Occurrence, source apportionment and risk assessment of selected pharmaceuticals and their transformation products in the effluent-impacted rivers

The presence and risk of pharmaceutically active compounds (PhACs) in the aquatic environment have received global attentions recently, while the information about their transformation products (TPs) is limited. In this study, the occurrence and behavior of 40 common PhACs and TPs belong to 10 categories were investigated in the surface water of Ningbo city in China for two consecutive years. A total of 23 PhACs and TPs were detected among 20 sampling sites with the overall concentrations in the range of 77.7–742.8 ng/L. Source apportionment found that about 70% of the PhACs originated from the discharge of WWTP effluent. Caffeine and TPs 10,11-dihydroxycarbamazepine were typical indicators to differentiate unbiotreated and biotreated wastewater. CFI and fluoxetine were the pollutants with the highest risk value. The results indicated that the hydrodynamic conditions of rivers should also be considered to promote the biotic and abiotic transformation of PhACs besides pollution source control. [Display omitted] •More severe pollution of TPs was observed in the urban watersheds of Ningbo city.•The river confluent is the sensitive point with the highest pollution level and risk.•DiOH-CBZ and CFI could be used as indicators of source identification.•Attenuation in rivers reduced the overall concentration by about 30%.•The integrated risks of psychotropic drugs cannot be ignored.