Paaskehegelund3364

The Trinity nuclear test, conducted in 1945, exposed residents of New Mexico to varying degrees of radioactive fallout. Companion papers in this issue have detailed the results of a dose reconstruction that has estimated tissue-specific radiation absorbed doses to residents of New Mexico from internal and external exposure to radioactive fallout in the first year following the Trinity test when more than 90% of the lifetime dose was received. Estimated radiation doses depended on geographic location, race/ethnicity, and age at the time of the test. Here, these doses were applied to sex- and organ-specific risk coefficients (without applying a dose and dose rate effectiveness factor to extrapolate from a population with high-dose/high-dose rates to those with low-dose/low-dose rates) and combined with baseline cancer rates and published life tables to estimate and project the range of radiation-related excess cancers among 581,489 potentially exposed residents of New Mexico. The total lifetime baseline number ethnicity groups for each cancer grouping. Thus, most cancers that have occurred or will occur among persons exposed to Trinity fallout are likely to be cancers unrelated to exposures from the Trinity nuclear test. While these ranges are based on the most detailed dose reconstruction to date and rely largely on methods previously established through scientific committee agreement, challenges inherent in the dose estimation, and assumptions relied upon both in the risk projection and incorporation of uncertainty are important limitations in quantifying the range of radiation-related excess cancer risk.Trinity was the first test of a nuclear fission device. The test took place in south-central New Mexico at the Alamogordo Bombing and Gunnery Range at 0529 AM on 16 July 1945. This article provides detailed information on the methods that were used in this work to estimate the radiation doses that were received by the population that resided in New Mexico in 1945. The 721 voting precincts of New Mexico were classified according to ecozone (plains, mountains, or mixture of plains and mountains), and size of resident population (urban or rural). Methods were developed to prepare estimates of absorbed doses from a range of 63 radionuclides to five organs or tissues (thyroid, active marrow, stomach, colon, and lung) for representative individuals of each voting precinct selected according to ethnicity (Hispanic, White, Native American, and African American) and age group in 1945 (in utero, newborn, 1-2 y, 3-7 y, 8-12 y, 13-17 y, and adult). Three pathways of human exposure were included (1) external irradiation from the radionuclides deposited on the ground; (2) inhalation of radionuclide-contaminated air during the passage of the radioactive cloud and, thereafter, of radionuclides transferred (resuspended) from soil to air; and (3) ingestion of contaminated water and foodstuffs. Within the ingestion pathway, 13 types of foods and sources of water were considered. Well established models were used for estimation of doses resulting from the three pathways using parameter values developed from extensive literature review. Because previous experience and calculations have shown that the annual dose delivered during the year following a nuclear test is much greater than the doses received in the years after that first year, the time period that was considered is limited to the first year following the day of the test (16 July 1945). Numerical estimates of absorbed doses, based on the methods described in this article, are presented in a separate article in this issue.The National Cancer Institute study of projected health risks to New Mexico residents from the 1945 Trinity nuclear test provides best estimates of organ radiation absorbed doses received by representative persons according to ethnicity, age, and county. Doses to five organs/tissues at significant risk from exposure to radioactive fallout (i.e., active bone marrow, thyroid gland, lungs, stomach, and colon) from the 63 most important radionuclides in fresh fallout from external and internal irradiation were estimated. The organ doses were estimated for four resident ethnic groups in New Mexico (Whites, Hispanics, Native Americans, and African Americans) in seven age groups using (1) assessment models described in a companion paper, (2) data on the spatial distribution and magnitude of radioactive fallout derived from historical documents, and (3) data collected on diets and lifestyles in 1945 from interviews and focus groups conducted in 2015-2017 (described in a companion paper). The organ doses were found toded to illustrate a lower and upper credible range on our best estimates of doses. Our findings indicate that only small geographic areas immediately downwind to the northeast received exposures of any significance as judged by their magnitude relative to natural radiation. The findings presented are the most comprehensive and well-described estimates of doses received by populations of New Mexico from the Trinity nuclear test.The Trinity nuclear test was detonated in south-central New Mexico on 16 July 1945; in the early 2000s, the National Cancer Institute undertook a dose and cancer risk projection study of the possible health impacts of the test. In order to conduct a comprehensive dose assessment for the Trinity test, we collected diet and lifestyle data relevant to the populations living in New Mexico around the time of the test. This report describes the methodology developed to capture the data used to calculate radiation exposures and presents dietary and lifestyle data results for the main exposure pathways considered in the dose reconstruction. Individual interviews and focus groups were conducted in 2017 among older adults who had lived in the same New Mexico community during