Microplastics in Pacific Northwest Bivalves: Ecological Prevalence, Harvester-Consumer Exposure, and Aquarium Exhibit Outcomes

• Main Author: Baechler, Britta Rahel
• Other Authors: Oregon State University. Sea Grant College Program
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Portland State University
• Subjects: Pacific; Crassostrea gigas
• Online Access: https://ir.library.oregonstate.edu/concern/defaults/ns064d627

Up to 23 million metric tons of mismanaged plastics enter the global ocean annually. Microplastics (MPs;<5mm) degrading. MPs leak into the environment and now pervade every corner of the earth, with implications for animal, plant, ecosystem and human health. It is important to understand localized environmental MP prevalence, distribution and organismal uptake in order to determine the extent of MP pollution, and ultimately unlock solution sets to reduce transmission of MPs into the natural world. In Chapter 2, I quantified MP types, concentrations, anatomical burdens, geographic distribution, and temporal differences in Pacific oysters (Crassostrea gigas) and Pacific razor clams (Siliqua patula) from 15 coastal sites in Oregon. Both of these species are integral to culture, economy, gastronomy and food security along the United States West Coast. In Chapter 3, I quantified MPs in Pacific razor clams collected from 8 Olympic Coast, Washington sites, administered questionnaires to recreational razor clammers and subsequently estimated annual MP exposure of those Olympic Coast razor clam harvester-consumers surveyed. In Chapter 4, I designed and installed an educational ocean plastic exhibit at the OR Coast Aquarium. I evaluated time spent in the exhibit, number of times panels were read or interactive elements were touched, determined current and intended single-use plastic reduction and plastic stewardship actions by visitor demographic, gauged visitor learning after the exhibit experience and recorded suggestions for exhibit improvement. MPs were present in Pacific oysters and razor clams from all 23 (15 OR and 8 WA) sites studied in Chapters 2 and 3. Among all clams and oysters studied in both OR and WA, over 99% of MPs encountered were fibers. In OR bivalves, whole oysters and razor clams contained an average of 10.95 ± 0.77 and 8.84 ± 0.45 MP pieces per individual, or 0.35 ± 0.04 and 0.16 ± 0.02 MP g-1 tissue, respectively. Spring-collected oysters contained more MPs than summer-collected oysters. In WA ...