Chicken Feed Effects Questioned
Researchers study health, environmental impact from use of arsenic
JOHN VANDIVER / Daily Times (Maryland) 4jan04
Under the conditions of these 2-year feed studies, there was equivocal evidence of carcinogenic activity of roxarsone for male F344/N rats, as indicated by a marginally increased incidence of adenomas of the exocrine pancreas.
Ristat; Ren-O-sal; 3-nitro; 3-nitro-10;
Mean Total Arsenic Concentrations in Chicken 1989–2000 and Estimated Exposures for Consumers of Chicken
Environmental Health Perspectives v.112, n.1 Jan04
Tamar Lasky, Wenyu Sun, Abdel Kadry, and Michael K. Hoffman Office of Public Health and Science, Food Safety and Inspection Service, U.S. Department of Agriculture, Washington, DC, USA
The purpose of
this study was to estimate mean concentrations
of total arsenic in chicken liver tissue and then estimate total
and inorganic arsenic ingested by humans through chicken
consumption. We used national monitoring data from the Food
Safety and Inspection Service National Residue Program to
estimate mean arsenic concentrations for 1994–2000.
source: http://ehp.niehs.nih.gov/members/2003/6407/6407.html 4jan04
SALISBURY -- Since the 1970s, the poultry industry has used certain arsenic-based ingredients as chicken feed additives, but some researchers have started to scrutinize the long-standing practice because of possible health and environmental risks.
A common arsenic used by chicken companies is roxarsone, which is mixed with feed to control intestinal parasites and promote growth, according to research chemists.
After consuming roxarsone, the arsenic additive approved for use by the Food and Drug Administration, chickens then excrete the compound in a chemical form that is virtually unchanged.
On the Delmarva Peninsula, poultry growers raise more than 500 million birds annually, producing vast amounts of chicken litter that is spread on farmland as manure.
Questions about potential risks associated with the use of roxarsone center on the practice of spreading manure, not the consumption of poultry. Very low levels of roxarsone are retained in chicken. The FDA limits the amount to 0.5 parts per million in muscle tissue.
Dr. Ellen Silbergeld, a researcher from the Johns Hopkins School of Public Health, said the poultry industry's practice of using arsenic compounds in its feed is something that has not been studied.
"It's an issue everybody is trying to pretend doesn't exist," she said.
Silbergeld, who is leading a study on the effects of antibiotic resistant illnesses among Lower Shore poultry workers, said she intends to initiate a research project examining what risks are associated with exposure to arsenic on industry workers.
"The arsenicals are there. Are they significant amounts? That's the issue," she said.
In Maryland, 338,679 tons of litter is produced annually, 258,081 of which comes from the four Lower Shore counties, according to the Maryland Department of Agriculture.
For years, medical experts have warned that chronic human exposure to arsenic could lead to certain forms of cancer.
The National Academies, which advises the federal government on a range of health and science issues, reported to Congress in 2001 "that the data indicate arsenic causes cancer in humans at doses that are close to the drinking water concentrations that occur in the United States."
Scientists and environmentalists have debated the impact of arsenic on water quality and pollution in coal burning states for several years. The meat industry's use of arsenic has received less attention, some researchers suggest.
Executives from Perdue Farms Inc. could not be reached for comment on the composition of their feed, though a company spokesman said roxarsone is used "industry-wide."
Claims of cancer link
In a small Arkansas town surrounded by farmland, a group of residents have filed a lawsuit against Alpharma Inc. -- the manufacturer of the feed additive 3-Nitro -- and several poultry companies that use the product, including Tyson Foods Inc. Roxarsone is an active ingredient in 3-Nitro, according to Alpharma's Web site.
John Baker, an Arkansas attorney, said he is representing 100 clients from the community of Prairie Grove who are sick or have had family members die from alleged exposure to roxarsone.
The first of several lawsuits was filed Dec. 16, a case that includes cancer survivors and the parents of four children who died from leukemia and brain cancer.
According to Baker, several residents in the town of 2,500 have been diagnosed with rare cancers that usually occur at a rate of one in a million.
"We've tested homes of clients and found this stuff there. This arsenic is airborne and is inhaled," he said.
The Arkansas Department of Health, however, came to a different conclusion. Health officials one year ago investigated and ruled that there is no evidence Prairie Grove residents suffer cancer rates at levels disproportionate to other parts of the state.
Unsatisfied with the department's findings, the plaintiffs hired their own investigators.
"We don't think their data is accurate," Baker said.
Poultry industry representatives defend the use of roxarsone, arguing that no research supports the claim that the feed additive is linked to cancer.
Richard Lobb, a spokesman for the National Chicken Council, an industry trade group, questioned the motives of the attorneys and their clients.
"This is totally without merit. They're hoping to get a big payoff. (Roxarsone) is FDA approved and I don't think there are any real scientific concerns," he said.
Poultry, regulations and courts
The Arkansas lawsuit is the latest in a flurry of recent legal activity directed against the poultry industry.
