Some kids in Utah were found to have high levels of arsenic in their bodies and they traced the source to the eggs they were eating from their backyard chickens. Apparently the feed contained roxarsone, an arsenic based additive common in chicken feed. Grist has the scoop;
Used in combination withantibiotics, arsenic helps keep chickens, turkeys, and pigs from getting sick in crowded conditions, and also makes them grow bigger, faster. While this sounds nuts -- feeding a notorious poison to animals you plan to eat -- the poultry industry, along with Food and Drug Administration officials, is quick to point out that there are two kinds of arsenic: inorganic, aka the cancer-causing "bad" kind, which occurs naturally in the environment in combination with other elements such as oxygen, chlorine, and sulfur; and organic. No, not the kind you can get from Whole Foods: in this case "organic" refers to compounds containing carbon, or hydrogen. Organic arsenic is considered less toxic, and that's what's used in animal feed, usually in the form of roxarsone.
The key word there is "less." FDA spokesperson Ira Allen wrote in an email to me that:
FDA completed food safety assessments in conjunction with the approval of the arsenic-containing animal drug products. As part of that assessment process, FDA established tolerances for the presence of arsenic in animal-derived food. For example, the tolerance for total arsenic in uncooked muscle tissue from chickens is 0.5 parts per million (ppm). FDA does not at this time have evidence that residues of total arsenic in animal-derived food are exceeding the established tolerances.
Looks like our chickens are going to get an upgrade to spendy organic chicken feed.