It’s the chemical Monsanto depends on. How dangerous is it?
It’s hard to talk soberly about glyphosate, the active ingredient in Roundup. Roundup, as anyone following the GMO brouhaha knows, is the herbicide that genetically modified crops have been designed to tolerate. Glyphosate tolerance is a trait that allows farmers to spray the GM crops and kill the weeds but not the corn or soy. And so it’s inevitable that glyphosate is all wound up in GMOs, and the debate is commensurately heated.
The controversy amped up earlier this year when the International Agency for Research on Cancer, a World Health Organization agency, declared glyphosate a probable human carcinogen. Predictably, opponents of GMOs made hay over the report, urging consumer caution and regulatory attention. Equally predictably, GMO supporters questioned both the agenda of the agency and the quality of the assessment. Monsanto has commissioned a panel to review it.
It’s important to note that the IARC didn’t do new research (that’s not its job) but evaluated existing research. Other organizations, evaluating the same research, have reached different conclusions. Although the Environmental Protection Agency’s assessment of glyphosate, done in 1991, is woefully out of date (a new assessment is due this year), the agency last year took a fresh look specifically at cancer, in which it “reviewed over 55 epidemiological studies conducted on the possible cancer and non-cancer effects of glyphosate” and concluded that “this body of research does not provide evidence to show that glyphosate causes cancer. . . . This is the same conclusion reached in 2004 by the United Nations’ Food and Agriculture Organization and affirmed this year by Germany’s pesticide regulatory officials.”
I asked toxicologist David Eastmond, professor and chairman of the department of cell biology and neuroscience at the University of California at Riverside, to sort this out. There have been hundreds of studies on glyphosate, he said, and “with that number of studies, you’re always going to find some which give you positive results, tests that would suggest it could be toxic under certain conditions, and you can run with that.”