- Burning eyes, burning lungs, skin rashes and other symptoms
of illness have been found in a study of residents living near land fertilized
with Class B biosolids, a byproduct of the human waste treatment process.
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- This study is the first linking adverse health effects
in humans to the land application of Class B biosolids to be published
in a medical journal. It was co-authored by David Lewis, a UGA research
microbiologist also affiliated with the U.S. Environmental Protection Agency
(EPA)'s National Exposure Research Laboratory; David Gattie, assistant
professor of agricultural engineering at the University of Georgia's College
of Agricultural and Environmental Sciences; Marc Novak, a research technician
at 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 article appeared this month in
the British medical journal, BMC Public Health.
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- Researchers found that affected residents lived within
approximately one kilometer (0.6 miles) of land application sites and generally
complained of irritation after exposure to winds blowing from treated fields.
A prevalence of Staphylococcus aureus infections, a condition commonly
accompanying diaper rash, was 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.
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- "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," said 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."
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- 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. The American Chemical
Society recently published another article on pathogen risks from sludge
by Lewis and Gattie in their journal Environmental Science Technology.
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- Though modern treatment can eliminate more than 95 percent
of the pathogens, enough remain in the concentrated Class B sludge leaving
treatment plants to pose a health risk, according to Lewis and Gattie.
-
- On July 2, the National Research Council of the National
Academy of Sciences (NAS) concluded that there may be public health risks
from using processed sewage sludge as a commercial fertilizer. Approximately
60 percent of an estimated 5.6 million tons of dry sludge is used or disposed
of annually in the United States.
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- The NAS report entitled "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 salmonella; viruses, including hepatitis A; intestinal worms;
harmful protozoa; and fungus.
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- 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 in response to residents reporting
adverse health effects.
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- "Most people are not aware this is going on in the
U.S.," said 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." He notes this practice has become more common after
ocean dumping of sewage was prohibited.
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- Note: This story has been adapted from a news release
issued by University Of Georgia for journalists and other members
of the public. If you wish to quote from any part of this story, please
credit University Of Georgia as the original source. You may
also wish to include the following link in any citation:
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- http://www.sciencedaily.com/releases/2002/07/020730075144.htm
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