(Wow, seems like are money could go to something better. Kind of big brother as well, tracking what we do through are waste)
Flushing Out a Record of Local Drug Use
Researchers have perfected a method of taking a small sample of incoming sewage at a water treatment plant and extracting the record of local drug use
By David Biello
In the latest attempt to crack down on illegal drug use, scientists say they can determine the extent and pattern of illicit drug use—from marijuana to heroin to cocaine—by sampling sewage and extracting the telltale by-products.

For example, cocaine is snorted, does its brain-altering business and then passes through the liver and the kidneys on its way out of the body. It emerges in urine as benzoylecgonine and, as that urine travels from toilet to treatment plant, it mixes with a host of other by-products of human activity.

Environmental analytical chemist Jennifer Field of Oregon State University and her colleagues, using an automated system they developed, test small samples automatically collected at wastewater treatment plants over a 24-hour period. Solids are centrifuged out and the sewage sample then travels at high pressure through a machine that chemically separates the various compounds of interest chemically, such as benzoylecgonine. By measuring the relative mass of the various residual chemicals, the chemists can then identify what specific drugs have been recently used in that community.

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