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Columns::October 7, 2002
Pillar to pillar: J.W. Fanning Building will be dedicated on Oct. 10
Former education professor leaves UGA $1.7 million
D.W. Brooks Award winners announced
Report: Agreements insufficient to contain weapons of mass destruction
Study: Moms in poor, rural areas can rise above their surroundings
Tricia Kalivoda is named associate VP designee for public service and outreach
UGA welcomes new faculty
Sitting in judgment
Take it from the top
Campus News
An ill wind
Researchers link human illness to sludge fertilizer
By Kim Carlyle
kosborne@uga.edu
Burning eyes, burning lungs, skin rashes and other symptoms of illness have been found in a study of residents living near land
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| Limed sewage sludge is visible at the edge of a wetland in DeSoto County, Fla. (Photo by Mari Hollingsworth) |
fertilized with Class B biosolids, a byproduct of the human-waste treatment process.
The study, the first reporting this link to be published in a medical journal, was co-authored by David Lewis, a UGA research microbiologist also affiliated with the U.S. Environmental Protection Agency’s National Exposure Research Laboratory; David Gattie, assistant professor of agricultural engineering in UGA’s College of Agriculture and Environmental Sciences; Marc Novak, a research technician with UGA’s School of Marine Sciences; Susan Sanchez, assistant professor of veterinary medicine at UGA; and Charles Pumphrey, a physician from Prime Care of Sun City in Menifee, Calif. The research was published earlier this year in the British medical journal BMC Public Health.
Researchers found that affected residents lived within approximately one kilometer (0.6 miles) of land-application sites and that they generally complained of irritation after exposure to winds blowing from treated fields. Staphylococcus aureus infections, which commonly accompany diaper rash, were found in the skin and respiratory tracts of some individuals. Approximately 25 percent of the individuals surveyed were infected, and two died.
The 54 individuals surveyed lived near 10 land-application sites in Alabama, California, Florida, New Hampshire, Ohio, Ontario, Pennsylvania and Texas. S. aureus is commonly found in the lower human colon and tends to invade irritated or inflamed tissue.
“The EPA did not consider S. aureus to be a significant public health risk even though it is a leading cause of hospital-acquired infections and is commonly found in sewage,” says Lewis. “When approving sludge for use as a fertilizer, EPA looked at chemical and pathogen risks separately, without considering that certain chemicals could increase the risk of infection.”
Chemicals such as lime, which is added during sludge processing, can irritate the skin and respiratory tract and make people more susceptible to infection, according to Lewis. Another article by Lewis and Gattie dealing with pathogen risks from sludge was recently published in the American
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David Gattie
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Chemical Society journal Environmental Science and Technology.
Approximately 60 percent of an estimated 5.6 million tons of dry sludge is used or disposed of annually in the United States. Though modern treatment can eliminate more than 95 percent of the pathogens, enough remain in the concentrated Class B sludge that leaves treatment plants to pose a health risk, according to Lewis and Gattie.
In an independent report released almost simultaneously with the Lewis and Gattie article, the National Research Council of the National Academy of Sciences concluded that there may be public health risks from using processed sewage sludge as a commercial fertilizer.
The NAS report, “Biosolids Applied to Land: Advancing Standards and Practices,” cites growing allegations that exposure to Class B sludge, the most common form, is causing illnesses and sporadic deaths among residents. The report concludes that certain types of exposure, such as inhalation of sludge particles, “were not adequately evaluated” previously and no work has been done on risks from mixtures of pathogens and chemicals found in sludge. In 1989, an EPA study found 25 groups of pathogens in sludge, including bacteria such as E. coli and
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David Lewis
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salmonella; viruses, including hepatitis A; intestinal worms; harmful protozoa; and fungus.
Sludge also includes traces of household chemicals poured down drains, detergents from washing machines, heavy metals from industry, synthetic hormones from birth control pills, pesticides, and dioxins, a group of compounds that have been linked to cancer.
Fertilization of land with processed sewage sludge, or “biosolids,” has become common practice in western Europe, the United States and Canada. Local governments, however, are increasingly restricting or banning the practice as residents have reported adverse health effects.
“Most people are not aware this is going on in the United States,” says Gattie. “Most people don’t realize that a concentrated sludge of waste products is being processed into a cheap commercial fertilizer and applied to fields near our homes. ‘Biosolids’ does not connote ‘sewage’ to most people.”
Gattie notes this practice became more common after ocean dumping of sewage was prohibited.
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