This reminds me of all the news reports of tests showing arsenic presence in rice (often due to rice being grown on soil where arsenic had been used as a pesticide for non-food crops such as cotton in the past).
But what (if any) health effects did the detected amounts of arsenic in rice have? How how much arsenic in rice would be safe? The FDA investigated these questions and finally came out with a report: [1][2]
Among their findings:
"In the general population, limiting levels of inorganic arsenic to 200 ppb or higher would not change the cancer risk significantly. Setting a limit below 200 ppb of inorganic arsenic in rice and rice products would decrease the risk. Setting a limit of 150 ppb of inorganic arsenic in rice and rice products would decrease the risk between 0% and 23%. The risk reduction is between 2% and 47% at a limit of 100 ppb of inorganic arsenic in rice and rice products. Finally setting a limit at 75 ppb of inorganic arsenic in rice and rice products would decrease the risk between 17% and 79%. The percentage of risk reduction is dependent on the product (see Table 5.6)."
"Setting a maximum level for inorganic arsenic in rice and rice products could affect availability in the U.S. market. For example, were we to set a maximum level of 100 ppb in these foods, the availability in the marketplace might decrease by 4% to 93%, depending on the type of rice."
"In the general population, the cancer risk would decrease in proportion to decreases in serving size and frequency of consumption of rice and rice products. Conversely, the risk would double over a lifetime if the consumption frequency were increased from 1 serving per day to 2 servings per day during that entire period (see Table 5.9)."
"Eliminating rice and rice products from the diets of infants and of children up to 6 years old could reduce the lifetime cancer risk from inorganic arsenic in rice and rice products by 6% and 23%, respectively. In other words, the risk model predicts that an infant not fed any rice or rice products has an approximately 6% lower chance of developing lung or bladder cancer from arsenic contamination of these foods, over the lifetime, compared with an infant who is fed these products (see Table 5.7)."
Based on their research, the FDA proposed a limit of 100 parts per billion for inorganic arsenic in infant rice cereal.[3] Unfortunately, they did not propose any limits on arsenic in rice or rice products apart from infant rice cereal, so how much rice is safe to eat is still an open question.
Still, their research and report are quite helpful in understanding the risk of arsenic exposure in rice, so consumers can now make informed decisions in regards to their own rice consumption. I hope the FDA will do something like that for glyphosate in food.
Also, such research and limits are prime examples of good work done by a government agency to keep us all healthy in the face of a food industry and "free market" which are clearly not able or willing to effectively regulate themselves.
[1] - https://www.fda.gov/Food/FoodborneIllnessContaminants/Metals...
[2] - https://www.fda.gov/Food/FoodScienceResearch/RiskSafetyAsses...
[3] - https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/u...