Levels of ⁶⁵Zn in water, sediments, plants, and animals in
Alder Slough, a small ecosystem in the Columbia River Estuary,
were determined periodically during a one year period. Concentrations
of total Zn in organisms were also measured to permit
computation of specific activities (μCi⁶⁵Zn/g total Zn). Temporal
fluctuations in the activities of ⁶⁵Zn and the concentrations of total
Zn occurred in all components of the ecosystem.
Activities of ⁶⁵Zn and concentrations of total Zn varied among
individual fish from the study area. Pooled estimates of population
standard deviations of these values in all samples of two fish species
taken during the year amounted to about 20% of their grand means.
Usually, individuals with high ⁶⁵Zn activities also proved to have
high total Zn concentrations, hence specific activities were less
variable than either ⁶⁵Zn or total Zn.
The nuclear reactors at Hanford, Washington, the source of
most of the ⁶⁵Zn in the Columbia River, were shut down for approximately
45 days during this study. This event presented the opportunity
to investigate the response of various components of the ecosystem
to reduced ⁶⁵Zn input. The rates of ⁶⁵Zn specific activity
decline in several organisms were measured following reactor shutdown.
The time required for specific activity of an organism to be
reduced by one-half under the conditions prevailing is termed "ecological
half-life". The "ecological half-life" differs from the biological
half-life of an organism because:
1. it is defined in terms of specific activity
2. it reflects the continued addition of radioactivity to the organism
from its food web and water.
"Ecological half-lives" vary with the trophic levels of the organisms
and with changes in prevailing ecological conditions. / Graduation date: 1968
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/28399 |
| Date | 22 August 1967 |
| Creators | Renfro, William Charles |
| Contributors | Osterberg, Charles L., Forster, William O. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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