Triangulating wastewater and a prospective survey of drug consumption – new insights for policy makers

Wastewater analysis (WWA) has rapidly cemented itself as an important tool to capture trends in drug markets. Yet while WWA measures the overall amount of drug used, it omits the circumstances in which drugs were used; information that is critical to inform policy. We outline a pilot study that triangulated WWA against a prospective drug consumption survey. 24 hour composite samples of WWA were collected over a 90-day period: 1 April to 30 June 2021 in one regional town in South Australia. An anonymous and encrypted self-report survey was administered simultaneously to a cohort of residents who use illicit drugs. Key variables included the daily incidence of drug consumption, type of substance(s) consumed, quantity used and access to services. Triangulation showed high congruence about the top four substances consumed (alcohol, tobacco, cannabis, methamphetamine). The survey data permitted novel insights into the incidence of occasional vs dependent use, demographic profiles and risk practices eg drug driving associated with each substance and ease of access to drug treatment. Triangulation brings multiple benefits for policy makers: the ability to validate findings; to differentiate trends in harm vs use; and to identify the worth of different policy responses.