Development of an analytical method for wastewater based epidemiology on pharmaceuticals

Abstract

The monitoring of pharmaceuticals in influent wastewater samples (IWW) is not only valuable from the environmental point of view, but also as a tool to analyze patterns of consumption in the region of the catchment area by the so-called wastewater-based epidemiology (WBE) approach [1,2]. In Spain, some studies [1,3] demonstrated the occurrence of pharmaceuticals in different separate IWW samples. However, there are no studies that monitored different wastewater treatment plants (WWTPs) geographically distributed to obtain a general picture on the pharmaceutical occurrence in this country. This study developed an analytical method based on solid-phase extraction using Oasis HLB followed by liquid chromatography with tandem mass spectrometry to monitor the occurrence of a group of pharmaceuticals including the most representative for therapeutic families in IWW samples. The samples were collected during a week campaign in six different WWTPs located in different cities and towns in Spain. The developed method provided successful figures of merit with recoveries in IWW ranging from 42% to 139%, and low matrix effect (in general lower than ± 30%), and method quantification limits (MQL) between 1 ng/L and 24 ng/L for all compounds, except atenolol (58 ng/L). All the studied pharmaceuticals were found in all analyzed samples with concentrations ranging from <MQL to 10,393 ng/L, being the highest concentration found for tramadol. In addition, the population normalized daily load (PNDL) data reveals that the consumption of pharmaceuticals has, in general, similar patterns in all monitored WWTPs. In summary, the proposed method is a suitable analytical tool for WBE to estimate pharmaceutical consumption.