Wastewater Surveillance of Pharmaceuticals and Genes: Challenges and Opportunities

Wastewater-based epidemiology (WBE) using viral nucleic acids to predict community viral outbreaks has many challenges, including interferences from the wastewater matrix. Liquid chromatography with tandem mass spectrometry (LC-MS/MS) monitoring of pharmaceutically active compounds, such as antivirals and over-the-counter drugs commonly used to relieve the symptoms of infection, could complement information provided by molecular techniques. For instance, residues of drugs associated with managing Covid-19 symptoms, including azithromycin, chloroquine, hydroxychloroquine, and lopinavir, have been detected in influent wastewater. A significant correlation can be observed between the total of Covid-19-related drugs detected and the 5-day rolling averages of reported cases. Spikes in acetaminophen concentrations can also be observed a couple of weeks before a spike in SARS-CoV-2 RNA copies in wastewater, suggesting that over-the-counter analgesic concentrations in raw sewage may be used to complement viral RNA data as an early-warning system for effective management of viral outbreaks at the community level. Sample preparation and analysis of pharmaceuticals in wastewater present unique challenges and are discussed in this article.