 When arsenic-containing drugs are fed to chickens, not only does it grow out into their feathers, which can then be fed back to them as a slaughterhouse byproduct, the arsenic can get into their tissues and then into our tissues, explaining why national studies found that those who eat more poultry have tended to have more arsenic flowing through their bodies. Why would the industry do that? In modern poultry CAFOs, these concentrated animal feeding operations, there can be 200,000 birds under one roof, and so the floors of these buildings become covered with feces. While this so-called factory farming decreases costs, this also increases the risk of disease. That's where arsenic-containing drugs and other antibiotic feed additives can come in to try to cut down the spread of disease in such an unnatural environment, to which you can imagine a smug vegetarian's gloating how glad they are they don't eat chicken, but what do you think happens to the poop? The arsenic from the drugs in the feed can get into our crops, into the air, and into the groundwater, and find its way into our bodies, whether we eat meat or not. Yeah, but how much arsenic are we really talking about? Well, we raise billions of chickens every year, and if historically the vast majority were fed arsenic, then if you do the math, we're talking about dumping a half million pounds worth of pure arsenic into the environment every year, much of it onto our crops, or shovel directly into the mouths of other farm animals. Most of the arsenic in chicken waste is water-soluble, so there are certainly concerns about it seeping into the groundwater, but if it's used as a fertilizer, what about our food? Studies on the levels of arsenic in the U.S. food supply dating back to the 70s identified two foods, fish aside, with the highest levels, chicken and rice, both of which can accumulate arsenic in the same way. They're an arsenic-containing drug like rocks are sown to chickens, and it ends up in their manure, which ends up in the soil, which ends up in our pilaf. Rice is now the primary source of arsenic exposure in a non-seafood diet. I was surprised to see mushrooms in the top five food sources of arsenic, but then not so surprised when I found out that poultry litter was commonly used as a starting material to grow mushrooms in the United States. And over the years, mushroom arsenic content has rivaled the arsenic concentration in rice, though people tend to eat more rice than mushrooms on a daily basis. And arsenic levels in mushrooms did seem to be dipping, starting about a decade ago, confirmed in this latest 2016 paper that looked at a dozen different types of mushrooms, human white-button mushrooms, cremini, portobello, shiitake, trumpet, oyster, nemiko, never heard of it, mayotake, alba clamshell, brown clamshell, never heard of those either, and shantarelle. Now only averaging about half what rice is running. Just like some mushrooms have less arsenic than others, some rice has less. Rice grown in California has 40% less arsenic than rice grown in Arkansas, Louisiana, Mississippi, Missouri, and Texas. Why? Well, arsenic-based pesticides have been used more than a century on millions of acres of cotton fields. Noted to be a dangerous practice, back in 1927, arsenic pesticides are now effectively banned, so it's not a matter of buying organic versus conventional rice, because millions of pounds of arsenic had already been laid down in the soil well before your rice was even planted. The rice industry is well aware of this. There's an arsenic toxicity disorder in rice, called straighthead, where if you plant rice in soil too heavily contaminated with arsenic, it doesn't grow right. So instead of choosing cleaner cropland, they just developed arsenic-resistant strains. So now lots of arsenic can build up in rice without the plant getting hurt. Can the same be said, however, for the rice consumer? Same story with wine, decade after decade of arsenic pesticide use, and even though they've been banned now, arsenic can still be sucked up from the soil, leading to the pervasive presence of arsenic in American wine, which could pose a potential health risk. Curiously, they sum up by saying chronic arsenic exposure is known to lower IQ in children, but if kids are drinking that much wine, arsenic toxicity is probably the least of their worries.