Sampling 100 humans in a southern California town, researchers compared urine samples from 1993-1996 to samples from 2014-2016 and found that the number of people who had detectable levels of glyphosate in their urine grew from "very few" to 70% of the individuals sampled.
In addition, the amount of glyphosate in each individual increased on average more than 500%.
The press release issued by UCSD stated,
"There are few human studies on the effects of glyphosate, but animal studies demonstrate that chronic exposure to glyphosate-based herbicides can have adverse effects, said Mills. The authors point to other studies in which consistently feeding animals an ultra-low dosage of glyphosate resulted in liver disorders similar to nonalcoholic fatty liver disease in humans."The researchers point to the dramatic rise in the use of glyphosate in the food supply with the increased use of GMO crops. Glyphosate is also commonly sprayed as a desiccant to dry out crops before harvest. Wheat (and therefore bread) and potatoes are the most common way most people ingest glyphosate.
Though the wine industry's use of glyphosate is not as dramatic of a story, studies like these are increasing awareness among consumers of the prevalence and dangers of glyphosate, giving rise to new consumer health trend that the wine industry has not yet anticipated how to come to terms with.
For a good summary of the animal studies on glyphosate, see NRDC scientist Christopher Portier's excellent presentation to EU officials which you can read here.
The EPA first declared glyphosate to be carcinogenic back in 1984, but later reversed its position after political pressure.