Biology ETDs

Publication Date

5-2-1973

Abstract

Flameless atomic absorption analysis of samples from Lake Powell yielded mercury in mean parts per billion of 0.01 in lake water, 30 in bottom sediments, 10 in shoreline substrate, 34 in plant leaves, 145 in plant debris, 28 in algae, 10 in crayfish, and 232 in fish muscle. Concentrations are expressed on a wet-weight basis for animals, all other samples are on a dry-weight basis. In bottom sediments mercury levels were higher in sediments with higher organic content and finer texture. The mercury content of plant leaves was higher than that of stems and roots. Lake­transported plant debris had higher mercury levels than did shoreline plants. In rainbow and brown trout bloody tissues had higher mercury levels than did muscle or other tissues. In the six other species of fish analyzed mean relative mercury levels compared to muscle as 1.00 were: liver 0.51, heart 0.43, kidney 0.36, spleen 0.28, stomach 0.20, brain 0.16, gonads 0.14, skin 0.13, gills 0.12, and bone 0.07. Larger fish of a species and fish of higher trophic levels had higher mercury concentrations, with the muscle of large walleye and largemouth bass exceeding 500 ppb. Biomagnification and the association of mercury with organic matter are evident in this recent, relatively unpolluted reservoir. Formulation of an estimated mercury budget suggests that the restriction of outflow in the impounded Colorado River leads to mercury accumulation, and that projected regional coal-fired power generation may produce sufficient mercury to significantly augment the mercury released by natural weathering. The extent of this augmentation and its effect on Lake Powell depends principally upon the actual mercury content of the coal, the degree to which this mercury enters the lake drainage, and its movement and bioamplification within the system.

Project Sponsors

Grants NSF-GI-29422 and NSF-GI-34831 as a part of the National Science Foundation funded Lake Powell Research Project

Language

English

Document Type

Thesis

Degree Name

Biology

Level of Degree

Masters

Department Name

UNM Biology Department

First Committee Member (Chair)

Loren David Potter

Second Committee Member

James Roman Gosz

Third Committee Member

David Eugene Kidd

Fourth Committee Member

Gordon Verle Johnson

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