Illicit drugs in wastewater treatment plants utilization of wastewater-based epidemiology in a Brazilian regional city

Illicit drugs, belonging to a category of contaminants of growing and threatening concern, must be taken into account in environmental management due to their social and public health risks. Wastewater-based epidemiology consists in acquiring relevant information about the lifestyle and health status of the population through the analysis of wastewater samples collected at the influent of a wastewater treatment plant (WWTP). This method has been applied to the analysis of influent samples from 4 WWTPs located in Rio de Janeiro Municipality, Brazil, in order to investigate the presence of illicit drugs and their metabolites. These included cocaine (COC), benzoylecgonine (BE, cocaine metabolite), amphetamine (AMP), methamphetamine (METH), and 11-nor-9-carboxy-tetrahydrocannabinol (THC-COOH, THC metabolite). Concentrations of COC and its main metabolite BE ranged from 201.3 to 2751.5 ng/L and from 630.7 to 5849.2 ng/L, respectively. Amphetamine-like stimulants ranged from 1.7 to 110.0 ng/L for AMP, and from 55.3 ng/L to 477.4 ng/L for METH. THC-COOH ranged from 188.8 to 940.2 ng/L. The concentrations found, besides being significant to public health, can potentially influence the functioning of the ecosystem. It is important to detach that COC and amphetamines (including metabolites as well) have potent pharmacological activities and their presence as complex mixtures in the environment may cause an adverse effect on aquatic organisms and in human health. However, unfortunately, there is no current regulation demanding the determination of the occurrence of these pollutants at the environment. This way, researches on the distribution pattern of these illicit drugs and their potentially harmful impact on our environment needs immediate attention and regulatory limits.