Research Estimating Community Drug Abuse by Wastewater Analysis Ettore Zuccato, Chiara Chiabrando, Sara Castiglioni, Renzo Bagnati, and Roberto Fanelli Department of Environmental Health Sciences, Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy BACKGROUND: The social and medical problems of drug abuse are a matter of increasing global concern. To tackle drug abuse in changing scenarios, international drug agencies need fresh methods to monitor trends and patterns of illicit drug consumption. OBJECTIVE: We tested a sewage epidemiology approach, using levels of excreted drug residues in wastewater, to monitor collective use of the major drugs of abuse in near real time. METHODS: Selected drug target residues derived from use of cocaine, opiates, cannabis, and amphetamines were measured by mass spectrometry in wastewater collected at major sewage treat- ment plants in Milan (Italy), Lugano (Switzerland), and London (United Kingdom). The amounts of drug residues conveyed to the treatment plants, reflecting the amounts collectively excreted with urine, were used to estimate consumption of the active parent drugs. RESULTS: Reproducible and characteristic profiles of illicit drug use were obtained in the three cities, thus for the first time quickly revealing changes in local consumption (e.g., cocaine consump- tion rose significantly on weekends in Milan). Profiles of local drug consumption based on waste- water measurements are in line with national annual prevalence estimates. CONCLUSIONS: Patterns and trends of drug abuse in local communities can be promptly monitored by this tool, a convenient new complement to more complex, lengthy survey methods. In principle, searching the sewage for excreted compounds relevant to public health issues appears to have the potential to become a convenient source of real-time epidemiologic information. KEY WORDS: amphetamines, cannabis, cocaine, drug residues, illicit drugs, mass spectrometry, opiates, sewage epidemiology, urinary metabolites. Environ Health Perspect 116:1027-1032 (2008). doi:10.1289/ehp.11022 available via http://dx.doi.org/ [Online 1 May 2008] Official figures for the prevalence and occur- rence of drug abuse in different countries are currently obtained from population surveys integrated with crime statistics, medical records, and drug production and seizure rates [European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) 2006; United Nations Office of Drugs and Crime (UNODC) 2007a]. These statistical tools give a useful general picture of drug abuse, but estimates of consumption rates and drug use prevalence may be inaccurate, as most of the information is obtained from the consumers themselves. Moreover, because data collection and analysis are time consum- ing, current methods cannot offer frequently updated results to quickly detect changing patterns, and it is not easy to compare results between local communities (EMCDDA 1997). As recently recommended by the Commission of Narcotic Drugs of the United Nations (UNODC 2007b), novel approaches are needed not only to provide more realistic and comparable estimates of illicit drug consumption in different commu- nities, but also to detect changes in drug abuse patterns rapidly. We tested a sewage epidemiology strategy to monitor patterns and trends of commu- nity-wide illicit drug use. The idea of using drug monitoring at sewage treatment plants (STPs) to assess collective drug consumption was