This project implemented contaminants screening process of drinking water quality regulation. Six unregulated short-chain perfluoroalkyl substance (PFAS) were selected for evaluation. Their concentration was monitored in six representative drinking water treatment plants, and their health risk in drinking water system in Taiwan were evaluated. Results indicated that there is no significant risk of these 6 compounds on drinking water in Taiwan. This project also collected the monitoring histories of unregulated contaminants in Contaminant Candidate List (CCL). Results of dibutyl phthalate showed that there was no significant hazard in Taiwan's drinking water. Therefore, dibutyl phthalate was moved from CCL to Preliminary Contaminant Candidate List (PCCL) for effectively using examnation resource. Analysis of the boron in drinking water shows that the higher boron concentration in the clean water of the outlying island drinking water treatment plant may be related to seawater desalination. It is recommended to clarify and confirm the correlationship. In addition, this project inspected 27 unregulated compounds of emerging concern in drinking water and got 3349 data in total. There were only few samples with higher concentration on germanium, thallium, boron, Geosmin, 2MIB, PFOS, PFHxS, and NDMA. It is suggested to monitor them continuously. Besides, this project evaluated 6 different microbial indicators at 20 sampling points in water distribution system. The analysis results show that the total bacterial colony count is <20 CFU/mL, which is lower than the regulatory standard (100 CFU/mL). The results of other biological parameters are all <1 CFU/100 mL (most of international standards). Results indicated that maintain free residual chlorine is important stretagy to reduce microorganism in water distribution system. This project also compiles the detection of emerging pollutants in different water sources in the past ten years, and makes recommendations on the pollutants that my country should pay attention to in various water sources.

Per/Poly fluoro alkyl substances (PFAS), Dibutyl phthalate (DBP), boron (B)