Sewage as a Measure of Society's Drug Use
All kinds of people use illegal drugs, all over the country -- in urban, suburban, ex-urban, and rural areas. Yet our imperfect methods for gauging community drug use disproportionately represent cities and often leave out the highest-risk populations, giving a skewed picture of who uses what types of drugs where.
The answer, oddly enough, may reside in shit. After all, everything that comes in must come out, so using human waste as a measure of society's health makes sense.
Drug epidemiologists are particularly excited by a study published last year in the journal Addiction which tested untreated wastewater in municipal plants throughout the state of Oregon for traces of cocaine, methamphetamine, and Ecstasy.
The Oregonstudy is not the first to test wastewater for drugs, but it's the first to use the methodology to spatially map drug prevalence. And its most exciting result is likely that it shows just how geographically widespread drug use is.
Researchers studied wastewater samples from 96 municipal water treatment facilities throughout Oregon. These represented one-day snapshots of 65 percent of the state's population's sewage. The results show that drugs are found in all sorts of communities -- everywhere from small, rural towns to suburbs and inner cities.
The emergence of drug use specific to small towns and rural areas -- propelled by the use of meth and prescription opiates -- has cemented the geographic and socio-economic universality of illicit drug use. The Oregon data showed more meth was detected in rural areas than in urban cities, while higher traces of cocaine and Ecstasy were found in urban locations.
To folks who study drug epidemiology carefully, these results could prove revolutionary. Currently, we rely on two surveillance systems that are biased toward urban areas. One is the DAWN Program, which monitors drug-related visits to hospital emergency rooms and drug-related deaths investigated by medical examiners, and another is the Arrestee Drug Abuse Monitoring program, a voluntary survey and urinalysis of arrestees.
We also depend on the Treatment Episode Data Set, which pulls drug treatment data from across the country but relies mostly on data from public facilities and is, by its very nature, a lagging indicator. Finally, the big federal surveys -- namely the National Survey on Drug Use and Health -- suffer from response bias and miss many of the folks who are most likely to be using drugs, such as the homeless, hospitalized, and imprisoned.
"Small-town drug usage is a big mystery," says John Newmeyer, a social psychologist in San Francisco who has worked as a drug counselor and first thought of testing sewage water 15 years ago. "So is usage of certain drugs, like MDMA [or Ecstasy] that don't have negative indicators -- like a high number of overdoses or arrests -- and which are very hidden."
But wastewater carries the metabolites of everything you ingest -- so a more accurate idea of the prevalence of drugs like Ecstasy will now be possible. In addition, sewage testing eliminates the urban skew, as the vast majority of the country's waste flows to sewage systems rather than to individual septic tanks. And municipal wastewater includes the high-risk populations that are left out of the other data because their waste flows into the same sewage treatment facilities.
As a result, Caleb Banta-Green, a co-author of the study, said another plus is that "you can measure apples to apples across places. You can't compare places if you're not measuring them in the same way."
But the methodology has its limitations. Though researchers testing the waters of the Po River in northern Italy concluded in 2005 that 1.4 million young adults living in the Po River Basin's watershed were consuming about 40,000 doses of cocaine a day, Banta-Green says such back-calculations are "extrapolations that are speculative at best." The methodology, as it stands right now, he says, can only really accurately measure traces of drugs in certain geographic locations, so you can compare drug trace levels in different areas, but you can't tell how many people are using drugs and at which rate.
Additionally, the chemistry behind the wastewater drug tests does not allow scientists to pinpoint who metabolized which drugs. After all, "your waste product is a chemical, while your DNA is a biological molecule," Newmeyer told me. Because of this, waste cannot be tracked back to individuals, or even broken down to specific demographic groups, such as gender or race.
For all these reasons that make the method an ineffective way of tracing waste to specific drug users, Andrea Meyer, of ACLU's Oregon chapter, said she has no concerns regarding individual privacy, and adds that if harnessed for law enforcement purposes it would be a "poor use of resources."
But in the future, if the method catches on, communities could potentially be penalized. Bill Piper, the director of national affairs for the Drug Policy Alliance, told me that wastewater drug testing "might some day be used as a form of surveillance that would lead to increased arrests, the passage of more punitive laws or both."
The good and bad news, however, is that historically "there is little to no correlation between rates of drug use and drug arrests," Piper told me. "Some counties with high use rates have arrest rates lower than counties with low use rates."
Indeed, a study by the Justice Policy Institute shows what most determines drug arrests is not drug use or even crime, but how much a jurisdiction spends on law enforcement. More funding "translates into more nonviolent drug law offenders behind bars instead of treatment," Piper said. For this reason, he is doubtful that more information will lead to smarter allocation of policing resources.
And then there is the issue of racial profiling -- and this is where the Oregon's study's methods could prove advantageous, if not in law enforcement then in public opinion and policy.
Currently, drug use by whites and blacks is about equal, but arrests of blacks -- and other minorities -- is much higher. If anything, the wastewater methodology will confirm the widespread geographic use of illegal drugs. If people are made aware that drug use is not relegated to poor, inner-city minorities, it may help demystify drugs and their users to many who in the past have cast an ignorant eye at the drug war. This, in turn, could lead to smarter policy regarding treatment and prevention relating to drugs.
Of course, it's just as likely to lead to crazy, alarmist freak-outs by stalwart prohibitionists who have underestimated just how ubiquitous drug use is in our society.
But Banta-Green, a drug epidemiologist, remains hopeful that in the long-run, better information about drug use will be a public health win.
The Oregon study shows "drug use is everywhere," he said. "So it's really up to everyone to engage about it."
