BOSTON -– A team of researchers has developed an automated monitoring method that makes it possible to detect traces of drugs, from cocaine to caffeine, in municipal wastewater and to monitor the patterns of drug use in entire communities.
Their findings were reported today at the American Chemical Society meeting in Boston.
Oregon State University chemist Jennifer Field described methodologies that she developed with colleagues Daniel Sudakin, an OSU toxicologist, Caleb Banta-Green, a drug epidemiologist at the University of Washington, and Aurea Chiaia Hernandez, an OSU graduate student.
The method could provide a drug surveillance tool to help public health and law enforcement officials identify patterns of drug abuse across municipalities of all sizes.
The presence of both pharmaceutical and illicit drugs in municipal wastewater has been known for several years, beginning with groundbreaking studies in Europe that tracked the presence of drugs in sewage and river water. Field and her colleagues have developed new methods of chemical analysis so that detection is possible from very small samples taken automatically over a 24-hour period from wastewater as it enters a treatment plant.
“It’s like a very diluted urine sample collected from an entire community,” Field said.
The analysis can detect the presence of a long list of illicit drugs, from methamphetamine to Ecstasy and other markers of human presence such as caffeine and cotinine, a break-down product of nicotine from cigarette smoke.
Although wastewater is often tested for contaminants after it is treated as a measure of potential environmental impact, this new approach tests sewage as it enters a wastewater treatment plant, before it is treated, to get a profile of the drugs being used in the community.
“This method is most useful for drug surveillance at the community level,” Field said.
Finding patterns of drug consumption in the wastewater can alert municipalities to problems that occur in particular communities or at particular times. This may be useful for tracking such things as the geographic patterns of methamphetamine use.
Oregon and Washington have experienced a three-fold increase in meth-related deaths in recent years, according to Banta-Green, who is a research scientist at UW’s Alcohol and Drug Abuse Institute.
But translating a tiny trace of drug into the number of individual users is problematic, according to the researchers, requiring many assumptions and variables such as dose, frequency, excretion rates, and whether the drug was ingested or inhaled.
“Wastewater analysis is a more powerful indicator at the community level,” Field said. “We are interested in the 'community load' of drugs, so we want to take samples as close to the urinal as possible without violating the privacy of individuals.”
The researchers tested wastewater from ten mid-sized municipalities, calculating the concentrations of individual drugs and using the volume of wastewater flowing into the treatment plant and the municipal population in order to estimate the community load of each drug.
According to Sudakin, who is both a physician and a toxicologist at OSU, the value of such data multiplies when entered into a database of spatial statistics on drug use. When the chemical analysis of wastewater is added to geographic data on, for example, methamphetamine poisoning incidents, meth-related deaths and meth lab seizures, patterns emerge that may help officials develop preventive interventions.
Even in their preliminary study, the researchers found patterns over time of drug occurrence in wastewater, with higher concentrations of recreational drugs (such as cocaine) on weekends. They found no change in concentrations of either prescription drugs or methamphetamines in their samples over time, which suggests more consistent use of both.
The researchers’ wastewater analysis demonstrates that the new methodology can be applied cost-effectively on a larger scale to collect data from communities across Oregon or any other state. And because the data can be collected daily, weekly, or monthly, they represent a real-time measure that provides communities with more opportunity for prevention and intervention.
Up to now, most conventional studies of community-level drug abuse have been conducted in a few very large cities. This new method, because it is automated and relies on tiny samples from municipal treatment plants, can be used in more and smaller communities, making it possible to portray patterns of drug use across much more of the population.
“The methods allow us to better understand the geographic differences in the abuse of drugs (particularly methamphetamine) within the state of Oregon,” Sudakin said. “We hope that these tools may be useful in identifying communities at risk and developing preventive interventions to reduce the adverse impact of methamphetamine throughout the state.”