Quantification of Microfibers from Marine Sediments from Three Locations in Southern California: An Exposed Beach (Ventura County), a Watershed (Los Angeles County), and an Enclosed Harbor (Orange County)

Microfibers are small (<5 mm) fibers made of synthetic materials that are ubiquitous in the environment. The purpose of this observational study was to quantify the number of microfibers in marine sediments and determine which locations have the highest risk for this type of pollution. Sediment samples were taken from three locations in Southern California (Sycamore Watershed, Ventura State Beach Jetty, and Newport Beach Harbor) to determine which had the highest number of microfibers. It was hypothesized that microfibers would be found at each sample site and that the most microfibers would be found at Sycamore Watershed due to its proximity to a wastewater discharge point. The microfibers were separated from the sediment through a process of stratification and filtration and analyzed by a one-way ANOVA and Tukey’s test. Per sample, there was an average of 111.5 (土99.3, n=14) microfibers found per sample at Sycamore Watershed, 59 (土17.4, n=18) at Newport Beach Harbor, and 53 (土14.4, n=18) at Ventura State Beach Jetty. A total of 3,590 microfibers were found from all three sample sites. Analysis revealed that Sycamore Watershed had significantly more microfibers than any other site (p<.05). It is likely that Sycamore Watershed had the most microfibers because of its proximity to a sewage-sludge disposal site that contains the polluted water from our washing machines. In conclusion, microfibers are polluting the sediments in harbors, open coastlines, and watersheds in California, negatively affecting the ecosystems in these areas. KEYWORDS: Microfiber; Microplastic; Macroplastic; Marine Pollution; Synthetic Materials; Wastewater Treatment Plants; Sediments; Watershed; Harbor; Jetty