Wastewater analysis has emerged as a critical tool for assessing community drug use. This study focuses on the detection of new psychoactive substances (NPS), cocaine, and cannabis in two wastewater treatment plants (WWTPs) in South Wales. The investigation provides insights into the prevalence of these substances and assesses the efficiency of wastewater treatment processes in removing them.

Study Methodology

The study involved monitoring two WWTPs—WWTP-1 and WWTP-2—over a month in 2020. Both plants serve different population sizes, with WWTP-1 covering approximately 930,624 individuals and WWTP-2 servicing around 301,443 residents. Wastewater samples were collected from Friday to Monday over four weekends, capturing peak times for drug consumption. The analysis focused on 35 NPS and their metabolites, as well as illicit substances such as benzoylecgonine (a cocaine metabolite) and cannabis.

Key Findings

• Cocaine Usage: Benzoylecgonine, the main cocaine metabolite, was the predominant substance detected at both WWTPs. Epidemiological calculations indicated an average cocaine consumption of 3.88 mg/day per 1000 inhabitants at WWTP-1 and 1.97 mg/day per 1000 inhabitants at WWTP-2.
• Wastewater Treatment Efficiency: The removal efficiency for benzoylecgonine averaged 73% across both WWTPs, demonstrating significant but incomplete removal of this compound during treatment.
• Absence of NPS: The study found no evidence of NPS in the wastewater samples, suggesting either minimal consumption within the population or challenges in detecting these dynamic compounds.
• Presence of Medicinal Compounds: Qualitative analyses revealed the presence of substances like buprenorphine, methadone, and codeine, indicating the presence of medicinal drug use within the community.

Implications for Public Health and Environmental Concerns

The findings emphasise the need for enhanced monitoring and treatment strategies to address the ongoing presence of illicit substances and medicinal compounds in wastewater systems. The absence of NPS highlights potential gaps in detection techniques or a lack of significant use within the area. This study underlines the importance of wastewater analysis as a non-invasive method to gauge community drug use, thereby informing public health policies and environmental protection measures.

Source: Nature