Monitoring of Pharmaceutical and Personal Care Products in the Upper Reaches of the Yamato River System

We investigated concentrations of 18 pharmaceutical and personal care products (PPCPs) in the upper reaches of the Yamato river system using LC-MS/MS in winter and summer in 2020. This river system extends over the Yamato plain area which accounts for nearly 90% of the population in Nara prefecture, and the river flow rate is extremely lower than others in Japan. Therefore, high concentrations of PPCPs from the residential and commercial sector are expected to be detected. As a result, 17 PPCPs were detected in one of the rivers. The results were compared with those of a previous study in a large urban area, and showed that differences in drug use due to the aging of the population and differences in sewerage coverage may affect differences in the frequency of PPCPs detection in rivers. Furthermore, by comparing the concentration ratios of PPCPs, it was possible to identify points where the concentration ratios of PPCPs were different from those of other water sampling points, reconfirming the importance of regional surveys. We compared PPCPs concentration with predicted no-effect concentration (PNEC) to assess the ecological impact. As a result, clarithromycin, erythromycin, diclofenac, and carbamazepine which were detected in excess of the PNEC. The concentrations of these substances were similar to or lower than those in previous studies.