|ognizant Communication Corporation|
A Journal of Science Serving Legislative, Regulatory, and Judicial Systems
Human Advancement · Environmental Protection · Industrial Development
TABLES OF CONTENTS
Volume 7, Numbers 2-4
Technology, Vol. 7, pp. 145-155, 2000
1072-9240/00 $20.00 + .00
Copyright © 2000 Cognizant Comm. Corp.
Printed in the USA. All rights reserved.
The Role of Merril Eisenbud and HASL in Monitoring the Marshall Islands During the Castle Nuclear Testing Series
Steven L. Simon
Board on Radiation Effects Research, National Academy of Sciences, National Research Council, 2101 Constitution Ave. NW, Washington, DC 20418
What little quantitative information is known today about the level of exposures of Marshallese from the BRAVO test and the other Castle series nuclear tests came from the Pacific Ocean radiological monitoring program conducted by the Health and Safety Laboratory (HASL) of the U.S. Atomic Energy Commission under the direction of Merril Eisenbud. The methods used by HASL included gummed paper and pot fallout collectors, stationary continuous reading exposure rate meters, and aerial surveys of the islands and ocean using then state-of-the-art scintillometer-type instruments. The objective of this article is to discuss some of the history of the HASL monitoring program, the strategies required and instruments used, and provide information about BRAVO that was only brought to light by Eisenbud's historical accounts. Finally, a summary of the 1994 Congressional Oversight Hearings into the BRAVO incident is presented. The purpose of this discussion is to shed light on the enormous contribution to protection of the Marshallese that should be attributed to Eisenbud.
Key words: Eisenbud; BRAVO; HASL; Marshall Islands; Rongelap; Atomic tests; Fallout
Address correspondence to Steven L. Simon. Tel: (202) 334-2232; Fax: (202) 334-1639; E-mail: email@example.com
Merril Eisenbud and the Beryllium Saga
J. Newell Stannard
University of California, San Diego, La Jolla, CA
The light metal, beryllium, has had many uses in industry (e.g., in alloys, in ceramics, in phosphors for fluorescent lamps, and in the nuclear industry). It has also presented some serious and puzzling health problems. This contribution reviews the saga of these effects, their possible explanations, and the part played by Merril Eisenbud in unraveling them. In the 1920s or 1930s, attention focused primarily on an acute pneumonitis thought to be caused by the caustic vapors in the extraction processes. Later these acute effects were considered to be due, at least in part, to certain forms of beryllium. By the early 1940s a chronic form of the disease appeared in fluorescent lamp workers, in beryllium processing plants, and in a surrounding neighborhood. These two forms of the disease became a major concern of industrial hygienists. The attack was spearheaded by Merril Eisenbud and continued throughout his career. There resulted one of the first documented instances of effluents from an industrial plant causing a specific disease in its neighborhood, standards for both occupational and environmental exposures to beryllium, and evidence that chromic beryllium disease had an immunological basis.
Key words: Merril Eisenbud; Beryllium; Health-related problems; Environmental effects
Address correspondence to J. Newell Stannard, 17446 Plaza Dolores, San Diego, CA 92128-2243. Tel: (619) 487-4204; Fax: (619) 487-4670.
Scientific and Administrative History of the United States Transuranium and Uranium Registries
Ronald L. Kathren
Washington State University, 2710 University Drive, Richland, WA 99352-1671.
This article documents the administrative and scientific history of the United States Transuranium and Uranium Registries, since their inception as the National Plutonium Registry in 1968. The Registries are a unique postmortem human tissue research program studying the biokinetics, dosimetry, and possible biological effects in persons with known intakes of plutonium, uranium, and the other actinide elements. The scientific evolution of the program over its three-decade history is traced through brief discussion of some of the more significant scientific findings of the Registries, including contributions to biokinetic modeling, and bioeffects.
Key words: U.S. Transuranium and Uranium Registries; Actinide elements; Biokinetic modeling; Bioeffects
Address correspondence to Ronald L. Kathren, 137 Spring Street, Richland, WA 99352. Tel: (509) 375-3316; Fax: (509) 375-5643.
