In-sample stability of selected pharmaceuticals and illicit drugs in wastewater

Xialu Lin is a PhD candidate in Health Science Center, Xi'an Jiaotong University, and presently a visiting student at QAEHS.

The stability of compounds in wastewater after sampling is an important aspect in wastewater-based epidemiology for back-calculation of substance consumption. In this study, it was assessed the stability of selected pharmaceuticals, illicit drugs and their metabolites in wastewater samples archived under different preservatives. The spiked wastewater samples were stored at four different temperatures and measured for up to 28 weeks. The pseudo first order decay or association kinetic model was used to explore the degradation or transformation trend. The influences of temperature, preservatives and physical properties on the stability were also evaluated. Finally, the estimated stable duration and proper storage condition for target compounds were summarized