Theses and Dissertations at Montana State University (MSU)
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Item Radiocesium in Montana soils and applications for soil erosion measurement(Montana State University - Bozeman, College of Agriculture, 1984) Arnalds, Olafur Gestur; Chairperson, Graduate Committee: Gerald A. NielsenRadiocesium levels in soils were measured at eleven sites throughout Montana. Cesium was mostly confined to the top of the soil profile. Both lateral and vertical displacement of cesium was attributed to mechanical movement of soil particles. The areal activity of cesium was strongly correlated to annual precipitation (R^2 = 0.92). An equation is given to predict cesium activity from annual rainfall. Methods of calculating soil erosion and deposition are discussed and performed for a wind erosion study site in Pondera County and a small watershed in Teton County. The results indicate that deposition at the wind erosion study site can be quantified. Soil deposition of 70 to 1290 m^3 ha^-1 was measured on the leeward sides of a fence and tree windbreaks while an average of 450 m^3 was lost from the windward sides. An average of 740 m^3 ha^-1 was lost since 1962 from an adjacent wind eroded field. This amounts to 34.8 Mg ha^-1 yr^-1. Soil loss since about 1962 ranged from 300 to 820 m^3 ha^-1 within the upper areas of the watershed studied. A pond at the outlet of the watershed and deposition areas at the toeslope accounted for a relatively small fraction of the soil loss within the watershed. Most of the losses are likely to be from wind erosion. Length of slopes or position within the field were more related to erosion than was steepness of slopes, Estimates of erosion rates based on 137Cs ranged from 16.5 Mg ha^-1 yr^-1 at the summit of the watershed to 45.1 Mg ha^-1 yr^-1 at the midslope. Predictions by conventional methods (wind erosion equation and the Universal Soil Loss Equation) agreed rather closely with the estimates from 137Cs.Item Radiation ecologies : bombs, bodies, and environment during the atmospheric nuclear weapons testing period, 1942-1965(Montana State University - Bozeman, College of Letters & Science, 2013) Jessee, Emory Jerry; Chairperson, Graduate Committee: Michael Reidy; Tim LeCain (co-chair)From 1945 to 1963 the United States Atomic Energy Commission detonated over 200 nuclear weapons tests at its Nevada and Pacific test sites, irradiating every living thing on the planet. Much of the historical scholarship on the period has focused on the scientific debate over the health effects of low-level radiation exposure or on determining what and when the Atomic Energy Commission knew about the health effects fallout. This dissertation, however, argues that the growth of ecological thinking about the health effects of fallout exposure in environmental sciences such as ecology, oceanography, and meteorology dramatically reshaped what was known about radiological risk and provided the scientific foundation for the Limited Test Ban Treaty. By highlighting the ways that radiation traveled beyond the boundaries of the test sites and became incorporated into critical human food chains, this ecological way of perceiving fallout largely replaced previous approaches to fallout risks derived from the discipline of health physics that focused on external forms of radiation exposure and ideas of spatial containment. This dissertation, however, also argues that fallout radiation proved much more than a menacing pollutant. Because environmental scientists can utilize radiation as a tool to trace out structure and function of the ecosystem, as well as oceanic and atmospheric motions, it also emerged during this period as a critical scientific practice. In tracing radiation as it moved through the environment, environmental scientists not only made legible the connections between the health of human bodies and the irradiated environment, but also demonstrated empirically that the earth was a spatially integrated biosphere. Such realizations, this dissertation concludes, formed an important footing the nascent environmental movement and helped establish the authority of the environmental sciences in matters of environmental pollution and regulation.