Hall, Keely2021-09-282021-09-282021http://hdl.handle.net/1773/47763Plastic material is the most prominent constituent of pollution in the marine environment and it has a myriad of adverse consequences. This research investigates the contribution of microplastics to Puget Sound, Washington, via the Puyallup River from 2017 to 2018. Datasets from UW Tacoma were analyzed to determine spatial and temporal variation of microplastic abundance across nine sampling stations. The stations were located around the Puyallup River’s nearby wastewater treatment plants (WWTPs) as these plants act as possible sources of pollution. A majority of the data indicated that microplastic abundance increased from 2017 to 2018 (P = 0.0287). Additionally, the data demonstrated a positive correlation between average microplastic abundance per city and total population both years (2017 R2 = 0.8749, 2018 R2 = 0.6195). Although spatial results were variable, abundance increased in the Puyallup River between the two sites closest to Puget Sound. 2018 data had a larger microplastic type distribution than 2017 with 63 percent fiber and 37 percent fragment, while 2017 only had fibers. Puyallup River results were compared to a study conducted on the Snohomish River in 2017. Mean river microplastic abundance between the two sites showed no difference in 2017 (P = 0.0549) and a significant difference in 2018 (P = 0.0008). Regulations on anthropogenic related pollution are necessary as microplastics continue to accumulate in the ocean. Further research with larger datasets and over longer timescales is crucial for resolving variability in the data and determining the impact plastic pollution has on marine communities.microplasticsPuget SoundPuyallup River