Study data published in Water Research provide a comprehensive profile of new psychoactive substance (NPS) use in countries around the world. Using influent wastewater collected in 8 countries, investigators identified several novel substances with high wastewater loads, suggesting substantial community ingestion during the study period.

The morbidity and mortality risk associated with NPS necessitates their continued surveillance. However, NPS use patterns are difficult to estimate using medical records data or samples seized by law enforcement. To obtain a broader picture of NPS use, investigators collected wastewater from 14 sites in 8 countries: Australia (n=4 sites), New Zealand (n=4), China (n=1), Spain (n=1), Italy (n=1), the Netherlands (n=1), Norway (n=1) and the United States (n=1). Samples were obtained between December 25, 2019 and January 2, 2020 to capture NPS use over the New Year’s holiday.

Wastewater samples were collected according to a standardized protocol and shipped to Australia for final analysis. Liquid-chromatography-mass spectrometry (LC-MS) was used to assess samples for the presence of NPS of interest. Two study approaches were employed: qualitative identification of NPS compounds and quantification of NPS levels. In qualitative analyses, compounds were identified based on retention time and the presence of certain mass ions. NPS levels were quantified based on sample concentration, daily wastewater flow, and population at collection sites. Identified substances were tabulated by date and site of identification.

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A total of 10 NPS were quantified in wastewater analyses: 3-methylmethcathinone (3-MMC), 4-fluoroamphetamine (4-FA), 4-methylethcathinone (4-MEC), ethylone, methylenedioxypy-rovalerone (MDPV), mephedrone, methcathinone, methylone, N-ethylpentylone and pentylone.

Of the 8 studied countries, 7 had NPS at semi-quantifiable levels: the Netherlands (n=6 distinct NPS); New Zealand (n=4); Australia (n=4); the United States (n=3); Spain (n=2); Italy (n=2); and China (n=1). Only samples from Norway did not display quantifiable levels of any NPS of interest. The most prevalent NPS was methcathinone, identified at 13 study sites. The next most prevalent NPS was N-ethylpentylone, found at 8 sites across Australia, New Zealand, and the United States. 3-MMC was found in Spain, Italy, and the Netherlands, and displayed increasing use trends between December and January. Methylone was found in the Netherlands and New Zealand; pentylone was observed only in the United States.

Per qualitative analyses, ketamine and its metabolite norketamine were observed at each study site. Eutylone was observed in Australia, New Zealand, the Netherlands, and the United States. Mitragynine was observed in the United States only, on all days during the study period. 4-Chloromethcathinone was identified in Italy only; 4-fluoromethamphetamine was present in the Netherlands alone.

Results from these wastewater analyses provide insight into psychoactive substance use in 8 countries around the world. Geographic differences were observed, suggesting that interventions to reduce drug-related morbidity and mortality may benefit from localized efforts.

As study limitations, investigators emphasized that no more than 4 wastewater sites were studied in each country. Results are thus not generalizable on a national scale. Further, certain psychoactive substances — including benzodiazepines and cannabinoids — are not quantifiable in wastewater analyses.

“This case study is the most comprehensive wastewater analysis study ever carried out for the identification of NPS and provides a starting point for future, ongoing monitoring of these substances,” the investigators wrote. “Despite the number of ‘new’ NPS reportedly declining in recent years, this work shows that they are still used within communities and across countries, [emphasizing] the need for continued surveillance and monitoring.”


Bade R, White JM, Chen J, et al. International snapshot of new psychoactive substance use: Case study of eight countries over the 2019/2020 new year period. Water Res. Published online February 3, 2021. doi: 10.1016/j.watres.2021.116891