2018 Volume 16 Issue 3 Pages 149-160
Water sampling was conducted in the coastal area of Tokyo following two rainfall events in October and November 2016. The coastal area receives, through urban rivers, a considerable amount of combined sewer overflow (CSO) pollutants from overflow chambers and pumping stations. Five pharmaceutical and personal care products (PPCPs) including acetaminophen, theophylline, crotamiton, carbamazepine, and caffeine were analyzed and used as chemical sewage markers. In addition, two types of bacteriophage were counted as markers for viral contamination as well as the fecal bacterial indicators Escherichia coli and total coliform. High contamination by PPCPs and microbial fecal indicators was observed after the rainfall events. Five key markers were selected among nine target markers using correlation analysis and were used to express the spatial distribution and temporal change in CSO pollutants. Escherichia coli showed relatively fast die-off behavior and decreased sharply from one day after the rainfall events, while bacteriophages persisted for several days after the events. Somatic coliphage showed more persistent behavior than F-specific bacteriophage. Labile markers such as caffeine also showed high rates of disappearance. In addition, monitoring results suggested that combined analyses of PPCPs and microbial fecal indicators can provide a more informed discussion on the distribution and diffusion of sewage contaminants in coastal waters following rainfall events.