Increased levels of arsenic found in chicken
Researchers at Johns Hopkins University report finding arsenic in chicken that exceeds amounts that occur naturally and warned of a possible increase in cancer rates as a result.
Although the amount of arsenic in chicken was below danger levels established by federal safety standards in the 1940s, the researchers pointed out that such standards were established well over a half century ago. They also pointed out that chicken samples tested were from 2010 and 2011, which is before sales of the drug roxarsone were suspended.
Roxarsone was a major driver of the elevated arsenic levels, so even though a spokeswoman for the chicken industry said that the elevated arsenic amounts found by the researchers were still low, the researchers insist that the elevated levels are important because roxarsone has not yet been banned by the Food and Drug Administration and is still being sold abroad.
Much attention was drawn to the issue of arsenic in food last year when research by Consumer Reports found substantial arsenic amounts in rice. Arsenic residue in rice usually comes from water used in farming.
The lead author of the chicken study, Keeve Nachman, a scientist at the Johns Hopkins Center for a Livable Future, acknowledged that the amounts of inorganic arsenic in chicken were much lower than those found in rice. However, he also said that any deliberate additive amounted to a public health risk, adding that roxarsone (brand name 3-Nitro) and a chemically similar drug, nitarsone, remain the last federally approved uses of arsenic in food production.
Roxarsone is used to kill intestinal parasites while promoting growth and making meat more pink. The drug contains organic arsenic, a much less toxic version than its carcinogenic cousin: inorganic arsenic. The school of thought for decades has been that animals excreted the less toxic organic arsenic, but evidence from the new chicken study suggests it may also be converted into cancer-causing inorganic arsenic in the chicken.
For the chicken study, researchers tested meat samples that were collected from December 2010 to June 2011. They measured the samples for inorganic arsenic levels, and found roxarsone in about half of them. The reason the researchers said they tested samples from December 2010 to June 2011 was because those dates were before the sale of roxarsone was suspended, and they wanted to see if the drug is what led to the elevated levels of inorganic arsenic.
Meanwhile, a spokeswoman for the drug company that sells Zoetis said sales in the U.S. “remain suspended pending the ongoing evaluation of relevant scientific data regarding the use of this product in poultry.” The spokeswoman also said that the company no longer manufactures the drug, and that they are selling off the only remaining stock in markets that still permit it, which she says are all in Latin America.
According to a spokesman for the F.D.A., the company “has assured FDA that it will not begin marketing the drug again in the United States without first consulting with the agency.”
The chicken study, published May 11, 2013 in the journal Environmental Health Perspectives, tested 140 samples of chicken from grocery stores in 10 cities across the U.S., and found that chicken contained inorganic arsenic in amounts of about two parts per billion. Organic chicken was also tested, and contained about half a part per billion. Any amount below 500 parts per billion of total arsenic is allowed by federal standards.
If arsenic were fed to all chickens, the study estimated that exposure to the arsenic could result in an additional 124 deaths in America each year from lung and bladder cancer.
Sales of the drug roxarsone were suspended in 2011 after the FDA released a report finding inorganic arsenic in chicken livers. However, the FDA did not ban roxarsone, but simply reported that “any new animal drug that contributes to the overall inorganic arsenic burden is of potential concern.” Consumer advocates say the drug should be banned.
Part of the concern is that chicken consumption in this country has increased nearly tripled since the 1960s, with each American eating an estimated 83 pounds of chicken in 2011, compared to 30 pounds per person in 1965, according to the National Chicken Council; thus, more Americans are being exposed to the possible threat of arsenic.
In the meantime, the FDA spokesman says the agency “continues to investigate all uses of arsenic-based drugs in food-producing animals and will take the appropriate action to protect public health.”
SOURCE: Environmental Health Perspectives, published May 11, 2013 (doi:10.1289/ehp.1206245)