Pharmaceutical biomarkers to inform public and environmental health law and policy

Abstract

The increasing awareness of the prevalence of prescription and illicit drug metabolites in wastewater is affecting changes to public and environmental health laws and policies. Drug takeback laws have been enacted to limit environmental pollution from drugs flushed into sewers; however, these laws only apply to legally prescribed drugs. Wastewater-based epidemiology, which relies on the measurement of drug concentrations in untreated wastewater, is also emerging as a complementary drug-use data tool to estimate drug consumption patterns by a community in near real-time. We sampled both the untreated influent and treated effluent at two locations in Montana over three months from April to June, 2019, to ascertain the concentrations of certain prescription and illicit drugs of abuse. The concentrations of drugs obtained from the untreated influent were used to inform a wastewater-based epidemiology study that compared drug-dose estimates from our wastewater samples against existing local drug-use sources (emergency medical services calls, drug seizures, and prescription dispense data). We also measured the treated effluent to determine the concentration at which drugs of abuse are persisting through the wastewater-treatment process and potentially affecting aquatic life exposed to those concentrations in receiving waters. We undertook a risk assessment whereby measured drug concentrations were assessed against corresponding ecotoxicology thresholds. Our results indicate that both codeine and morphine concentrations were above predicted no-effect concentrations. The overall results indicate that (1) wastewater-based epidemiology may be an effective tool to better describe substance abuse in communities and (2) drugs are persisting at levels above ecotoxicological thresholds from wastewater treatment plants into receiving waters. To our knowledge, these investigations are the first of their kind to have been conducted in Montana.