Date of Award:

5-1977

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Plants, Soils, and Climate

Advisor/Chair:

W. F. Campbell

Abstract

A major issue facing nuclear power stations is how to effectively deal with radioactive waste. This waste, as it comes from a reactor, is emitting large quantities of ionizing radiation which is usually confined. Another form of radioactive wastes is the mill tailings from uranium processing plants. These tailings are sites characterized by low-level chronic radiation.

The mill tailings of the Vitro Chemical Plant, in Salt Lake City, Utah, have been a point of radionuclide concentration and environmental contamination for 20 years. These tailings may adversely affect both surrounding ecosystems and any biological systems seeking to become established on the site. To test the potential hazard of this site to the succession of plant species I examined the interphase chromosome volume and relative amounts of DNA per chromosome from plants growing on this site and those on a control site. These nuclear parameters indicate the relative radio-sensitivity of a species and would demonstrate the total effectiveness of the low-level chronic radiation in altering plant succession. The radiosensitive plant Tradescantia clone 02 was also grown in five soil samples from the mill tailings which represented a progressive increase in radioactivity. The purpose was to determine how effective these radiation levels are in altering reproductive integrity, fecundity, and somatic mutation rates in radiosensitive plant species.

There was a difference in species composition between plant communities growing on the mill tailings as compared to the controls as determined by coefficient of community. However, there was no difference in interphase chromosome volume or relative amounts of DNA per chromosome between plants growing on these two sites. The difference in species composition is attributed to the length of time each site has been undergoing succession, with the control site in a more advanced stage. Tradescantia grown in soil with a radiation dose greater than 0.10 mR/hr had significantly reduced reproductive integrity and fecundity, as measured by the number of stunted hairs on a stamen and poll en viability, and increased numbers of somatic mutations. Based on these data the radioactive mill tailings from the Vitro Chemical Plant have the potential to alter plant successional patterns due to their detrimental effect on any species that is relatively radiosensitive.

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