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Aberdeen American News (SD)
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Wednesday, July 3, 2002
EPA using outdated technology in assessing sewage sludge risk
By John Heilprin
Associated Press Writer
The government is using outdated science in assessing the health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. 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. 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.