UC Santa Cruz

Microplastic presence and its potential adverse impacts on wildlife are not yet well understood in coastal ecosystems. Using standardized methods such as an alkaline tissue digestion and Raman spectroscopy, we quantified the presence, category (e.g. fiber or fragment), and polymer identification of microplastics (particle size < 5 mm) in three representative sample types of the coastal system: seawater (n=12 17 h trials), northern anchovies (Engraulis mordax, n=24), and common murres (Uria aalge, COMU, n=19). We assessed the recovered microplastics from COMU for xenoestrogenic activity using an in-vitro estrogen receptor activation assay. Particles were recovered from all sample types: 100% prevalence in the 17 h seawater trials, 58% prevalence in anchovies, and 100% prevalence in COMU. Fibers were the most abundant particle (77%), followed by fragments (13%), foam (5.8%), film (2.0%), and bead (0.78%). Raman spectroscopy identified 11 out of 20 particles that were microplastic (synthetic, semi-synthetic, or blends) as polyester. In addition, particles recovered from digestive tracts of three common murres had potential xenoestrogenic activity. To our knowledge, this study is the first to analyze and provide baseline information on the presence and potential hormone-disrupting activity of microplastic in the Monterey Bay (California) coastal system.