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Date Permissions Signed


Date of Award

Summer 2022

Document Type

Masters Thesis

Department or Program Affiliation

Environmental Sciences

Degree Name

Master of Science (MS)


Environmental Sciences

First Advisor

Bauman, Jenise

Second Advisor

Montaño, Manuel D.

Third Advisor

Sofield, Ruth M.


Estuaries are unique environments which provide many needed ecosystem services, but are threatened by anthropogenic activities. Contamination with metals represents a significant concern, as even small amounts can persist in the soil and affect biological functions. Phytoremediation, or the use of plants to take up contaminants from the soil, is one possible solution. There is a lack of research on estuarine phytoremediators native to the Pacific Northwest, as well as the ultimate fate of these metals following plant senescence. In this study, we evaluated the total metal concentration at three Whatcom County, WA estuaries and sampled four native plant species (Atriplex patula, Distichlis spicata, Juncus balticus, and Plantago maritima) at these sites repeatedly throughout the growing season. We used acid digestion of both plant tissue and soil, as well as a four-step sequential extraction of the soil, to measure metal concentrations with inductively coupled plasma mass spectrometry (ICP-MS). Elevated concentrations of metals were found at California and Padden Creek estuaries, while Chuckanut Village pocket estuary had metal concentrations aligned with the median background concentrations for the region. All four plant species were found to be hyperaccumulators of selenium. Atriplex patula, P. maritima, and J. balticus were found to accumulate magnesium, zinc, cadmium, and silver in appreciable quantities, with J. balticus also accumulating manganese. Metal concentrations in aboveground tissue declined over time, with the steepest decreases seen in A. patula and P. maritima. Numerous factors, such as pH and salinity, are known to affect the bioavailability of these metals in soil; sitespecific measurements supported these influences. When choosing plants for phytoremediation, land managers should take care to consider the overall needs of their site and additional ecosystem services that vegetation can provide in conjunction with bioaccumulation abilities.




estuaries, phytoremediation, bioaccumulation, metals


Western Washington University

OCLC Number


Subject – LCSH

Estuarine ecology--Washington (State)--Whatcom County; Metals--Bioaccumulation--Washington (State)--Whatcom County; Phytoremediation--Washington (State)--Whatcom County; Soil pollution--Washington (State)--Whatcom County

Geographic Coverage

Whatcom County (Wash.)




masters theses




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