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Date Permissions Signed

2-17-2017

Date of Award

Winter 2017

Document Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Environmental Sciences

First Advisor

Bodensteiner, Leo R.,1957-

Second Advisor

Sofield, Ruth M.

Third Advisor

Rawhouser, Ashley K.

Abstract

Hard rock and placer mining have been occurring throughout the mountains in the northern portion of Washington State since the late-1800s. As a result, aquatic ecosystems in this region are susceptible to the physical, chemical and biological changes that result from mining activities. These alterations, which include changes in water chemistry, habitat modifications, and reduction or contamination of food sources, can adversely impact aquatic communities of periphyton, benthic macroinvertebrates and fish. To evaluate changes in water chemistry and biological communities in two regions with extensive mining histories, the Ruby Creek watershed and Upper Skagit River watershed, I analyzed metals in grab samples of surface water, on Stabilized Liquid Membrane Devices (SLMDs) which passively sample metals in surface waters over time, and in periphyton.

Metals were present in the water and benthos, and site-specific and temporal differences in the kinds and quantities of metals were linked to locations of hard rock and placer mining activities. Metal concentrations in surface waters differed between sites upstream and downstream of mining depending on different times when mining was or was not occurring. Metal concentrations in surface waters at some sites in the Ruby Creek watershed were high enough to be capable of adversely affecting aquatic organisms over time. Metals that were present in streams were not always detected in grab samples, but their presence was confirmed by SLMDs and periphyton. Clustering analyses of both SLMDs and periphyton each distinguished two different groups of samples, samples collected downstream of placer mining (SLMDs) and samples collected downstream of hard rock mining (periphyton). The accumulation of metals in periphyton indicated these communities could be a concentrated source of toxic metals to primary consumers, such as small aquatic insects, and may pass to other aquatic organisms at higher trophic levels through dietary exposures.

Type

Text

Publisher

Western Washington University

OCLC Number

973736591

Digital Format

application/pdf

Geographic Coverage

Washington (State)

Genre/Form

Academic theses

Language

English

Rights

Copying of this thesis in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

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