The chicken industry's largest trade group has previously claimed that arsenic levels in its birds are safe. "We are not aware of any study that shows implications of any possibility of harm to human health as the result of the use of these products at the levels directed," said Richard Lobb, a spokesman for the National Chicken Council.
Soils are contaminated with arsenical pesticides from chicken manure; chicken litter containing arsenic is fed to other animals.
Arsenic levels in young chickens, or "broilers," may be three to four times greater than in other poultry and meat.
According to a 2007 issue of Chemical & Engineering News, chicken feed may pose health risks to humans who eat meat from chickens that are raised on the feed.
Although arsenic is a naturally occurring element found in food, drinking water and the environment, exposure to high levels of the inorganic form, such as that found in preservatives, insecticides and weed killers, can be deadly.
Factory farmed chickens are also exposed to infections from improper handling, air and soil pollution, environmental toxins, preservatives, metals and many other chemicals infused in all the vaccinations they receive.
In 2011 the U.S. Food and Drug Administration (FDA) found that the livers of roxarsone-treated chickens had elevated levels of iAs, a known human carcinogen. In response, roxarsone’s manufacturer, Pfizer, voluntarily pulled the drug off the U.S. market, although it is still sold overseas, and a similar arsenical drug is still available in the United States. Sampling for the new study took place between December 2010 and June 2011, before Pfizer withdrew roxarsone from the U.S. market.
Roxarsone is an organic form of arsenic, which although less toxic to humans than the inorganic species implicated in cancer, has been shown to affect the growth of endothelial cells in culture. When roxarsone was approved by the FDA it was believed the drug passed through chickens unchanged. The FDA and new EHP studies each suggest that roxarsone can transform into iAs and accumulate in the edible portions of the birds, making the toxic metal available for human consumption.
For the current study, lead author Keeve Nachman, director of the Farming for the Future program at the Johns Hopkins Center for a Livable Future, and colleagues analyzed chicken breast meat samples from three categories: 1) conventional chickens for which arsenical drug use was permitted (69 samples); 2) conventional antibiotic-free chickens for which arsenical drug use was unlikely but possible since arsenical drugs are not considered antibiotics (34 samples); and 3) chickens certified as organic by the U.S. Department of Agriculture, which are not fed roxarsone and other arsenical feed additives (37 samples). The samples came from 82 stores in 10 U.S. metropolitan areas. Some of the samples underwent arsenic speciation, and for a subset of these the authors compared paired cooked and raw samples.
Another Reason to Buy Organic Meat
The results showed that iAs was highest in cooked conventional chicken meat (with a geometric mean of 1.8 Âµg/kg) and lowest in cooked organic chicken meat (with a geometric mean of 0.6 Âµg/kg). According to Nachman, arsenic found in organic chicken meat reflects exposure from other potential sources, such as drinking water. In addition, chicken meat with detectable roxarsone had higher iAs concentrations than chicken meat without detectable roxarsone.
The study authors also performed a risk analysis based on iAs concentrations measured in their samples, estimates of the amount of chicken consumed over a 70-year lifetime, and the relationship between iAs consumption and the risk of cancer. Based on these assessments, they estimated that if all chicken producers were to use arsenic-based drugs, the added iAs exposure from consuming chicken would result in an additional 3.7 bladder and/or lung cancers per 100,000 people, or an average of 124 cancers in the United States per year. "Our study gives the FDA a clear rationale for withdrawing its approval for roxarsone and potentially other arsenic-based drugs in animal agriculture," Nachman says.
The authors’ risk assessment assumed a cancer slope factor for iAs that’s more than 17 times higher than the cancer slope factor adopted by the EPA in 1998 for skin cancer. According to Yu Chen, an associate professor at the New York University School of Medicine, the higher value reflects epidemiological evidence from studies conducted in Taiwan suggesting heightened risks for bladder and lung cancer from iAs exposure. But the higher cancer slope factor--which was proposed by the EPA in 2010 and has since been withdrawn pending further agency review--has been heavily disparaged by industry stakeholders, who criticize the methods and data used by the EPA in its doseâ€“response assessment. A National Research Council panel is currently evaluating the EPA’s toxicological assessment of iAs.
Measurable levels of IAs end up in all chicken products sold to grocery retailers which is then consumed and ingested by the population.
Researchers estimate that between 11 and 12 metric tons of arsenic are applied to agricultural land there every year via poultry waste. Groundwater tests on both sides of the Chesapeake Bay's Coastal Plains found arsenic in some household wells reaching up to 13 times the Environmental Protection Agency's (EPA) tolerance limit.
Then there's the question of arsenic traces in industrial chicken meat. In 2006, the Institute for Agriculture and Trade Policy (IATP) tested chicken samples from supermarkets and fast-food joints -- and found that 55 percent contained detectable arsenic. Citing the EPA, IATP reckons that 55 percent of arsenic found in poultry meat is inorganic, i.e., toxic. And here's another way arsenic from poultry feed gets into the food supply: the jaw-dropping, mind-boggling practice of feeding chicken feces to cows.
So how did the practice of dosing poultry with arsenic come to pass -- and what are the regulatory agencies doing about it? Food and Water Watch's Patty Lovera explains that the practice got the green light during the FDR administration, when the science on arsenic was much less advanced. According to Lovera, the government hasn't revised its standards for arsenic levels in poultry, "even as chicken consumption has increased dramatically." As for testing, well, it's so lax as to be functionally nonexistent:
This study highlights the importance of controlling point sources of arsenic and other chemicals and suggests that management practices--such as properly storing dry litter and controlling litter spills outside storage facilities--can help protect local regions from the migration of arsenic and other agricultural pollutants.
In the meantime, Amy Sapkota, an assistant professor at the University of Maryland School of Public Health who was not involved in the study, argues that the study is strong. She says, "It provides FDA with good data about whether it should formally withdraw the use of arsenicals from chicken production in the U.S."
Marco Torres is a research specialist, writer and consumer advocate for healthy lifestyles. He holds degrees in Public Health and Environmental Science and is a professional speaker on topics such as disease prevention, environmental toxins and health policy.