Which city uses more cocaine: Los Angeles or London? Is heroin a big problem in San Diego? And has Ecstasy emerged in rural America?
Environmental scientists are beginning to use an unsavory new tool -- raw sewage -- to paint an accurate portrait of drug abuse in communities. Like one big, citywide urinalysis, tests at municipal sewage plants in many areas of the United States and Europe, including Los Angeles County, have detected illicit drugs such as cocaine, methamphetamine, heroin and marijuana.
Law enforcement officials have long sought a way to come up with reliable and verifiable calculations of narcotics use, to identify new trends and formulate policies. Surveys, the backbone of drug-use estimates, are only as reliable as the people who answer them. But sewage does not lie.
Since people excrete chemicals in urine and flush it down toilets, measuring raw sewage for street drugs can provide quick, fairly precise snapshots of drug use in communities, even on a particular day.
The results have been intriguing: Methamphetamine levels in sewage are much higher in Las Vegas than in Omaha and Oklahoma City, Okla. Los Angeles County has more cocaine in its sewage than several major European cities. And Londoners apparently are heavier users of heroin than people in cities in Italy and Switzerland.
"Every sample has one illicit drug or another, regardless of location," said Jennifer Field, an environmental chemist at Oregon State University who has tested sewage in many U.S. cities. "You may see differences from place to place, but there's always something."
The new practice of testing sewage has illuminated an environmental threat: Many urban waterways around the world are contaminated with low doses of cocaine and other illicit drugs from treated sewage.
So far, this "sewage forensics" or "sewage epidemiology" has not been widespread. Treatment plants do not regularly monitor sewage for street drugs. The Environmental Protection Agency is planning to add illicit drugs to the array of substances that could be monitored daily at treatment plants.
Unlike prescription drugs and personal care products, which are a hot topic in environmental contamination, illicit drugs have long been below the radar.
Christian Daughton, chief of environmental chemistry at the EPA's National Exposure Research Laboratory, first proposed the tests in 2001.
