glyphosate causes cancer.”

But now the EPA says it will analyse new findings by the UN’s International Agency for Research on Cancer or IARC, which declared in March that glyphosate probably raises the risk of cancer in people exposed.

The UN agency based its decision on human, animal, and cell studies, says National Cancer Institute scientist emeritus, Aaron Blair who chaired the IARC review committee.

The studies found glyphosate in farm workers’ blood and urine, chromosomal damage in cells, increase risks of digestive problems, increased risks of neurological diseases in people exposed, and tumour formation in some animal studies. (1) (2)

The big unanswered question is the potential health effect of low levels over extended periods of time.

Monsanto called the IARC conclusion “inconsistent with decades of ongoing comprehensive safety assessments.” One study suggests that glyphosate may affect pathogens such as Salmonella in ways that can contribute to antibiotic resistance. Other recent research suggests it can interfere with hormones.

Where Does This Leave Us?
The EPA is reviewing its approved uses of glyphosate and expects to release a preliminary assessment of the human health risk later this year. This is expected to include new restrictions.

Meanwhile, Sri Lanka, alarmed by suspected links to kidney diseases has banned it.(3)

Brazil is considering a similar move. Mexico and the Netherlands have imposed new restrictions, and Canada has just begun a process to consider new rules.


  1. Samsel A, Seneff S. Glyphosate, pathways to modern diseases III: Manganese, neurological diseases, and associated pathologies. Surg Neurol Int. 2015 Mar 24;6:45. doi: 10.4103/2152-7806.153876. eCollection 2015. PubMed PMID: 25883837; PubMed Central PMCID: PMC4392553.
  2. Samsel A, Seneff S. Glyphosate, pathways to modern diseases II: Celiac sprue and gluten intolerance. Interdiscip Toxicol. 2013 Dec;6(4):159-84. doi: 10.2478/intox-2013-0026. Review. PubMed PMID: 24678255; PubMed Central PMCID: PMC3945755.
  3. Jayasumana C, Gunatilake S, Siribaddana S. Simultaneous exposure to multiple heavy metals and glyphosate may contribute to Sri Lankan agricultural nephropathy. BMC Nephrol. 2015 Jul 11;16:103. doi: 10.1186/s12882-015-0109-2. PubMed PMID: 26162605; PubMed Central PMCID: PMC4499177.

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