Sewage Testing Helps Track Illicit Drug Use

A screening test provides evidence of illicit drug abuse in drug residues and metabolites excreted in urine and flushed toward municipal sewage treatment plants.

Past estimates of illicit drug abuse in a community were based largely on surveys in which children and adults were asked about their use of illegal drugs. Investigators knew that some participants in surveys were not giving honest replies, with individuals being reluctant to admit breaking the law.

The sewage screening approach could provide a fast, reliable, and inexpensive way to track trends in drug use at the local, regional, or state levels while preserving the anonymity of individuals, according to scientist Jennifer Field, Ph.D., an environmental chemist at Oregon State University (Corvallis, OR, USA), who works with colleagues at Oregon State University and at the University of Washington (Seattle, WA, USA).

Dr. Field reported that the screening method under development in her lab improves upon the utility of the laboratory tools currently used to identify traces and metabolites of drugs in such studies. Her lab is refining the technique to verify its accuracy for extremely low concentrations, the order of a few ng/l. Calculations of drug use based solely on byproducts found in water supplies, especially at low levels, can be subject to error, Dr. Field said. To address this issue, her lab is working to identify common indicators, or biomarkers, such as caffeine or nicotine that can be used to sharpen their calculations.

"A lot of things contribute to the flow in wastewater, including agricultural and industrial processes. By linking our illicit drug measurements to biomarkers related to measurable human activities, we could compensate for differences in flows that aren't related to human excretion,” said Dr. Field.

The screening test was described at the 234th national meeting of the American Chemical Society, which took place in Boston (MA, USA) in August 2007.


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University of Washington