Microcosm Study of the Accumulation of Benzo(a)pyrene by Lake Whatcom Phytoplankton

Date of Award


Document Type


Degree Name

Master of Science (MS)


Environmental Science

First Advisor

Matthews, Robin A., 1952-

Second Advisor

Cancilla, Devon A. (Devon Anthony)

Third Advisor

Peele, Emily R.


I developed a preliminary method for measuring in situ benzo(a)pyrene (BaP) accumulation by phytoplankton using laboratory studies and natural assemblages of Lake Whatcom (Bellingham, WA) phytoplankton. Most phytoplankton BaP accumulation studies use laboratory manipulations of algal cultures, which are often monocultures rather than natural communities. Such research, while it illustrates general trends and observations, does not provide practical methodology for using phytoplanktonic bioindicators at specific sites. I intended this thesis to bridge the gap between laboratory-based studies and in situ biomonitoring.

Developed using a sequence of smaller experiments, the method attempted to balance both efficiency and high analyte recovery in measuring BaP accumulation and in characterizing the phytoplankton community under investigation. Natural phytoplankton cultures were concentrated using a Schindler trap and were exposed to BaP under laboratory conditions. Phytoplankton were characterized using three different parameters - chlorophyll a, abundance, and biovolume. The distribution of BaP was evaluated throughout the phytoplankton microcosms. Approximately 53% of the BaP was recovered from the microcosms, with the diatom-dominated phytoplankton communities showing a strong tendency to accumulate BaP.

The method successfully recovered measurable quantities of BaP from natural phytoplankton communities and met preliminary method validation criteria. Following investigation of more effective phytoplankton concentration techniques, this method could be applied to sites with prior exposure to BaP. Given the overall shortage in research regarding in situ measurement of other hydrophobic organic chemicals in aquatic bioindicators, the method could also be adapted for use with chemicals other than BaP.




Lake Whatcom phytoplankton, Benzo(a)pyrene accumulation, in situ measurement


Western Washington University

OCLC Number


Geographic Coverage

Whatcom, Lake (Wash.)




masters theses




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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