A study published in Environmental Health Perspectives by the Johns Hopkins Center for a Livable Future (CLF) last week found that feeding arsenicals to chicken increases the concentrations of inorganic arsenic, a known carcinogen, in chicken breast meat. This is the first study that shows concentrations of specific forms of arsenic in retail chicken meat and the first to compare those concentrations according to whether the poultry was raised with arsenical drugs.
Researchers bought conventional, antibiotic-free, and USDA organic chicken samples from 10 U.S. cities between December 2010 and June 2011, when an arsenic-based drug manufactured by Pfizer, called roxarsone, was available to poultry companies. Scientists not only found inorganic arsenic in the meat; they also found residual roxarsone. In fact, when roxarsone was found, levels of inorganic arsenic were four times higher than levels in USDA organic chicken, in which arsenicals are prohibited.
The study says that “compared to organic chicken consumers, we estimated that conventional chicken consumers would ingest an additional 0.11µg/day iAs. Assuming lifetime exposure and a proposed cancer slope factor of 25.7 (mg kgBW-1 day-1)-1, this could result in 3.7 extra lifetime bladder and lung cancer cases per 100,000 exposed-persons.”
Arsenic-based drugs have been used in poultry production for decades to make poultry grow faster and to improve meat pigmentation, as well as treating and preventing parasites. In 2010, 88% of the chickens raised for human consumption in this country received roxarsone. In 2011, Pfizer removed the chemical from the U.S. market, but they still sell it overseas. And the company markets the arsenical drug nitarsone which is chemically similar to roxarsone.
Chronic inorganic arsenic exposure causes lung, bladder, and skin cancers and has been associated with heart disease, type 2 diabetes, cognitive defects, and adverse pregnancy outcomes. Since at least 75% of Americans regularly eat chicken, the scope of this problem is vast. The FDA has not established safety standards for inorganic arsenic in foods, although in 2011 the agency did suggest that concentrations should be well below 1 microgram per kilogram of meat. The levels of inorganic arsenic found in this study were two and three times greater than that level.
Cooking decreases the levels of roxarsone and increases the levels of inorganic arsenic. But a study published by the Johns Hopkins School of Public Health found that roxarsone is converted into a more carcinogenic form during cooking. The chemical could come back onto the market at any time, since it is still approved for use by the FDA.
