Residue of doubt

Glyphosate is arguably the most popular herbicide in the world. Since the 1970s, Monsanto has been marketing it to farmers under the trade name Roundup. While glyphosate was initially welcomed by farmers because it saved them the cost of employing labourers to pluck out weeds, its popularity grew exponentially after Monsanto developed genetically engineered seeds that were resistant to the herbicide. That is, farmers could blanket-spray their fields with Roundup and be rest assured that it wouldn’t harm their cotton or corn. On the other hand, several environmentalists argue that exposure to glyphosate is harmful to humans. There have been tests carried out on mice and rabbits to determine the doses at which glyphosate can be dangerous. There have been studies to show that key biochemical pathways in human cells are disrupted when exposed to glyphosate. There have also been studies to determine if glyphosate can find its way into the skin of farmers and gardeners who use them, and affect their health. So far, there’s been no conclusive evidence that it does.

Earlier this month, however, a study, ‘Glyphosate exposure in pregnancy and shortened gestational length: a prospective Indiana birth cohort study’, in the peer-reviewed Environmental Health, proffered evidence for glyphosate in the urine samples of 71 pregnant women in Central Indiana. Of the women, 93% had glyphosate “above the limit of detection” in their urine. An earlier study in Germany had reported finding glyphosate in the urine of some people who consumed non-organic meat. However in all these studies, the glyphosate levels were extremely low and below toxicity levels. The women in the study didn’t contract it through drinking water (pesticides used in agriculture can sometimes make their way into drinking water). So, the only way the glyphosate had made its way was through their diet. Indiana is known for heavy cultivation and consumption of genetically modified corn.

The researchers also report another intriguing observation: “We observed no correlations with foetal growth indicators such as birth weight percentile and head circumference. However, higher glyphosate urine levels were significantly correlated with shortened gestational lengths.”

What makes the study significant is the fact that this is a rare instance of a common crop chemical being detected in people. The Indiana study shouldn’t set alarm bells ringing in India yet, but it certainly merits an equivalent follow-up here.