Since GMO crops came into cultivation two decades ago, human exposure to glyphosate has increased by approximately 500 percent, according to UC-San Diego scientists. But they say more research is needed on the impact of the chemical on human health. The research follows the listing of glyphosate, the most widely used herbicide in the world, by California regulators as a carcinogen.
In a paper published in the journal JAMA, the UCSD team said few people had detectable levels of glyphosate in their urine before GMO crops were adopted. By 2016, 70 percent of the people that they studied had detectable levels of it. The amount of glyphosate among people with detectable levels in their urine more than doubled over the 23 years covered by the study, which was based on urine samples from 100 participants from southern California who were part of a healthy-aging study.
In a UCSD release, professor Paul Mills said there are few studies on the effect of glyphosate on people but animal studies suggest long-term exposure can have adverse effects. Other studies indicate that long-term exposure to tiny doses can result in liver disorders. Said Mills, “The public needs to be better informed of the potential risks of the numerous herbicides sprayed onto our food supply so that we can make educated decisions on when we need to reduce or eliminate exposure to potentially harmful compounds.”
Use of glyphosate has skyrocketed since the 1990s because the first widely adopted GMO strains of soybeans and corn were developed to tolerate the weedkiller. Almost all of the corn, soybeans, cotton and sugar beets grown in the United States come from GMO seeds. The UCSD researchers said glyphosate also is sprayed as a desiccant on small grains, such as wheat and oats so they dry faster for harvest.