Topic
Uranium Ore Dust
About: Uranium Ore Dust is a research topic. Over the lifetime, 25 publications have been published within this topic receiving 416 citations.
Papers
TL;DR: Evidence is presented that a two-stage stochastic model of carcinogenesis used to analyze lung tumor incidence in 3750 rats exposed to varying regimens of radon carried on a constant-concentration uranium ore dust aerosol describes the data adequately and generates hypotheses regarding the mechanism of Radon-induced carcinogenesis.
Abstract: A two-stage stochastic model of carcinogenesis is used to analyze lung tumor incidence in 3750 rats exposed to varying regimens of radon carried on a constant-concentration uranium ore dust aerosol. New to this analysis is the parameterization of the model such that cell killing by the alpha particles could be included. The model contains parameters characterizing the rate of the first mutation, the net proliferation rate of initiated cells, the ratio of the rates of cell loss (cell killing plus differentiation) and cell division, and the lag time between the appearance of the first malignant cell and the tumor. Data analysis was by standard maximum likelihood estimation techniques. Results indicate that the rate of the first mutation is dependent on radon and consistent with in vitro rates measured experimentally, and that the rate of the second mutation is not dependent on radon. An initial sharp rise in the net proliferation rate of initiated cell was found with increasing exposure rate (denoted model I), which leads to an unrealistically high cell-killing coefficient. A second model (model II) was studied, in which the initial rise was attributed to promotion via a step function, implying that it is due not to radon but to the uranium ore dust. This model resulted in values for the cell-killing coefficient consistent with those found for in vitro cells. An "inverse dose-rate" effect is seen, i.e. an increase in the lifetime probability of tumor with a decrease in exposure rate. This is attributed in large part to promotion of intermediate lesions. Since model II is preferable on biological grounds (it yields a plausible cell-killing coefficient), such as uranium ore dust. This analysis presents evidence that a two-stage model describes the data adequately and generates hypotheses regarding the mechanism of radon-induced carcinogenesis.
68 citations
TL;DR: An excess mortality from lung cancer due to radon exposure and from solid cancers due to external gamma radiation in uranium millers that was not statistically significant is shown.
Abstract: To examine exposure–response relationships between ionizing radiation and several mortality outcomes in a subgroup of 4,054 men of the German uranium miner cohort study, who worked between 1946 and 1989 in milling facilities, but never underground or in open pit mines. Mortality follow-up was from 1946 to 2008, accumulating 158,383 person-years at risk. Cumulative exposure to radon progeny in working level months (WLM) (mean = 8, max = 127), long-lived radionuclides from uranium ore dust in kBqh/m3 (mean = 3.9, max = 132), external gamma radiation in mSv (mean = 26, max = 667) and silica dust was estimated by a comprehensive job–exposure matrix. Internal Poisson regression models were applied to estimate the linear excess relative risk (ERR) per unit of cumulative exposure. Overall, a total of 457, 717 and 111 deaths occurred from malignant cancer, cardiovascular diseases and non-malignant respiratory diseases, respectively. Uranium ore dust and silica dust were not associated with mortality from any of these disease groups. A statistically significant relationship between cumulative radon exposure and mortality from all cancers (ERR/100 WLM = 1.71; p = 0.02), primarily due to lung cancer (n = 159; ERR/100 WLM = 3.39; p = 0.05), was found. With respect to cumulative external gamma radiation, an excess of mortality of solid cancers (n = 434; ERR/Sv = 1.86; p = 0.06), primarily due to stomach cancer (n = 49, ERR/Sv = 10.0; p = 0.12), was present. The present findings show an excess mortality from lung cancer due to radon exposure and from solid cancers due to external gamma radiation in uranium millers that was not statistically significant. Exposure to uranium was not associated with any cause of death, but absorbed organ doses were estimated to be low.
62 citations
TL;DR: The methodology and dosimetric models used to calculate these organ doses are described and the resulting doses for unit exposure to each source (radon gas, radon progeny and LLR) are presented.
Abstract: Epidemiological studies on uranium miners are being carried out to quantify the risk of cancer based on organ dose calculations. Mathematical models have been applied to calculate the annual absorbed doses to regions of the lung, red bone marrow, liver, kidney and stomach for each individual miner arising from exposure to radon gas, radon progeny and long-lived radionuclides (LLR) present in the uranium ore dust and to external gamma radiation. The methodology and dosimetric models used to calculate these organ doses are described and the resulting doses for unit exposure to each source (radon gas, radon progeny and LLR) are presented. The results of dosimetric calculations for a typical German miner are also given. For this miner, the absorbed dose to the central regions of the lung is dominated by the dose arising from exposure to radon progeny, whereas the absorbed dose to the red bone marrow is dominated by the external gamma dose. The uncertainties in the absorbed dose to regions of the lung arising from unit exposure to radon progeny are also discussed. These dose estimates are being used in epidemiological studies of cancer in uranium miners.
48 citations
1 Jan 1974
TL;DR: In this paper, rats were exposed to several dose levels of radon at different levels of equilibrium with radon decay products, after inhalation of stable cerium hydroxide, and in combination with uranium ore dust.
Abstract: To investigate the dose-effect relationships, rats were exposed to several dose levels of radon at different levels of equilibrium with radon decay products, after inhalation of stable cerium hydroxide, and in combination with uranium ore dust.
36 citations
TL;DR: Significantly greater activity levels of 234U and 238U were measured in both urine and fecal samples obtained from uranium mill crushermen, indicating that uranium in the inhaled ore dust was cleared from the body with a shorter biological half-time than the daughter product 230Th.
Abstract: Pacific Northwest Laboratory conducted a research program to measure uranium and thorium levels in excreta of uranium mill crushermen who are routinely exposed to airborne uranium ore dust. The purpose of this work was to determine whether 230Th was preferentially retained in the body over either 234U or 238U. Urine and fecal samples were obtained from 14 active crushermen with long histories of exposure to uranium ore dust, plus four retired crushermen and three control individuals for comparison. Radiochemical procedures were used to separate out the uranium and thorium fractions which were then electroplated on stainless steel discs and assayed by alpha spectrometry. Significantly greater activity levels of 234U and 238U were measured in both urine and fecal samples obtained from uranium mill crushermen, indicating that uranium in the inhaled ore dust was cleared from the body with a shorter biological half-time than the daughter product 230Th. The measurements also indicated that uranium and thorium separate in vivo and have distinctly different metabolic pathways and transfer rates in the body.
30 citations
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Performance Metrics
| Year | Papers |
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| 2017 | 1 |
| 2015 | 1 |
| 2012 | 1 |
| 2011 | 1 |
| 2008 | 1 |
| 2003 | 1 |