Radon Risk Assessment: A Perspective Across the Century
Jonathan M. Samet
Department of Epidemiology, School of Hygiene and Public Health, Johns Hopkins University, 615 N. Wolfe St., Suite 6041, Baltimore, MD 21205
Radon was one of the many environmental agents that Merril Eisenbud addressed during his career, and he was an early advocate of limiting worker exposure to this carcinogen. This article focuses on the evolution of approaches for estimating the risk of radon for the purpose of protecting workers and the public in general. The first risk evaluations drew qualitatively on the lung cancer problem in the European miners. As lung dosimetry for radon and radon progeny sharpened, dosimetric approaches were used. These have been supplanted by risk models based on epidemiologic studies of underground miners. To date, risk models based on the evidence from miners have been the foundation for estimating the risks of indoor radon. With expanding epidemiologic evidence and increasingly sophisticated statistical methods for data analyses, models for radon and lung cancer risk have become increasingly useful and credible. This article concludes by observing that more than 59 years after Merril Eisenbud cautioned against radon-caused lung cancer in underground miners and warned public health officials of the need to limit worker exposure, the principal evidence for estimating the lung cancer risk of radon progeny exposure now comes from studies of uranium and other underground miners.
Key words: Radon; Radon progeny; Risk assessment; Carcinogen; Epidemiology
Address correspondence to Jonathan M. Samet. Tel: (410) 955-3286; Fax: (410) 955-0863; E-mail: firstname.lastname@example.org
More Than Forty Years of Studies of Natural Radioactivity in Brazil
Anselmo S. Paschoa
Pontifícia Universidade Católica do Rio de Janeiro, Departamento de Física, C.P. 38071, Rio de Janeiro, RJ 22452-970, Brazil
The studies of natural radioactivity in Brazil started more than 90 years ago, when the thermal mineral waters of Poços de Caldas were assessed for their radioactivity. Forty years later a broader study was started, conducted jointly by investigators of the Instituto de Biofísica of the Universidade Federal do Rio de Janeiro (IB/UFRJ), formerly Universidade do Brasil (IB/UB), Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio), Museu Nacional (MN), and New York University (NYU), among other scientific institutions and governmental agencies of Brazil and the United States. Merril Eisenbud, a member of the United States delegation to the first meetings of the United Nations Scientific Committee on the Effects of Atomic Radiation, which occurred in 1955, was the implausible catalytic element in the scientific association of two physicist priests, Frans X. Roser, S.J. and Thomas L. Cullen, S.J., in addition to helping investigators from several Brazilian institutions improve their scientific formation and careers. This article will present an overview of the earlier studies of natural radioactivity in Brazil concerned mostly with mineral waters, as well as those undertaken later in the Brazilian regions of high natural radioactivity. The origins of the "Morro do Ferro project" concerning the concept of thorium as an analogue for plutonium will also be briefly discussed. Merril Eisenbud's initiative and overall support helped to make possible most of the studies on the Brazilian areas of high natural radioactivity that were carried out after 1955.
Key words: Natural radioactivity; Brazil; Mineral waters
Address correspondence to Anselmo S. Paschoa. Tel: 55 21 529 9479; Fax: 55 21 259 9397; E-mail: email@example.com
Is There a Role for Chelation in the Management of Chronic Beryllium Disease?*
Merril Eisenbud1 and Raymond A. Guilmette2
1Professor Emeritus, Nelson Institute of Environmental Medicine,
New York University Medical Center, Department of Environmental Sciences
2Lovelace Respiratory Research Institute (LRRI), Albuquerque, NM
The chronic form of lung disease seen in beryllium workers has not fully responded to conventional methods of occupational disease control. This is because of the immunopathological basis of chronic beryllium disease (CBD). Innovative methods of control are needed, and this article discusses whether chelating agents should be considered as a preventive or therapeutic strategy. The use of chelation for treatment of beryllium disease was studied experimentally for a while but ceased in the 1950s. Ethylenediaminetetraacetic acid (EDTA), currently used in pediatric practice for lead detoxification, has been shown in two very limited clinical experiments to markedly increase urinary excretion of beryllium in three cases of CBD. More efficacious and safer chelating compounds are needed and should be developed. Because the target organ is the lung, the chelate could be administered in relatively low doses by inhalation. Whether chelation can be useful for CBD prevention or therapy remains to be shown.
