Use of arsenic-based drugs in poultry production increased the level of inorganic arsenic in chicken meat, posing a potential increase in the lifetime risk of bladder and lung cancer in consumers, according to a study conducted by researchers at the Johns Hopkins Center for a Livable Future.
The researchers tested conventional, conventional antibiotic-free, and organic chicken samples obtained from grocery stores in 10 U.S. metropolitan areas between December 2010 and June 2011. Seventy-eight cooked samples underwent arsenic speciation, and higher inorganic arsenic concentrations were detected in the conventional samples as compared to other types. Residues of roxarsone, an arsenic-based animal drug that was being used during that time in poultry production, were detected in 18 of the 40 conventional samples, one of 13 antibiotic-free samples, and none of the 25 organic samples.
Cooking increased the inorganic arsenic levels and decreased roxarsone concentrations, the researchers reported. According to researchers, although the concentrations of inorganic arsenic in the conventional samples—about two parts per billion—were lower than the 500 parts per billion federal standard, lifetime exposure to even those low levels could result in 3.7 extra lifetime bladder and lung cancer cases per 100,000 exposed people.
Keeve E. Nachman, PhD, MHS, first author of the study, which was published in Environmental Health Perspectives, argues that federal standards regarding inorganic arsenic levels are outdated. “They have not been revised in many decades and are obsolete. They ignore volumes of epidemiologic research linking inorganic arsenic exposure to cancers and other effects published long after the setting of those standards,” he says in an email to Food Quality.
U.S. sales of roxarsone were suspended by its manufacturer in 2011 in response to a study by the FDA, but the drug’s approval has not been withdrawn. Nitarsone, another arsenic-based drug, is now used for conventional poultry production in the U.S.
“We feel that our study provides the basis for the FDA to withdraw the approvals for arsenic-based drugs. Our study strongly suggests that using these drugs increases the inorganic arsenic levels in chicken meat. The FDA has stated that any drug that does this is of concern,” Dr. Nachman says.
Ashley Peterson, PhD, vice-president of scientific and regulatory affairs at the National Chicken Council, disagrees. In a statement from the trade association, she notes that the chicken samples in the study were collected before U.S. sales of roxarsone were suspended. Describing the research as “misleading” and “agenda-driven,” Dr. Peterson says that the level of inorganic arsenic found in the chicken meat was “extremely low” and that consumers are regularly exposed to arsenic, a naturally occurring element in the earth’s soil, air, and water.