A hospital within the catchment area of Bath was also investigated to compare differences in composition between community influent and hospital effluent. Concentrations of certain AAs were found to be elevated in hospital effluent in comparison with community derived wastewater, including for SMX, TMP, and MTZ. It was also noted that there was a higher percentage of macrolides in hospital effluent than in community influent (42% versus 11%). Compositions in wastewater were compared to hospital prescribing, with notable differences in what was prescribed with what was reflected in wastewater. For example, penicillins were 33% of all AAs prescribed in hospitals during the sampling moth but only 6% was observed in hospital effluent. These differences in composition of prescription data and for wastewater results, are mainly attributed to human metabolism and possible transformation in wastewater environments. Beta-lactam AAs, like penicillins, have high susceptibility to hydrolysis due to the constrained four-member ring and usually rapidly degrade in the environment .