Key words: Beryllium disease; Chelation; EDTA
Address correspondence to Raymond A. Guilmette, Lovelace Respiratory Research Institute, P.O. Box 5890, Albuquerque, NM 87185. Tel: (505) 845-1096; Fax: (505) 845-1198; E-mail: firstname.lastname@example.org
*This original paper by Prof. Eisenbud was provided to Lovelace scientists in 1997 for our comment and participation. Although we were not able to complete the manuscript before Prof. Eisenbud's untimely death, this dedicated issue has afforded us the opportunity to do so. As such, Dr. Guilmette undertook to recraft the original paper according to the comments of the peer reviews. His contributions, together with important intellectual and editorial input from LRRI colleagues, Drs. Gregory L. Finch and Mark D. Hoover, were mainly in the areas of chelation and decorporation therapy, and the elucidation of the working hypothesis for beryllium chelation research. We are honored to be able to bring Merril's intriguing and provocative ideas to publication.
Human Health and the Environment: Progress, Problems, and Prospects
Arthur C. Upton
Clinical Professor of Environmental and Community Medicine, UMDNJ-Robert
Wood Johnson Medical School
Professor Emeritus of Environmental Medicine, New York University Medical School
Advances in nutrition, sanitation, and public health during the past century have dramatically improved the health of populations in industrialized countries, in which the major causes of disability and death are now cardiovascular diseases, cancer, and other chronic disorders. Because the latter are being linked increasingly to extrinsic, or "environmental" factors, strategies to identify such risk factors and develop means for their control have come to the fore in public health. The methodologies employed in such strategies, problems that have limited their effectiveness thus far, and some of the pertinent research needs are surveyed briefly in this article.
Key words: Human health; Environmental factors; Risk factors; Control strategies
Address correspondence to Arthur C. Upton, M.D.; 401 E. 86 St.; Apt. 12B, New York: NY 10028. Tel: (732) 235-9606; Fax: (732) 235-9607.
Risk Assessment and Screening Strategies for Beryllium Exposure
Scott M. Bartell,1,2 Timothy K. Takaro,2,3 Rafael A. Ponce,1,2 Juliane P. Hill,1 Elaine M. Faustman,1,2 and Gilbert S. Omenn4
1Department of Environmental Health and Institute for Risk
Analysis and Risk Communication, University of Washington, 4225 Roosevelt
Way NE #100, Seattle,
2Consortium for Risk Evaluation with Stakeholder Participation (CRESP), University of Washington, Seattle, WA
3Department of Medicine, University of Washington, Seattle, WA
4School of Medicine and School of Public Health, University of Michigan, Ann Arbor, MI
Respirable beryllium is a potent toxicant that can cause pulmonary granulomas and inflammation in exposed individuals. These effects, known as chronic beryllium disease (CBD), occurred in 1-3% of all beryllium workers and in 4-11% of beryllium machinists and ceramics workers in recent investigations. Decades ago, Merril Eisenbud and his colleagues conducted early epidemiologic research to improve the understanding of CBD risks at low levels of beryllium exposure. Today, CBD continues to pose a challenge to industrial hygienists, toxicologists, and other health professionals and researchers seeking to understand and mitigate this difficult to treat but clearly preventable disease. We discuss current approaches for assessing and managing CBD risk, and highlight current research efforts that may improve our understanding of CBD. Special emphasis is given to the role of genetics in CBD development, the use of immunologically based lymphocyte proliferation testing (LPT) in occupational health surveillance and risk management, and the social, legal, and ethical challenges posed by this information in forming appropriate preventive strategies.
Key words: Chronic beryllium disease (CBD); Lymphocyte proliferation testing (LPT); Polymorphism; Occupational health; Berylliosis
Address correspondence to Scott M. Bartell. Tel/Fax: (530)758-5481; E-mail: email@example.com
The Potential Impact of Cellular and Molecular Biology on Radiation Risk Assessment
Antone L. Brooks
Washington State University, Tri-Cities, 2710 University Drive, Richland, WA 99352-1643
Modern molecular and cellular biology has made it possible to detect and evaluate changes induced by low-level radiation exposures that can be used to supplement epidemiological approaches in risk assessment. If the mechanism of action for the induction of damage changes as a function of dose, or if there are interactions between the cells that repair or minimize the damage at lower doses, then potential statistical, biological, or energy barriers may exist. If these barriers exist, then extrapolation using linear-no-threshold assumptions needs to be reevaluated. Biological and technological advances may help determine if such thresholds or barriers exist and should be considered in risk assessment. The biological responses reviewed in this article that may impact risk involve DNA damage and repair, thresholds for exposure-response relationships, genetic sensitivity, bystander effects, adaptive response, and genomic instability. Efforts need to be made to incorporate the information derived from mechanistic studies, conducted at low doses, into epidemiological studies. Such information and understanding will aid in risk assessment. The biological basis of these low-level effects is discussed, and the potential implications for estimation of risk is reviewed.