On Nov. 10, a federal judge in Kentucky during a pretrial motion made a ruling that some industry observers suggest could have far-reaching consequences.
U.S. District Judge Joseph McKinley ruled that Tyson Chicken Inc. -- a subsidiary of Tyson Foods -- shares responsibility with growers for reporting air pollution violations, rejecting arguments by officials for the poultry company that its contract chicken growers are solely responsible for the environmental problems that stem from their farm operations.
The lawsuit filed by the Sierra Club against Tyson resembles the debate in Maryland over whether integrators should be held responsible for nutrient management practices on their growers' farms.
Theresa Pierno, vice president of environmental protection at the Chesapeake Bay Foundation, has said the Kentucky case could serve as the legal precedent to file similar claims against Maryland corporations.
William Satterfield, executive director of the regional trade group Delmarva Poultry Industry Inc., said his group keeps corporations here informed of legal action in other parts of the country.
"Certainly these things are a concern. If suits can be filed in one state they can be filed in another," he said.
In recent years, opposition against the industry has grown, Satterfield said.
"More and more people are challenging our industry and the way we feed the world ... We used to do more work on growing issues, now we're dealing with more of these external issues," he said.
Water, soil and cancer rates
Cancer rates on the Lower Shore are among the highest in Maryland and also exceed national averages, according to the American Cancer Society and regional medical experts.
Somerset County is a national leader, with a cancer death rate of 267 cases for every 100,000 people.
Nationwide, cancer deaths claimed 206 people out of every 100,000 from 1994 to 1999. Rates in Wicomico and Worcester counties also surpassed national and state averages with a statistical measurement of 233 deaths and 229 deaths per 100,000 people.
Health care experts on the Lower Shore have long debated why the rates here are so high, providing more questions than answers.
Explanations have ranged from poor eating habits on the Lower Shore to high numbers of people without health insurance and environmental factors.
In 2001, the National Academy determined that enough evidence existed to draw the conclusion that arsenic rates commonly found in the country's water supply were enough to lead to some forms of cancer. The findings came at a time when President Bush was working to repeal a Clinton administration proposal to reduce the allowable amount of arsenic in drinking water from 50 micrograms per liter to 10 micrograms per liter, which is the health standard used by the European Union and World Health Organization.
In March 2001, the Environmental Protection Agency withdrew the pending rule change, restoring the 50 micrograms standard.
During the political debate over arsenic limits, the Maryland Department of Environment commissioned a study of arsenic levels in all major aquifers on the Maryland Coastal Plain.
The results of the study, performed by the Maryland Geological Survey, are expected to be published this summer, project leader David Bolton said.
The data collected from wells and aquifers from the Upper Shore to the Lower Shore indicate that arsenic levels are normal.
"There is nothing to suggest arsenic levels are a problem in drinking water," Bolton said.
Tests on Eastern Shore wells in most cases showed arsenic levels of 2 micrograms per liter -- well below the legal limit of 50 micrograms and below the 10 micrograms levels recommended by the EPA under the Clinton administration, he said.
In some aquifers found deep underground in Dorchester, Queen Anne's and Talbot counties, arsenic registers at a higher level than other parts of the coastal plain.
Bolton said levels as high as 42 micrograms per liter were found in Dorchester, still below the legal limit.
However, there is no evidence to show the practice of spreading arsenic-laced chicken litter on farmland is not responsible for Dorchester's higher arsenic levels, according to Bolton.
In addition to being an industrial byproduct, arsenic exists naturally in the environment. High concentrations are usually found in mining, copper smelting and coal burning states.
But natural causes explain the higher arsenic concentrations found in some parts of the shore, including Dorchester County, Bolton said.
Less information is available on how arsenic in litter affects soil and surface water.
According to the researchers with the U.S. Geological Survey, one chicken excretes about 150 milligrams of roxarsone in a 42-day growth period. Litter collected during that period contains between 30 to 50 milligrams per kilogram of total arsenic, according to the report.
On the Delmarva Peninsula, it means between 20 and 50 metric tons of arsenic are introduced to the environment annually by chicken farmers.
The U.S. Geological Survey is attempting to find out what impact the poultry industry's use of arsenic has on soil and water environments on Delmarva.
Silbergeld said she expects a better understanding of the health effects of roxarsone to emerge once scientists begin exploring the issue.
"We who've been doing research (on the poultry industry) really haven't looked at this," she said.
In the meantime, Gov. Robert Ehrlich has recommended that Maryland should explore alternative uses for poultry manure to help the industry and the environment.
Chicken litter could potentially serve as an alternative energy source, something Silbergeld says could be dangerous.
"If the levels of arsenic in waste are significant, burning it would be the worst thing to do," she said.
Reach John Vandiver at 410-845-4656 or firstname.lastname@example.org.
source: http://www.dailytimesonline.com/news/stories/20040104/localnews/163756.html 4jan04