Puget Sound Microplastics

learning journey
Author

Sarah Tanja

Published

April 15, 2024

Modified

September 1, 2025

if ('tidyverse' %in% rownames(installed.packages()) == 'FALSE') install.packages('tidyverse')
library(tidyverse)
Learning Objective

What are the commonly measured concentrations of microplastics in Puget Sound, Washington? This goal of this objective is to understand the environmentally relevant range of this type of pollutant.

“Simply stated, we do not currently know levels of microplastics in the ocean (water, sediments, organisms), the spatial and temporal distribution of microplastics, the sources of these materials (either in absolute or relative terms), or the direct or indirect impacts microplastics may be having on marine life. From a basic understanding of the processes degrading plastic in the environment, it is likely that marine microplastics will persist in the ocean for very long times, and that levels of microplastics are likely accumulating world-wide (Thompson et al., 2004).” - Center for Urban Waters, Sources and Distribution of Marine Microplastics

1 Who monitors marine microplastics in Puget Sound and the Salish Sea, and what are they finding?

1.0.1 Seattle Aquarium

Seattle Aquarium, Seattle, Washington engages in long-term monitoring of plastics and marine debris collected from their seawater intake pump and off the side of the pier where they are located. They published some of their data taken from 2019-2020 in Harris et al. (2022), where they indicate they found between 0.0 and 0.64 microparticles sized between 330 μm to 5000 μm per liter of seawater sampled.

Only microparticles 330 to 5000 μm (length; Masura et al., 2015) were categorized and measured due to the resolution of the microscope and camera. - Harris et al. (2022), p. 919

Harris, Lyda S. T., Laura La Beur, Amy Y. Olsen, Angela Smith, Lindsey Eggers, Emily Pedersen, Jennifer Van Brocklin, Susanne M. Brander, and Shawn Larson. 2022. “Temporal Variability of Microparticles Under the Seattle Aquarium, Washington State: Documenting the Global Covid-19 Pandemic.” Environmental Toxicology and Chemistry 41 (4): 917–30. https://doi.org/10.1002/etc.5190.
  • data from years 2019-2020

  • data from 9m depth at Seattle Aquarium intake pump in downtown Seattle

  • seawater matrix

  • size class: 330 μm to 5000 μm

1.0.2 Puget Sound Ecosystem Monitoring Program (PSEMP)

2022 Toxics Monitoring Synthesis

1.0.3 Pollution Tracker

Coast-wide Marine Pollution Monitoring Program in British Columbia, Canada

Elizabeth Ruberg, Marie Noel, Kelsey Delisle (Ocean Wise, https://pollutiontracker.org)

Pollution Tracker, Microplastics

  • Pollution Tracker Phase 1 (2015-2017) and Phase 2 (2018-2020) provide a high-quality coast wide baseline dataset

  • During Phases 1 (2015-2017) and 2 (2018-2020), both legacy pollutants and emerging contaminants of concern were measured in sediment and mussels

  • Microplastics were characterized in sediment and mussels

  • Phase 1 results have been summarized in Noel et al. 2022 (under review) and will be posted once published. Key results include:

    • Microplastics averaged 32.6 ± 5.3 particles per kg in sediment and 0.38 ± 0.04 particles per individual mussel

    • Victoria Harbour and the North Coast were microplastics hotspots along the BC coast

    • Polyester and polyethylene dominated the polymer patterns in sediment and mussels

    • Analysis of Phase 2 microplastics samples and interpretation of results is in progress.

1.0.4 Frances Eshom-Arzadon, University of Washington School of Oceanography

site <- c('alki', 'carkeek', 'goldengardens', 'howarth', 'mukilteo', 'dash', 'tolmie', 'elliot', 'discovery', 'shine', 'picnic', 'edmonds')

microplastic_pieces <- c(249, 285, 135, 312, 30, 138, 111, 126, 135, 102, 114, 39)

eshomarzadon <- tibble(
  site = site, 
  microplastic_pieces = microplastic_pieces
  )

mean(microplastic_pieces)
[1] 148
sd(microplastic_pieces)
[1] 89.05259
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library(ggplot2)
library(dplyr)
library(hrbrthemes)
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      Please use hrbrthemes::import_roboto_condensed() to install Roboto Condensed and
      if Arial Narrow is not on your system, please see https://bit.ly/arialnarrow
library(viridis)
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Loading required package: viridisLite
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eshomarzadon %>% 
  ggplot(aes(x=site, y=microplastic_pieces)) +
  geom_violin(width=1.4) +
  geom_boxplot(width = 0.1, color = 'grey', alpha=0.2) +
  scale_fill_viridis(discrete=TRUE) +
  theme_ipsum()
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Warning in max(data$density): no non-missing arguments to max; returning -Inf
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  • followed NOAA Marine Debris Program lab manual methods

“As part of her senior thesis project, Eshom-Arzadon visited each location once at the same time in the tidal cycle between November and February. She scraped sediment from an area just below the wrack line, the line of debris left by the high tide. She visited beaches from Tolmie State Park near Olympia, along the Seattle and Everett shorelines and as far out as Port Ludlow on the Olympic Peninsula, a control site far from populated areas.” - Hannah Hickey, UW News

1.0.5 Jessica Moats, University of Washington School of Oceanography, Vertical distribution of microplastics in Hood Canal and Main Basin, Puget Sound, Washington

  • undergrad senior thesis
  • mentored by Kathy Newell
  • followed NOAA Marine Debris Program lab manual methods
  • 3.05x10-5 g/m3 average microplastic concentration across depths and sites
  • 1 cubic meter is 1000 liters
  • So we’re looking at 3.05X10-8 grams per liter in seawater

1.0.6 Keely Hall, University of Washington School of Oceanography

  • net tows through Commencement Bay

  • seawater matrix

  • data from UW Tacoma

  • data from years 2017 - 2018

  • 63% fibers, 37% fragment in 2018

  • 100% fibers in 2017

  • ~30-4 particles per liter in 2017

  • ~4-12 particles per liter in 2018

1.0.7 Julie Masura, UW Tacoma Teaching Professor

1.0.8 Center for Urban Waters

Puget Soundkeeper Microplastic Community Science Initiative

via EPA Microplastic Beach Sediment Protocol and Marine Debris Tracker

1.0.9 Pacific Northwest Consortium on Plastics

Oceanography senior thesis archive, microplastics search: https://digital.lib.washington.edu/researchworks/handle/1773/2306/discover