Funky chicken.

Consumers Exposed to Arsenic in Poultry Between 1966 and 2000, average annual chicken consumption in the United States jumped from 32.1 to 81.2 pounds per person. Earlier studies have shown that trace elements ingested by chickens such as iron, iodine, and zinc can end up in the chicken meat that humans eat. This month, Tamar Lasky, an epidemiologist now with the NIH, and her colleagues at the Food Safety and Inspection Service (FSIS) of the U.S. Department of Agriculture report that American chicken consumers may be taking in more arsenic than previously suspected [EHP 112:18 21].

Arsenic occurs naturally in the Earth's crust, and people are exposed to it in drinking water, dust, and foods. Inorganic arsenic is more toxic than organic forms, and is classified as a carcinogen; studies have linked chronic exposures of 10-40 micrograms per kilogram per day ([micro]g/kg/day) with skin, respiratory, and bladder cancers. Among foods, seafood, rice, mushrooms, and poultry contain some of the highest reported arsenic levels. Arsenic is an approved feed supplement that farmers use to control intestinal parasites in chickens--especially young chickens ("broilers"), which are more vulnerable to such parasites--provided they wait five days after dosing to slaughter, to allow time for the toxicant to pass through the birds' bodies. Current data suggest that 65% of the arsenic in poultry is inorganic.

Since 1970, the FSIS has monitored meat and poultry through its National Residue Program, mainly in order to determine chemical residue levels in food and prevent contaminated goods from reaching the public. Lasky and colleagues analyzed the reported arsenic content of more than 20,000 meat samples taken by the FSIS between 1993 and 2000, including more than 5,000 chicken samples. They found that young chickens showed arsenic concentrations 3-4 times higher than those for mature chickens or other meat types: mean levels for young chickens were 0.33 0.43 parts per million. In 1997, broilers represented 99% of chickens consumed.

The researchers used data on chicken consumption from a Department of Agriculture survey to estimate the mean amounts of chicken consumed by the U.S. population at the 50th, 95th, and 99th percentiles. By multiplying the amount of chicken consumed by estimates of arsenic in chicken muscle (the most popular form of the meat consumed), the researchers estimated the amount of arsenic ingested by the general population and various subgroups.

Lasky and colleagues calculated that a person consuming an average of 60 grams (about 2 ounces) of chicken per day may be getting 3.52-5.24 [micro]g of inorganic arsenic daily. For a person weighing 70 kg (154 pounds), this breaks down to 0.05-0.07 [micro]g/kg/day, well below the joint Food and Agriculture Organization of the United Nations/World Health Organization tolerable daily intake of 2 [micro]g/kg/day inorganic arsenic. But groups that tend to eat more chicken (including children, people aged 55 and older, and African Americans) may face doses up to 10 times higher, constituting a sizable proportion of their tolerable daily intake.

The arsenic concentrations found in this study lead the authors to conclude that assumptions about the public's exposure to arsenic in food and water might need to be recalibrated by regulatory agencies. These initial reports on arsenic levels, they add, "may be useful in risk assessments of arsenic exposure and its consequences."