This is a really good article with a lot of links to "Additional Sources and Studies about Glyphosate: For those who want as many scientific references, peer-reviewed studies, and reports as possible…"
Presented below are ten sobering facts about Glyphosate (the key ingredient in Monsanto’s RoundUp weedkiller, which the majority of Monsanto’s seeds are genetically engineered to withstand):
4) Glyphosate is not breaking down as promised
In 1996, New York’s attorney general sued Monsanto over the company’s use of “false and misleading advertising” about RoundUp. That case ended with Monsanto agreeing to stop calling Roundup “biodegradable,” and to pull ads claiming that Roundup was “safer than table salt,” “practically nontoxic,” and “stayed where you put it.”
Two decades after the advent of “RoundUp Ready” crops and their dominance in the agricultural marketplace, the evidence of their falsehoods abound: multiple studies have found significant levels of glyphosate in streams, soil, air, rainwater, and groundwater:
In our food: a recent study found that Glyphosate residues in the main foods of the Western diet – sugar, wheat, and genetically modified corn and soy – inhibit critical enzymes in mammals [which] manifests slowly over time, as inflammation damages cellular systems throughout the body. Source: http://www.mdpi.com/1099-4300/15/4/1416