
Recent news coming out of the Centers for Disease Control and Prevention (CDC) in the United States of America shows evidence of human urine samples containing detectable traces of glyphosate – a widely used weed killer in agriculture. This news is even more concerning because glyphosate is likely the most used weed killer around the world and multiple studies suggest that it probably causes non-Hodgkin lymphoma – a type of cancer – to humans. As of 2020, glyphosate was the most widely used weed killer in Canada. Its use in agriculture has dropped since but the possible effects in humans due to ingestion via food up until the reduction in use or bans may still prevail. The issue of pesticide residue contamination continues to be a hot topic. Contrary to the latest reports, some weed killer manufacturers insist that glyphosate is safe if residues are consumed via food below safe concentrations. Some food samples tested in Canada have been found to exceed maximum residue limits. However, these samples may still be safe for consumption.
Even though pesticides must be approved by Health Canada’s Pest Management Regulatory Agency (PMRA) before use in Canada, this does not guarantee proper application. For many different reasons such as spray drift and uneven cropland, under- or overapplication may still occur. The likelihood of application errors is however reduced by the restriction of crop protection product application to trained and licenced personnel. The low probability of this still reiterates the need to develop technologies that increase efficiency of use by spot spraying, thereby reducing the likelihood of the presence of pesticide residues on food. Some farmers have stopped using glyphosate altogether. They have resorted to using alternative weed killers, but this is likely because there is currently insufficient negative evidence of the effects of substitute weed killers.
My research is investigating ways in which spot spraying could be made possible for practical deployment in agriculture. The goal is to avoid spraying weed killers such as glyphosate everywhere in the field. For example, if a farmer plans to apply fungicides everywhere in the field and only kill a few weeds that are present, they could use a spot sprayer that I am developing. The technology being developed will be designed for easy integration on existing sprayers to ensure minimal operation interference. The modification will also enable cost savings associated with having to change the entire machine altogether as studies show that cost and convenience are likely the main adoption barriers for new technologies in agriculture.
Investigations of glyphosate as a weed killer are required to evaluate further risks. However, relying on further cancer-related evidence may not be the best approach towards banning or reducing use. Therefore, I believe the outcome of my research will influence decisions from various stakeholders independent of pesticide residue usage. I expect to see the much-needed changes in standards related to application of crop protection products with sufficient evidence obtained from my studies.
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