Key words: Radiation; Risk assessment; Molecular biology; Cellular biology
Address correspondence to Antone L. Brooks. Tel: (509) 372-1912; Fax: (509) 372-1204; E-mail: firstname.lastname@example.org
A Look at the Increasing Complexity of ICRP Respiratory Tract Models and the Effect on Dose Calculations
W. J Bair
Pacific Northwest National Laboratory, Richland, WA 99352
In the last 40 years the International Commission on Radiation Protection (ICRP) has used a succession of three mathematical models to calculate radiation doses to the lungs and other tissues in the body after intakes of airborne radioactive particles. Each model, after the first, has been increasingly complex, partly in response to changing needs of the ICRP but also to incorporate new knowledge. Research that yielded this new knowledge was stimulated by deficiencies that became apparent as the previous model was used and tested. In a limited comparison, doses calculated with the most recent model are generally less, one half to one fourth those calculated with the previous model, and two to four times greater than those calculated with the first ICRP model. These relatively small differences suggest that radiation dose estimates are not greatly sensitive to which respiratory tract model is used. The major benefit of revising models of the respiratory tract is the increased confidence that is achieved by more accurate simulation of respiratory processes and the decreased uncertainty associated with the results.
Key words: International Commission on Radiation Protection (ICRP); Respiratory tract models; Dose calculations
Address correspondence to W. J Bair. 102 Somerset Street, Richland, WA 99352. Tel: (509) 375-0205.
The Fernald Dosimetry Reconstruction Project
John E. Till,1 George G. Killough,2 Kathleen R. Meyer,3 Warren K. Sinclair,4 Paul G. Voillequ,5 Susan K. Rope,6 and Marilyn J. Case7
1Risk Assessment Corporation, 417 Till Rd., Neeses, SC 29107
2Hendecagon Corporation, 105 Netherlands Rd., Oak Ridge, TN 37830
3Keystone Scientific Inc., 5009 Alder Ct., Ft. Collins, CO 80525
4Warren K. Sinclair, Inc., 236 Tampico Glen., Escondido, CA 92025
5MJP Risk Assessment, Inc., 591 Park Ave., Suite 301, Idaho Falls, ID 83405
6Environmental Perspectives, Inc., 5800 South Marbrisa Lane, Idaho Falls, ID 83406
7Eagle Rock Scientific, Inc., 2804 Meadowlark Lane, Idaho Falls, ID 83402
This article summarizes the methods and results of estimation of dose and risk of fatal cancer resulting from releases of radionuclides from 38 years of operations at the Fernald Feed Materials Production Center (FMPC) near Cincinnati, OH. The key findings show that people who lived near the facility were exposed to the radioactive decay products of radon and to uranium. Radon decay products contributed most of the radiation dose from past FMPC releases, which were highest before 1980. The organs receiving the highest equivalent radiation doses were, in order, lung, bone surfaces, red marrow, kidney, and liver. Nine exposure scenarios were developed to give a sense of the relationship between the doses and risks and various modes of exposure to the Fernald releases. Distance from the FMPC was the most important determinant of the exposure. More than 95% of the total risk is given by the risk of lung cancer. Depending on the scenario, the median, or 50th percentile, estimate of the lifetime risk of fatal lung cancer ranges from 0.11% to 1.3%. There is a small chance of a risk as high as 9.6% (highest exposure scenario, 95th percentile) or as low as 0.02% (lowest exposure scenario, 5th percentile). The median risk (1.3%) for the highest exposure scenario is about the same risk attributed to the average background radiation exposure over a lifetime (1.25%). The possibility of chemical toxicity from uranium in the human kidney is possible for two scenarios investigated, but these effects are based on inferred rather than directly known clinical or occupational data.
