Monitoring pharmaceuticals consumption using PERK: a study utilizing prescription data collected at the river catchment level with high spatial resolution

The prescription data of selected pharmaceuticals were utilized to predict their concentrations in the wastewater influent. A combined wastewater-based epidemiology and environmental risk analysis protocol was developed. Prescription data for the catchment area is derived from England’s National Health Services monthly prescription database using PrAna 1. Using PERK 2, predicted environmental concentration (PEC) of pharmaceuticals were estimated and validated against measured environmental concentration (MEC). The wastewater monitoring data obtained from five different wastewater treatment plants in the Southwest of England (WWTP A to E) were used 3. The model can predict accurate results for 16 pharmaceuticals (0.5 < PEC/MEC < 2) and acceptable results for 31 out of 36 pharmaceuticals (0.1 < PEC/MEC < 10), according to comparisons between predicted environmental concentrations (PEC) of pharmaceuticals in wastewater influent (PECinfluent) and measured environmental concentrations (MECinfluent) reported in prior study. 28 of the pharmaceuticals that were studied were prescription-only medicines (POM). The model achieved accurate results for 12 pharmaceuticals and acceptably accurate results for 24 out of 28 pharmaceuticals in POM, where prescription counts are presumed to be a good indicator of use. For most of the pharmaceuticals under study at the five WWTP locations, there were similar variation between measurements and prescriptions.

Pharmaceutical removal percentage (Removal%) was calculated using measured effluent and influent concentrations. The Removal% and PECinfluent were used to predict the PEC values in effluent (PECeffluent). Metformin, tramadol, naproxen, and carbamazepine were the top five medicines found in wastewater at all five study sites, with values from 0.3 to >25 g/L. Due to both their high consumption and low removal rates in WWTP, the top five pharmaceuticals had PECeffluent levels that were high (>4 g/L) in the wastewater effluent at WWTP D. As part of the environmental risk assessment (ERA), the PEC to predicted no effect concentrations (PNEC) ratio for several pharmaceuticals was also computed.

References
1. K. K. Jagadeesan, J. Grant, S. Griffin, R. Barden and B. Kasprzyk-Hordern, BMC Medical Informatics and Decision Making, 2022, 22, 5.
2. K. Jagadeesan, R. Barden and B. Kasprzyk-Hordern, Environmental Modelling and Software, 2022, In review.
3. K. Proctor, B. Petrie, R. Barden, T. Arnot and B. Kasprzyk-Hordern, Anal Bioanal Chem, 2019, 411, 7061-7086.