Glyphosate is the active ingredient in the pervasive herbicide, Roundup. Its usage on crops to control weeds in the United States and elsewhere has increased dramatically in the past two decades.
The increase is driven by the increase over the same time period in the use of genetically modified (GM) crops, the widespread emergence of glyphosate-resistant weeds among the GM crops (necessitating ever-higher doses to achieve the same herbicidal effect), as well as the increased adoption of glyphosate as a desiccating agent just before harvest.
GM crops include corn, soy, canola (rapeseed), and sugar beet. Crop desiccation by glyphosate includes application to non-GM crops such as dried peas, beans, and lentils.
It should be noted that the use of glyphosate for pre-harvest staging for perennial weed control is now a major crop management strategy.
The increase in glyphosate usage in the United States is extremely well correlated with the concurrent increase in the incidence and/or death rate of multiple diseases, including several cancers.
These include thyroid cancer, liver cancer, bladder cancer, pancreatic cancer, kidney cancer, and myeloid leukemia. The World Health Organization (WHO) revised its assessment of glyphosate's carcinogenic potential in March 2015, relabeling it as a "probable carcinogen."
Why Other Countries Have Banned Glyphosate
Sri Lanka's newly elected president, Maithripala Sirisena, banned glyphosate imports as one of his first acts following election.
This action was based on studies by Jayasumana et al. that provided compelling evidence that glyphosate was a key factor in the chronic kidney disease that was affecting an alarming number of young agricultural workers in the northern region, and was probably further motivated by the WHO reevaluation of its carcinogenic potential.
Kidney disease is a risk factor for multiple cancers, with kidney dialysis being associated with increased risk of Kaposi's sarcoma by more than
50-fold, with 3- to 10-fold increased risk of kidney cancer, and 2- to 9-fold increased risk of thyroid cancer.
Many other cancers also show more modest risk increases. A study of rats fed GM maize and/or Roundup in their water over their entire lifespan revealed significantly increased risk of massive mammary tumors in the females, along with kidney and liver damage in the males.
Most of the tumors were benign, but there were three metastases (in female animals) and two Wilm's tumors found in the kidneys of males, which had to be euthanized early due to the excessive tumors, which grew to more than 25 percent of their body size.
The exposed animals also had a shortened life span compared to the controls.