the 1940s or 1950s. Interview questions and guided group discussions focused on specific aspects of diet, water, type of housing, and time spent outdoors for different age groups. Thirteen focus groups and 11 individual interviews were conducted amistant past seemed effective. These data were summarized, and together with other information, these data have been used to estimate radiation doses for representative persons of all ages in the main ethnic groups residing in New Mexico at the time of the Trinity nuclear test.The potential health consequences of the Trinity nuclear weapon test of 16 July 1945 at Alamogordo, New Mexico, are challenging to assess. Population data are available for mortality but not for cancer incidence for New Mexico residents for the first 25 y after the test, and the estimates of radiation dose to the nearby population are lower than the cumulative dose received from ubiquitous natural background radiation. Despite the estimates of low population exposures, it is believed by some that cancer rates in counties near the Trinity test site (located in Socorro County) are elevated compared with other locations across the state. Further, there is a concern about adverse pregnancy outcomes and genetic diseases (transgenerational or heritable effects) related to population exposure to fallout radiation. The possibility of an intergenerational effect has long been a concern of exposed populations, e.g., Japanese atomic bomb survivors, survivors of childhood and adolescent cancer, radiation workers, and environmentally exposed groups. In this paper, the likelihood of discernible transgenerational effects is discounted because (1) in all large-scale comprehensive studies of exposed populations, no heritable genetic effects have been demonstrated in children of exposed parents; (2) the distribution of estimated doses from Trinity is much lower than in other studied populations where no transgenerational effects have been observed; and (3) there is no evidence of increased cancer rates among the scientific, military, and professional participants at the Trinity test and at other nuclear weapons tests who received much higher doses than New Mexico residents living downwind of the Trinity site.The Trinity test device contained about 6 kg of plutonium as its fission source, resulting in a fission yield of 21 kT. However, only about 15% of the Pu actually underwent fission. The remaining unfissioned plutonium eventually was vaporized in the fireball and after cooling, was deposited downwind from the test site along with the various fission and activation products produced in the explosion. Using data from radiochemical analyses of soil samples collected postshot (most many years later), supplemented by model estimates of plutonium deposition density estimated from reported exposure rates at 12 h postshot, we have estimated the total activity and geographical distribution of the deposition density of this unfissioned plutonium in New Mexico. A majority (about 80%) of the unfissioned plutonium was deposited within the state of New Mexico, most in a relatively small area about 30-100 km downwind (the Chupadera Mesa area). For most of the state, the deposition density was a small fraction of the subsequent deposition density of Pu from Nevada Test Site tests (1951-1958) and later from global fallout from the large US and Russian thermonuclear tests (1952-1962). ER stress inhibitor The fraction of the total unfissioned Pu that was deposited in New Mexico from Trinity was greater than the fraction of fission products deposited. Due to plutonium being highly refractory, a greater fraction of the Pu was incorporated into large particles that fell out closer to the test site as opposed to more volatile fission products (such as Cs and I) that tend to deposit on the surface of smaller particles that travel farther before depositing. The plutonium deposited as a result of the Trinity test was unlikely to have resulted in significant health risks to the downwind population.

Inhalation of plutonium is a significant contributor of occupational doses in plutonium production, nuclear fuel reprocessing, and cleanup operations. Accurate assessment of the residence time of plutonium in the lungs is important to properly characterize dose and, consequently, the risk from inhalation of plutonium aerosols. This paper discusses the long-term retention of plutonium in different parts of the respiratory tract of two workers who donated their bodies to the US Transuranium and Uranium Registries. The post-mortem tissue radiochemical analysis results, along with the urine bioassay data, were interpreted using Markov Chain Monte Carlo and the latest biokinetic models presented in the Occupational Intakes of Radionuclides series of ICRP publications. The materials inhaled by both workers were found to have solubility between that of plutonium nitrates and oxides. The long-term solubility was also confirmed by comparison of the activity concentration in the lungs and the thoracic lymph nodes. Thed in the respiratory tract that becomes bound to lung tissue after dissolution) of 1% and 4%, respectively, without having to significantly alter the particle clearance parameters. Effects of different assumptions about the bound fraction on radiation doses to different target regions was also investigated. For inhalation of soluble materials, an assumption of fb of 1%, compared to the ICRP default of 0.2%, increases the dose to the most sensitive target region of the respiratory tract by 258% and that to the total lung by 116%. Some possible alternate methods of explaining higher-than-expected long-term retention of plutonium in the upper respiratory tract of these individuals-such as physical sequestration of material into the scar tissues and possible uptake by lungs-are also briefly discussed.