Poultry Drug Increases Levels of Toxic Arsenic in Chicken

BALTIMOREChickens likely raised with arsenic-based drugs, such as roxarsone, result in chicken meat that has higher levels of inorganic arsenic, according to a new study published online in the journal Environmental Health Perspectives. The study also found when roxarsone was present in raw meat, cooking decreased the levels of roxarsone and increased the levels of inorganic arsenic.

Arsenic-based drugs have been used in poultry production for decades to make poultry grow faster and improve the pigmentation of the meat. The drugs are also approved to treat and prevent parasites in poultry. In 2010, industry representatives estimated that 88% of the roughly nine billion chickens raised for human consumption in the U.S. received roxarsone. In July 2011, Pfizer voluntarily removed roxarsone from the U.S. market, but the company may sell the drug overseas and could resume marketing it in the United States at any time. Pfizer still domestically markets the arsenical drug nitarsone, which is chemically similar to roxarsone. Currently, there is no U.S. law prohibiting the sale or use of arsenic-based drugs in poultry feed. In January, Maryland became the first U.S. state to ban the use of most arsenicals in chicken feed.

Led by researchers at the Johns Hopkins Center for a Livable Future at the Bloomberg School of Public Health, this is the first study to show concentrations of specific forms of arsenic (e.g., inorganic arsenic versus other forms) in retail chicken meat, and the first to compare those concentrations according to whether or not the poultry was raised with arsenical drugs. The findings provide evidence that arsenical use in chickens poses public health risks and indicate the U.S. Food and Drug Administration (FDA) should ban arsenicals.

For the study, conventional, antibiotic-free, and USDA Organic chicken samples were purchased from 10 U.S. metropolitan areas between December 2010 and June 2011, when an arsenic-based drug then manufactured by Pfizer and known as roxarsone was readily available to poultry companies that wished to add it to their feed. In addition to inorganic arsenic, the researchers were able to identify residual roxarsone in the meat they studied; in the meat where roxarsone was detected, levels of inorganic arsenic were four times higher than the levels in USDA Organic chicken (in which roxarsone and other arsenicals are prohibited from use).

FDA has not established safety standards for inorganic arsenic in foods, although the agency did, for a brief time in 2011, suggest that concentrations should be well below 1 microgram per kilogram of meat. The levels of inorganic arsenic discovered in the meat where roxarsone was found were two and three times greater than that level.