González‐Mariño I, Baz‐Lomba J, Alygizakis N, et al. (2020). Spatio‐temporal assessment of illicit drug use at large scale: evidence from 7 years of international wastewater monitoring. Addiction. 115 (1): 109-120. doi: 10.1111/add.14767
Researchers used wastewater‐based epidemiology (WBE) to analyze the residue of amphetamine, methamphetamine, 3,4-Methylenedioxymethamphetamine (MDMA), benzoylecgonine (cocaine metabolite), and THC−COOH (cannabis metabolite), in the raw wastewater of 60 million people in 143 wastewater treatment plants in 120 cities in 37 countries, to determine illicit drug use trends over 7 years (2011–2017). Sampling occurred over 7 consecutive days in March or April each year. Researchers measured mass drug loads through an analytical chemistry technique (liquid chromatography–tandem mass spectrometry: precise enough to delineate dumping phenomena, differentiate between licit and illicit amphetamine use, and distinguish amphetamine residue from metabolized methamphetamine), and normalized loads by population size to calculate annual mean of daily load released per 1000 people (mg/1000 people/day). Central and Northern Europe had the highest amphetamine loads: Antwerp (221.87), Reykjavík (139.00), Amsterdam, (82.38), Oslo (77.76). Highest benzoylecgonine loads occurred in western and southern Europe: Antwerp (755.94), London (729.01), Zürich (650.03), Amsterdam (629.96), Barcelona (561.31). MDMA loads were highest in the Netherlands: Amsterdam (135.55). Methamphetamine loads were highest outside of Europe in Australia: Adelaide (576.54), the United States: Seattle (418.49), and Canada: Granby (407.67). The highest THC-COOH loads emerged in Amsterdam (282.48) and Barcelona (194.20). Benzoylecgonine loads increased across Europe, amphetamine and methamphetamine loads fluctuated, MDMA loads exhibited an intermittent upsurge, while THC-COOH loads exhibited stable use. Overall, WBE results corresponded to contemporaneous prevalence/seizure data. With objective, near real-time drug use estimates and superior detection of new drug use trends (compared with traditional epidemiological indicators), WBE augments conventional prevalence/seizure data and improves understanding of international illicit drug use.