Temporal variation of microplastics occurrence in river water discharged to coastal region

There has been an increasing interest in small plastic particles known as microplastics (MPs). Although most of MPs found in marine environments are suspected to originate from the inland, most of microplastics (MPs) studies have been concentrated to marine environment such as mostly coastal region and there are relatively a few studies on MP occurrence in freshwater system. Discharge of riverine MPs to coastal region may vary depending on meteological condition. However, temporal variation in occurrence of MPs in freshwater and their discharge to coastal region has been not well characterized so far. In the present study, we have monitored MP abundance in the largest river (Han river) of Korea through a regular monthly survey (from February 2019 to January 2020). For monthly variation, we obtained three composite samples in a day of every month. Every composite sample were made up 3 to 5 water layers from surface to bottom at every three different sites ( left, center, and right side) along the transection of river to represent the average MP abundance. Additionally, we measured hourly variation of MP abundance in river waters for which subsurface river waters were collected for 24 hours every 2 hours in both a dry day (April, 2019) and a heavy rainfall event. In this conference, we expect to present the temporal variation in MP occurrence and its riverine discharge in terms of hourly, monthly, and rainfall effect.