Abstract
In recent years, pharmaceuticals and their metabolites have been detected in aquatic environments, and their risk management has become an emergent concern about the environment, water supply and sewerage. In particular, pharmaceuticals for external use may be discharged in large amounts into aquatic environments. In this study, we monitored three pharmaceuticals for external use, namely, crotamiton, lidocaine and diethyltoluamide (DEET), in water samples (i.e., river water, effluent of wastewater treatment plants (WWTPs), and groundwater) from the Tama river basin in Japan. The calculated loads of the target compounds in effluent samples from WWTPs in the Tama river basin were comparable to those in the river water samples, indicating that the major source of the compounds is wastewater effluent. The loads in the WWTP effluent samples varied seasonally depending on their application. The removal efficiency of groundwater recharge varied among the target compounds. Lidocaine and DEET were removed more efficiently than crotamiton. The removal efficiency of chlorination also varied among the target compounds. Although negligible amounts of crotamiton and DEET were removed, lidocaine was almost completely removed within 1 hour.
