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Environmental Inhaled Agents and Their Relation to Lung Cancer
Published in Jacob Loke, Pathophysiology and Treatment of Inhalation Injuries, 2020
To control radiation levels in mines, the U.S. Public Health Service introduced the working level (WL) unit, which is defined as any combination of radon daughters in 1 liter of air that will result in emission of 1.3 X 105 million electron volts/liter of potential alpha energy. The measure of total radiation exposure of miners is expressed as a working level month (WLM), which is inhalation for 1 working month (170 hr) of air with a radon daughter concentration of 1 WL. Most authorities accept that no workers should have an exposure of more than 4 WLM a year (Parkes, 1982a). Efficient ventilation of the mine is essential, and radon daughter concentration in mine air should be monitored. At the iron mine in Malmberget, Sweden, (Radford and Renard, 1984), for instance, an extensive new ventilation system has resulted in annual exposures of less than 1 WLM, which represents a great improvement over past standards.
Radiation Hormesis in Cancer
Published in T. D. Luckey, Radiation Hormesis, 2020
When data from uranium miners was presented on a dose related basis, the ratio of observed/expected lung cancer deaths increased with dose (Figure 6.9).57 However, note the lowest cumulative dose considered. Fewer lung cancer deaths than expected were found for doses of 1 to 20 WLM (working level month is a complicated unit of radiation, mostly alpha rays, used for major radionuclides with progeny). The ZEP for this ratio was about 20 WLM. Note also, 230Th is considered to be 20 to 50 times more hazardous than uranium.35 Significant excess leukemia or solid tissue cancers were not found in this cohort. Excess deaths from other causes was found, suggesting no “healthy worker effect” in these white males.
Requirements and Preparation for Passing the American Board of Health Physics Certification Examinations
Published in Kenneth L. Miller, Handbook of Management of Radiation Protection Programs, 2020
Radon has been a subject of bitter controversy since the early 1980s and, according to the NCRP,101 is the dominant contributor to population exposure. Radon questions on the examinations are a virtual certainty and these questions are likely to call for detailed knowledge of Rn. It should be remembered, for example, that 222Rn is in the uranium series and that radon nuclides from other decay series are unimportant because of their short half-lives; the lung dose is almost all from the short-lived daughters 218Po, 214Pb, 214Bi, and 214Po; the “working level” (WL) is defined as the concentration of these daughters that would ultimately release 130,000 MeV/L; a WL is equivalent to daughters in equilibrium with 100 pCi/L 222Rn; a “working level month” (WLM) is exposure equivalent to 173 hr at 1 WL; the BEIR IV102 risk estimate of 350 cancer deaths per million WLM is about 2.7 times the NCRP estimate102 but is consistent with UNSCEAR 77103 and less than one half the BEIR III104 estimate; critics contend that the estimates should be given as “0 to the calculated value”,105 the EPA criterion for RN in homes is 4 pCi/L;106 methods of measuring Rn daughter concentrations include activated charcoal, alpha track-etch detectors, and electret systems; and Rn remains almost uniformly mixed in air even though Rn gas is more than seven times as dense as air.
Interaction between occupational radon exposure and tobacco smoke: a systematic review
Published in Expert Review of Respiratory Medicine, 2022
Giuseppina Folesani, Maricla Galetti, Silvia Ranzieri, Pier Giorgio Petronini, Silvia La Monica, Massimo Corradi, Delia Cavallo
Some definitions: ERR (excess relative death risk, defined as RR +1) was reported in the unit of mining industry, WLM (working level month);1 WLM was the concentration of short-lived decay products. One liter of radon in the air leading to the release of alpha particles with an energy of 1.3 × 105 MeV;WL was working level, for the month of work (working month; 170 h).The environmental exposure for radon was reported as the mean concentration of radon per cubic meter of air Bq/m3.WLM can be converted to 100 Bq/m3 assuming that 1 Bq/m3 is the equivalent of 0.00027 WL.
Cohort profile: four early uranium processing facilities in the US and Canada
Published in International Journal of Radiation Biology, 2021
Ashley P. Golden, Cato M. Milder, Elizabeth D. Ellis, Jeri L. Anderson, John D. Boice, Stephen J. Bertke, Lydia B. Zablotska
Of the ∼500,000 North American workers involved in nuclear fuel production (Bouville and Kryuchkov 2014), only 10–15% have been involved in uranium processing. These workers have been previously described in eight North American studies (Table 1) (Dupree et al. 1987; Dupree-Ellis et al. 2000; Pinkerton et al. 2004; Boice et al. 2007, 2008; Silver et al. 2013; Zablotska et al. 2013; Golden et al. 2019). These workers are a distinct group because their cumulative external gamma exposures are 4–5 times higher than those of nuclear workers (100 millisievert (mSv) vs. 20 mSv (Richardson et al. 2015)) and their RDP exposures are 4–5 times lower than those of uranium miners (20 working level months (WLM) vs. 90 WLM (Lubin et al. 1995)). Of these eight studies, we identified four cohorts with at least two of the following exposures necessary for risk estimation in a pooled analysis: assessed individual internal uranium, radium, RDP exposures, and external radiation doses. In this pooled analysis we included the Fernald Feed Materials Production Center in Ohio (Hornung et al. 2008; Anderson et al. 2012; Silver et al. 2013), Mallinckrodt Chemical Works Uranium Division in Missouri (Dupree-Ellis et al. 2000; Golden et al. 2019), the Middlesex Sampling Plant in New Jersey (Eisenbud 1975), and the Port Hope radium and uranium refinery and processing plant in Canada (Zablotska et al. 2013, 2018). The unifying feature of these four cohorts is that they all belonged to a network of plants that provided the uranium needed by the United States during World War II and the Cold War era (Eisenbud 1975).
Challenges in the quantification approach to a radiation relevant adverse outcome pathway for lung cancer
Published in International Journal of Radiation Biology, 2021
Robert Stainforth, Jan Schuemann, Aimee L. McNamara, Ruth C. Wilkins, Vinita Chauhan
Values of equivalent dose (Sv) were converted to absorbed dose (Gy) using the relevant radiation weighting factors defined by the International Commission of Radiation Protection (ICRP 2007). Radon exposure of the lungs reported in units of working level months (WLM) were converted to estimates of absorbed dose by using the recommended ICRP effective dose coefficient for mine and general indoor environments (=10 mSv/WLM; ICRP 2017), tissue weighting factor (=0.12 for the lungs), and radiation weighting factor (=20 for alpha-particles; ICRP 2007). Studies contributing to the WoE of NAd-KER7 were predominantly from occupational cohorts of miners that only provide a summary on the average career-span of a worker, and any lag-period, if any, following the end of employment for which a RR of lung cancer was assessed. In these cases, missing values of the dose rate were estimated as the ratio of the average dose and career-span. The exposure was therefore assumed chronic and constant. The time after exposure was estimated as the average career-span in addition to any lag-period following employment. Missing dose rate values for studies contributing to the upstream KEs for Ad-KER1, NAd-KER1, and NAd-KER2 could not be estimated using the same assumption as the nature of the radiation exposure in these studies was often acute.