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Panel: Old rules used to gauge sewage sludge risks
Wednesday, July 3, 2002
By JOHN HEILPRIN Associated Press writer
WASHINGTON — The government is using outdated science in assessing the health risks of more than 3 million tons of sewage sludge used as fertilizer each year, a panel of scientists said Tuesday.
When the Environmental Protection Agency set standards in 1993 on the use of
“biosolids” for treating soil, it used an unreliable 1988 survey to identify
hazardous chemicals in sewage sludge from wastewater treatment plants, said the
National Research Council panel.
Since then, the panel said, the technology for detecting pathogens and the
methods for assessing health risks posed by exposure to chemicals in the sludge
have developed significantly.
“There is a serious lack of health-related information about populations exposed
to treated sewage sludge,” said the panel’s chairman, Thomas A. Burke, a health
policy and management professor at Johns Hopkins University’s Bloomberg School
of Public Health in Baltimore.
The panel’s 270-page report, which had been requested by EPA, found no
documented scientific evidence of the EPA’s standards failing to protect public
health. But it said the agency needs to do more scientific work so it can
“reduce persistent uncertainty” about the risks to people from exposure to
chemicals and disease-causing pathogens in sludge used as fertilizer.
The EPA hasn’t done a substantial reassessment to determine if its standards are
supported by current scientific data and risk-assessment methods, the panel
said, noting that it had made a similar recommendation in 1996.
The agency also was faulted for continuing to rely heavily on a 1990 survey that
contained sampling “inconsistencies” and used reporting methods that “undermined
the reliability of the data” instead of conducting new scientific studies.
EPA officials had no immediate comment. Adam Krantz, a spokesman for the
Association of Metropolitan Sewerage Agencies, a trade group, said “each step
has indicated a lack of health risk” as the EPA studies and regulates sewage
sludge.
“Everyone wants to make this into some gigantic crisis situation when there’s
not a sufficient degree of specific evidence” that sewage sludge poses a danger,
Krantz said. “A crisis simply doesn’t exist.”
After sewage sludge is treated to limit concentrations of some chemicals and
reduce pathogens, it is commonly known as biosolids, which can be applied as
fertilizer to farms, forests, parks, golf courses, lawns and home gardens.
About 5.6 million tons of sewage sludge are used or disposed of each year in the
United States, and 60 percent of it is used as fertilizer. The rest is buried in
landfills or incinerated. Dumping sewage into the ocean was banned in 1992.
In February, a report by the EPA’s inspector general found the government has
done too little research to ensure humans are safe from the viruses, bacteria
and toxins in the sludge.
Mike Cook, who was then the EPA’s director of wastewater and management, said at
the time that the agency had significantly cut money and staff for sludge
oversight to deal with other clean-water issues. Cook, who has since transferred
to another EPA office, said the agency was setting up a program to review
compliance of sludge makers and users and to review concerns in local
communities, ranging from odors to illnesses.
EPA regulates nine inorganic chemicals in biosolids and is considering adding to
its oversight a class of organic chemicals known as dioxin, which is released as
an air pollutant and settles in grass and feed, which becomes fat in livestock
and poultry.
The National Research Council is a part of the National Academy of Sciences, an
independent agency chartered by Congress to provide advice to the government on
scientific issues.
On the Net:
National Research Council:
http://www.nationalacademies.org/nrc/
Environmental Protection Agency:
http://www.epa.gov/owm/mtb/biosolids/index.htm
Association of Metropolitan Sewerage Agencies:
http://www.amsa-cleanwater.org