Antivirals in Wastewaters and Receiving Waters: Analytical Methods and Occurrence Data

The presence of pharmaceuticals in environmental waters has been studied for almost two decades after developments in analytical instrumentation and sample preparation enabled their detection by lowering detection limits. The COVID-19 pandemic shifted the attention toward antivirals. Analytical methods for measuring antivirals in blood and serum samples are abundant, but these methods cannot be directly used for water and wastewater samples. A literature survey conducted for studies published in the last 5 years indicates that a combination of SPE with liquid chromatography coupled with different types of mass spectrometers can detect concentrations as low as 0.04 ng/L in surface waters. Wastewater presents a slightly more complex matrix leading to slightly higher Limit of Detection/Limit of Quantifications (LOD/LOQ)’s. The use of antivirals is more specific for the geographic area than most of the other micropollutants, hence the occurrence data also are area-specific. Anti-influenza drugs have been studied mostly in Japan, whereas most of the research on antiretrovirals has been conducted in Africa. The concentrations depend on the type of antiviral and the aqueous media where they are measured. As expected, the highest concentrations are detected in raw wastewater samples (0.8 mg/L for abacavir), emphasizing the importance of wastewater treatment to prevent the discharge of antivirals into the environment. Removal efficiencies vary widely with some effluents having higher concentrations than the influent. In some locations, antiviral concentrations of surface water may be as high as those in wastewater samples. Therefore, due to the presence of antivirals together with other pharmaceuticals or other micropollutants, it is essential that the occurrence data are supported by toxicity studies to understand their importance in the environment.