In a never-ending battle, another industry standard is being
brought under fire on its scientific basis. A new report from the National
Academies' National Research Council states the U.S. Environmental
Protection Agency's (EPA) standards that govern using treated sewage
sludge (biosolids) on soil are based on outdated science.
This time though, it was the EPA who asked the National
Academies to convene a committee to conduct an independent evaluation of the
technical methods and approaches used to establish the chemical and pathogen
standards for biosolids. They specifically were to focus on health protection.
"There is a serious lack of health-related information
about populations exposed to treated sewage sludge," said Committee Chair
Thomas A. Burke, professor, Department of Health Policy and Management, Johns
Hopkins University Bloomberg School of Public Health.
Under a 1993 Clean Water Act rule (Part 503), biosolids can
be applied to land if it is treated to limit concentrations of certain
chemicals and reduce disease-causing pathogens. These biosolids are applied to
agricultural or other lands to improve the properties of the soil.
Approximately 60 percent of the 5.6 million dry tons of sewage sludge disposed
of annually in the United States are land applied.
According to the committee, methods for assessing the health
risks caused by exposure to chemicals have evolved substantially since the 1993
rule was established. In addition, EPA used an unreliable 1988 survey to
identify chemicals to regulate and since then new chemicals have been
identified as concerns. A new survey and revised risk assessments were
However, the committee agreed with EPA's general
approach for regulating pathogens. EPA established requirements to reduce
pathogens by treatment or a combination of treatment and use restrictions. The
report found no documented scientific evidence of the EPA's standards
failing to protect public health.
The report did suggest that the agency use new
pathogen-detection technology to ensure that treatments are available. It also
suggested that EPA increase its efforts to ensure that companies producing
biosolids meet the regulatory requirements to remove or neutralize chemicals
The fact is just 30-years ago, thousands of American cities
dumped their raw sewage directly into our nation's rivers, lakes and
bays. Now, only biosolids that meet the most stringent standards spelled out in
the Federal and state rules can be approved for fertilizer.
I remember when I was a kid, my family loaded up the car
trunk with untreated cow manure from a relative's farm in downstate
Illinois and drove back to Chicago so we could put it in the garden. Obviously,
waste treatment has come a long way since then. As with many EPA rules, a little
reassessment to make sure that standards are still based on current data might
be a good idea.