Pipe Dreams: Tapping into the Health Information in Our Sewers.

Abstract

Most of us have an attitude of “flush it and forget it,” but to scientists like Rolf Halden, our waste is a bonanza of valuable information on population-level chemical exposures. Halden is an environmental scientist at Arizona State University’s Biodesign Institute, where he maintains the National Sewage Sludge Repository—a collection of hundreds of samples of raw sewage and sludge collected from more than 200 sites around the United States.1 The sample bottles are filled with a brownish-black slurry derived from raw sewage, “so it has everything that is flushed down the toilet,” says Arjunkrishna Venkatesan, a postdoctoral research associate on Halden’s team. “If you collect samples from sewerage manholes, sampling equipment is going to get clogged, and you’re going to have hair, condoms, and all sorts of stuff.” The laboratory staff filter out most of those solids, then freeze the samples for storage. The emerging field of sewage chemical-information mining is taking advantage of a readily available yet underappreciated resource: the untreated waste flowing under our feet and the biosolids remaining after treatment. It turns out that sewage and sewage ... As disgusting as the samples may be, the repository is helping to open up a field known broadly as sewage chemical-information mining (SCIM). This field is using the sewage destined for wastewater treatment plants as a medium for chemical exposures within a community, exposures that are impractical to measure by other means. Other studies are looking at sewage sludge (the solids that remain after wastewater treatment) for information on chemicals that can accumulate in the human body. Still another approach, known as BioSCIM, measures biomarkers in sewage as a way to assess the overall health status of communities. SCIM initially took off in 2001 when scientists hypothesized they could measure the metabolites of illicit drugs like cocaine, heroin, and methamphetamine in untreated wastewater collected from city sewers.2 This particular application of SCIM was originally known as “sewage epidemiology.” The success of this technique has been tested in Europe3,4 and most recently provided per capita estimates of drug usage in cities including Antwerp, Stockholm, and London.5 Now sewage epidemiology is being applied to substances beyond illicit drugs. Since 2010 Halden has published nearly 50 papers on the subject. One study calculated per capita chemical consumption and, based on levels found in sewage sludge, estimated exposure to more than 70 pharmaceuticals and other chemicals used in consumer products.6 “This work lets us put a finger on the chemical pulse of a nation,” Halden says.