Key words: Fernald Dosimetry Reconstruction Project; Cancer risk; Radionuclides; Radon; Uranium
Address correspondence to John E. Till. Tel: (803) 536-4883; Fax: (803) 534-1995.
Studies of 239Pu in Beagles at the University of Utah
Ray D. Lloyd
University of Utah, Radiobiology Division, Department of Radiology, 729 Arapeen Drive, 2334 CAMT, Salt Lake City, UT 84108-1218
Effects of injected monomeric 239Pu in the beagle, a relatively long-lived mammal with a skeleton more similar to the human than is a rodent, have been studied in our laboratory for more than 45 years. For relatively low doses and dose rates as might be typical of environmental and industrial exposures, we have found that 1) juvenile and mature adult beagles appear to be less sensitive to 239Pu-induced skeletal malignancies than those exposed as young adults; 2) male and female beagles appear equally sensitive to bone cancer induction by Pu exposure; 3) exposure of endosteal surfaces within bone from a continuous influx of 239Pu is more carcinogenic in the beagle than is an equal radiation dose from the deposition of Pu received in a single exposure; 4) established tumorigenic effects in human bone from incorporated 226Ra and the Pu/Ra toxicity ratio of 16 determined in beagles and mice can be used to predict Pu effects in man; 5) bone tumor experience in humans injected repeatedly with 224Ra for a year or more can be extended to exposure of the skeleton to 239Pu; 6) liver cancer is inducible by Pu exposure, and the risks to man can be estimated from experience already documented in persons injected with colloidal 232Th (Thorotrast); 7) neoplastic effects of Pu exposure in soft tissues other than liver seem not to be of major concern; and 8) Pu-induced bone fractures are of much less importance than skeletal malignancy at low doses and dose rates. These findings also may be true in man.
Key words: Plutonium; Radiotoxic effects; Beagles; Skeletal malignancies; Carcinogenesis
Address correspondence to Ray D. Lloyd. Tel: (801) 581-6810; E-mail: email@example.com
Reassessment of Cancer Mortality Among Employees at Oak Ridge National Laboratory With Follow-Up Through 1984: A Comparison With Results of Previously Published Studies
C. Suzanne Lea,1 P. A. Buffler,1 M. J. Durst,2 D. W. Merrill,2 and S. Selvin1,2
1School of Public Health, 140 Warren Hall, University of
California, Berkeley, Berkeley, CA 94720
2Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720
An earlier study of a cohort of nuclear workers at Oak Ridge National Laboratory (ORNL) showed an elevated cancer risk in male workers. This study reanalyzed existing cohort data to more fully understand results of mortality analysis at ORNL and are discussed within the context of other reanalyses of the ORNL data. The cohort includes 8318 white male workers employed between January 1, 1943 and December 31, 1972 with follow-up for vital status through December 31, 1984. There were 1523 deaths from all causes, 379 cancer deaths, and 213,950 person-years of follow-up. Poisson regression generated mortality risk estimates. Mean cumulative dose in the cohort was 17.1 mSv. Cumulative dose was significantly associated with solid cancer mortality in the ORNL cohort (ERR = 1.7, 95% CI 0.4-3.0, lag = 10). However, after removing two individuals who died of smoking-related cancers receiving over 500 mSv cumulative dose, which is comparable to doses received by atomic bomb survivors, the solid cancer risk of mortality associated with cumulative dose was no longer significant (ERR = 0.9, 95% CI -0.8-2.6). The greater number of cumulative dose categories used to estimate all-cancer mortality risk resulted in smaller risk estimates for all-cancer mortality. Using four cumulative dose categories, the mortality risk estimate was 2.5, whereas with 13 categories of cumulative dose, the mortality risk estimate was 1.7 for the estimated percent increase in all-cancer mortality per 10 mSv increase in cumulative dose. Inclusion of contributory deaths from cancer determined from the death certificate (n = 34), as well as the cohort eligibility criteria (30 days or more vs. 6 months or more), also influenced the all-cancer mortality risk estimates. These factors appear to explain much of the excess cancer mortality findings reported in the 1991 publication of mortality at ORNL.
