An exploratory wastewater analysis study of drug use in Auckland, New Zealand.

INTRODUCTION AND AIMS: New Zealand is considered to have unusual drug use patterns by international standards. However, this understanding has largely been obtained from social surveys where respondents self-report use. The aim of this paper is to conduct the first wastewater study of drug use in Auckland.

DESIGN AND METHODS: Wastewater sampling was completed from 2 May to 18 July 2014 at 2 Auckland wastewater treatment plants which service 1.3 million people. Samples were analysed for 17 drug residues by using liquid chromatography-tandem mass spectrometry. Consumption of methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA), cocaine, codeine and methadone (mg/day/1000 people) was estimated by using a back-calculation formula.

RESULTS: Methamphetamine, codeine, morphine and methadone were detected with high frequency (80-100%), followed by amphetamine (~60%), MDMA (~7%, i.e. 8 occasions) and methylone (3 occasions). An overall mean of 360 mg of methamphetamine and 60 mg of MDMA was estimated to have been consumed per day per 1000 people. Methamphetamine consumption was found at similar levels in both catchments (377 and 351 mg/day/1000 people). Cocaine was only detected in 1 catchment and on only 8 occasions. JWH-018 was detected in 1 catchment and only on 1 occasion. Methamphetamine, codeine and other opioids were detected at a consistent level throughout the week. 3,4-Methylenedioxymethamphetamine and methylone were detected only during the weekends.

CONCLUSIONS: Wastewater analysis confirms that methamphetamine was one of the most commonly detected illegal drugs in Auckland and was detected consistently throughout the week. In contrast, cocaine and MDMA were rarely detected, with detection limited to weekends. [Lai FY, Wilkins C, Thai P, Mueller JF. An exploratory wastewater analysis study of drug use in Auckland, New Zealand. Drug Alcohol Rev 2017;00:000-000].