Regarding high abundance in wastewater, SPY was observed in high levels in both Bath and Keynsham respectively (43.1 ± 16.4 g/day and 5.6 ± 3.1 g/day). This corresponded with high levels of aSPY, with 32.0 ± 13.0 and 1.4 ± 1.13 g/day in the two sites respectively. As previously mentioned, SPY is no longer prescribed for human use in the UK, but is continued to be used as a veterinary medication. Both SPY and aSPY however are major metabolites of SLZ, which is prescribed for humans as an antiinflammatory. In wastewater, SLZ had lower average loads than its respective metabolites, at 7.41 ± 5.10 and 0.94 ± 0.63 g/day in Bath and Keynsham, previous work has demonstrated SLZ has lower recovery and stability comparatively to its two metabolites . It is likely that SPY and aSPY residues will be present in influent from a combination of consumption of SLZ on the community level and other sources, including agricultural run-off of SPY into the sewage system.