This study investigates the level of technological enhancement of normally occurring radioactive materials (TENORM) in the red mud waste due to the production of alumina in Jamaica. Technological enhancements factors (TEF) were determined for the uranium, thorium, actinium series, their progenies, and the nonseries potassium-40 using gamma spectrometry. The study concluded that bauxite production technologically enhances the uranium progenies Th-234, Pb-214, Bi-214, and Pa-234 and the thorium-232 progenies Ac-228, Pb-212, and Bi-212 in red mud. The actinium series was technologically enhanced, but K-40 and the thorium daughter, Tl-208, were reduced. The spectrometric comparison of Tl-208 (at 510 keV) was unexpected since its other photopeaks at 583 keV, 934 keV, and 968 keV were markedly different. An explanation for this anomaly is discussed. An explanation regarding the process of accumulation and fractionation of organically derived phosphate deposits and potassium-feldspar is offered to explain the spectrometric differences between the alumina product and its waste material, red mud.
In this work, statistics and geospatial analysis are used to investigate the hypothesis that either bauxitic soils or underlying geology increases the carcinogenic health risks to the population due to exposure from naturally occurring radioactive materials (NORM) in the soil environment over which they reside. The rationale for this study is the large distribution of bauxitic soils in Jamaica and a review of the last published 5-year cancer survey study of Jamaica. A negative health environment was defined as one where the excess lifetime cancer risk (ELCR) value exceeded the world mean value of 2.9×10 −4 and the annual gonadal dose equivalent (AGDE) was a multiple of the acceptable level of 300 μSv/ year. The excess lifetime cancer risk index in Jamaica ranges from 0.16×10 −5 to 7.92×10 −4 with a mean value of 1.63×10 −4. The mean value of the ELCR index in Jamaica was statistically significantly lower than the world mean value. The main areas of concern were the sections of the parishes of Manchester and St. Elizabeth which exhibited value of up to five (5) times the acceptable level of the ELCR index. The AGDE index showed a moderate correlation of 0.511 with a reclassified geology group (limestone and non-limestone) introduced in this study. The soils overlaying limestone formations in Jamaica were characterized by a statistically significantly higher dose rate exposure to the gonads of the population. Geological explanations for the levels of the primordial radionuclides are also discussed in this paper. The results suggested that limestone geology in Jamaica had a significantly higher mean value for both indices (ELCR and AGDE) when compared to other geologies. Since bauxitic soils predominantly overlay these rocks in Jamaica, the research hypothesis regarding the impact bauxitic soils is supported by the results of this study. The impact of geology was not significant, and probable causes are discussed.
The objective of this study is to model the impact of uncertainties in the engineering specifications of a typical p-type HPGe detector on the efficiency values when the measured soil sample is in contact geometry with the detector. We introduce a parameter named the normalized sensitivity impact which allows a comparative analysis to be made of the impact of the detector specification uncertainties and develop a correction factor table for the most important parameters. The areas of the detector most susceptible to error were found to be the crystal geometry, vacuum layer above the crystal and the bulletizing radius. In all cases the major impacts were mathematically modeled - for the first time - and found to vary either quadratically or logarithmically over the energy range of 180 keV to 1500 keV. Finally, we propose a set of detector characterization values that may be used in ANGLE for generating a reference efficiency curve using the efficiency transfer method inherent in this software. These values are to be used with the understanding that their uncertainty impact on the full-peak efficiency though not very significant in this counting arrangement, is not non-zero
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.