Wastewater Drug Mapping

Wastewater Drug Mapping

Testing wastewater for drugs may help scientists track regional changes in drug abuse.


A city-wide drug test. I'm Bob Hirshon and this is Science Update.

If crystal meth use were on the rise in your town, the authorities would want to know. But it's hard to know that until it's painfully obvious. Now, epidemiologist Caleb Banta-Green of the University of Washington's Alcohol and Drug Abuse Institute is trying to keep tabs on drug use by testing the local wastewater.


The idea is to extend a urinalysis of a single person to find out what drugs they've consumed recently, to in fact getting a urinalysis for an entire city.

On a single day last year, Banta-Green's colleagues collected sewage from 96
Oregon towns. His team then tested the samples for traces of meth, coke, and ecstasy. Banta-Green says the resulting map jibed with what they already knew about regional drug-use patterns. This year, they're stepping it up by monitoring 20 cities on a weekly basis. I'm Bob Hirshon for AAAS, the Science Society.

Making Sense of the Research

When a patient has cancer, the earlier you catch it, the more treatable it is. The same could theoretically be said of drug abuse in an entire city or region. Unfortunately, it's very hard to catch subtle changes in drug abuse; after all, people don't usually report their own drug use to others, especially someone who's writing it down. As a result, widespread problems don't really become obvious until a lot of people start dying or getting hurt. 

This idea is to do the equivalent of a city-wide urine test, like those given to athletes and job applicants. Rather than ask every citizen to pee in a cup, they simply analyze municipal sewage for traces of drugs. If they can detect those traces, and they provide an accurate sense of how much the drug is being used, then monitoring changes in those chemicals can tip authorities off to increases (or decreases) in drug use.

In the pilot study, they approached 130 Oregon towns and asked them to provide average water samples across a single day. 96 towns participated. The researchers found that they were able to identify the chemical signatures of cocaine, methamphetamine, and ecstasy. More significantly, the levels of these chemicals, when adjusted for the size of the local population and the detectability of the drug, corresponded with what they already knew about regional drug use patterns. For example, they found meth everywhere, and its prevalence was about the same throughout the state. In contrast, they found cocaine in 80 percent of the cities and towns, and its usage rates were higher in urban areas than in rural areas. Ecstasy use was even more lopsided: it showed up in only half the towns, and was much more present in cities than in rural areas.

The technique has limitations. It can't reveal what types of people are using a particular drug, let alone which individuals (which would be an invasion of privacy anyway). Some drugs are much easier to detect than others, depending on how much of it gets excreted in an identifiable form, and how sensitive the chemical detectors are that look for it. The ultimate goal is to establish a baseline of drug use for a particular area, and then to watch for unexpected changes. If the levels of a particular drug go up, then law enforcement, schools, public health officials, and others could be put on an alert to look for signs of abuse.

Banta-Green's team had a grant from the National Institutes of Health to sample wastewater from 20 cities throughout 2009. Among the questions they tried to answer: How do drug use patterns change in one location over the course of the year? How often do you have to sample water to get good estimates? Are there particular days of the week, or particular seasons, that yield different results than others? Knowing the answers will make this technique much more effective at preventing drug epidemics.

Now try and answer these questions:

  1. What is the purpose of this experiment?
  2. How is this technique like an individual drug test? How is it different?
  3. What does the technique tell you that individual drug tests can't?
  4. What is the value of tracking changes in drug use in a geographic area? 
  5. What is the value of comparing different types of areas (urban versus rural, large versus small population) and their drug use patterns?

You may want to check out the August 7, 2009 Science Update Podcast to hear further information about this Science Update and the other programs for that week. This podcast's topics include: why mosquitoes prefer some people over others, the genetics of fine touch, how early poverty can haunt your health, and the science behind aromatherapy.

Going Further

For Educators

The National Institute on Drug Abuse site is an excellent resource for students, teachers, parents, and health professionals on the effects of drugs on the brain and body.

The Environmental Protection Agency's Water site features a collection of internal links to water information. Users can access information pertaining to ground and drinking water; water science; wastewater management; and wetlands, oceans, and watersheds.

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