Of the many privileges enjoyed by those of us living in modern, industrialized nations, there is none so underappreciated, perhaps, as flushing. Americans produce an estimated eight million tons of sewage waste per year, yet most of us don't know (and don't care to know) where it goes, so long as it disappears from our homes swiftly and efficiently.
Figuring out what to do with this constant output from its citizens has flummoxed the greatest civilizations, and ours is no exception. We incinerate it, bury it, and have even flushed it into rivers. Until a congressional ban took effect in 1991, coastal cities such as New York and Boston even dumped their sewage straight into the Atlantic. Around the same time, as the recycling craze swept the nation, the Environmental Protection Agency (EPA) decided to promote another disposal method: "recycling" sewage sludge as
fertilizer. (One 1994 EPA brochure extolling the "benefits of biosolids" shows the grounds of Mt. Vernon, abundantly green thanks to applications of sludge.) Less than a decade later, more than half of all human sludge generated in the United States is sprayed on everything from cropland to public parks.
But what the EPA touted as an environmentally sound solution to a messy problem has left the agency itself caught in a mire. Land application of sludge is being blamed for the deaths of a 26-year-old man in New Hampshire and two boys in Pennsylvania, as well as scores of illnesses across the country. The EPA is now trying to cope with a chorus of criticism over the practice. A recent National Academy of Sciences report cited "persistent uncertainty" about the health effects caused by the EPA's sludge policies, and the agency's own Office of Inspector General found that the "EPA cannot assure the public" that its current regulations for handling and applying sewage to fields "are protective of human health and the environment." An assistant administrator at the agency, Paul Gilman, was forced to admit on CBS Morning News last October, "I can't answer it's perfectly safe; I can't answer it's not safe," about a practice the agency once said was proven safe by "hundreds of studies."
It's true that sludge offers a smorgasbord of nutrients to growing plants. But it's also true that today's raw sewage is more like hazardous waste, often containing toxic heavy metals such as cadmium and lead, not to mention the millions of bacteria, viruses, and other disease-causing organisms that are inevitable when you mix the biological waste of thousands of strangers.
The EPA's rules limit the amounts of nine toxic metals that can be in sludge intended for land application and divide that sludge into two classes. Class A sludge can be applied anywhere, from city parks to backyards, because it has been subject to one of six pathogen-killing regimens; Class B sludge is less intensively treated, and for that reason is restricted to land where direct human contact is less frequent, such as farm fields.
Critics, however, contend that when these germy particles of sludge become airborne -- for instance, when sludge is sprayed on fields in windy conditions -- nearby residents can inhale them and become sick. The EPA counters that there's no evidence to support these claims. But as the National Academy of Sciences, the EPA's inspector general, and a number of others point out, the agency hasn't funded enough studies to prove that people aren't getting sick as the result of a policy that the EPA has spent 10 years and millions of dollars promoting as safe.
Earlier this year, the EPA finally relented and announced that it was calling for more studies on the public-health effects of its sludge regulations, but a number of scientists, such as Ellen Z. Harrison, director of the Cornell Waste Management Institute, say the EPA can't be trusted to foster objective science in this area. Her fears appear justified. David Lewis, a microbiologist who worked at the EPA for 31 years, published a peer-reviewed 2002 study in Environmental Science and Technology demonstrating that pathogens could easily remain undetected in treated sludge. Lewis says he was harassed and finally fired from the agency last May. The Labor Department is investigating whether the EPA violated federal whistleblower laws by dismissing him.
Lewis is blunt about his skepticism of the agency's call for studies. At a February Capitol Hill hearing on the role of science in shaping public policy, he charged that the "EPA has corrupted the scientific peer-review process in order to support certain political agendas and further the agency's self-interest." He points to the cozy relationship that exists between the EPA and the Water Environment Research Foundation, a nonprofit partly funded by companies in the sludge-hauling business. The group typically receives $4 million to $8 million a year from the EPA and, not surprisingly, produces studies that tend to tout sludge's benefits. "They're going to funnel funding to scientists who've supported them on sludge," Lewis predicts. "The outcome is a foregone conclusion."
-- Jason Best