Key words: Cancer mortality; Occupational epidemiology; Reassessment; Oak Ridge National Laboratory
Address correspondence to C. Suzanne Lea, Ph.D., 1141 Clarendon Crescent, Oakland, CA 94610. Tel: (415) 554-9341; E-mail: firstname.lastname@example.org
Sources of 210Pb in Bone of Former Uranium Miners: Reference Values and Uncertainties
Richard W. Leggett1 and R. A. Guilmette2
1Life Sciences Division Division, Building 1060COM, MS 6480,
Oak Ridge National Laboratory, Oak Ridge, TN 37831-6480
2Inhalation Toxicology Research Institute, Albuquerque, NM 87185
The content of the long-lived radon daughter, 210Pb, in bone has been proposed as a measure of occupational intake of short-lived radon daughters by uranium miners. The problem arises that the contribution of occupational intake of radon daughters to current skeletal 210Pb may vary substantially from one subject to another, depending on mining conditions, diet, smoking habits, and other factors. A model is constructed to account for the total 210Pb content in the skeleton in terms of occupational 210Pb sources as well as nonoccupationally derived 210Pb. Reference values are proposed for all parameters, and uncertainties in the application of these reference values to individual subjects are discussed.
Key words: Radon daughters; Uranium miners; Occupational intake; 210Pb
Address correspondence to Richard W. Leggett. Tel: (865) 576-2079; E-mail: email@example.com
Presumptions in Radiation Protection
Harald H. Rossi*
105 Larchdale Ave., Upper Nyack, NY 10960
Protection against ionizing radiation has been impeded by sparsity of information on the effects of low doses. There are no scientifically acceptable theoretical downward extensions of the epidemiological findings at higher doses. The International Commission of Radiological Protection (ICRP) has not only made the assumption that the required extrapolation is linear but has attempted to justify this assumption in the face of contradictory radiobiological evidence of nonlinearity. There are instances where there is a threshold of carcinogenesis at small doses and in some cases even a reduction of the normal cancer incidence. The principal source of epidemiological information is data from the Japanese A-bomb survivors. It is apparent that an approximate linear dose-effect relation is based on erroneous dosimetry and that the required corrections must introduce nonlinearity for radiation. Long-term acceptance of ICRP recommendation by government agencies makes the scientifically indicated need for change a political issue and it may be expected that this will cause major delays of reform.
Key words: Ionizing radiation; Radiation effects; Dose-effect relation; Protection
*The author passed away on January 1, 2000
Mortimer M. Elkind
Department of Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523
Since Roentgen's discovery of the X-ray in 1895, scientists and society in general have been continuously impressed and surprised by its properties. Impressiveness reflects mainly the many applications that have been devised for X-rays in science, industry, and medicine. Historically, X-radiation also has been surprising because of its biological properties. Early in their application large doses of X-rays frequently were used, the negative consequences of which, if there were any, followed soon thereafter. Reducing the exposure did not always eliminate the surprises but just postponed them. They took longer to appear, often obscuring effect from cause. In the case of radiation-induced breast cancer, for example, latencies of 10-40 years have been recorded. Hence, to attribute this type of cancer to radiation as its particular cause, one must consider exposures that might have been received effectively in the distant past. The model to be described attributes a significant fraction of the current incidence of breast cancer to radiation administered many years in the past. Deficient repair is hypothesized to be responsible for the accumulation of radiation damage over time.
Key words: Breast cancer; Radiation damage; X-rays
Address correspondence to Mortimer M. Elkind. Tel: (970) 491-6674; Fax: (970) 491-0623; E-mail: firstname.lastname@example.org
André Bouville1 and Harold L. Beck2*
1National Cancer Institute, Radiation Epidemiology Branch,
EPS 7094, Bethesda, MD 20892
233 Greenwich Avenue, New York, NY 10014
This article reviews the role Merril Eisenbud played in establishing the first worldwide fallout monitoring network. This network, which used gummed-film as a detector, provided important data on the paths of fallout clouds originating at the Nevada Test Site during the 1950s and the relative fallout at various locations. Later reanalysis of the data allowed quantitative estimates to be made of the deposition of individual radionuclides for use in the retrospective dose assessments carried out during the 1980s and 1990s.
Key words: Fallout monitoring; Gummed-film network; Nuclear weapons tests
Address correspondence to André Bouville. Tel: (301) 594-7655; E-mail: email@example.com
*Formerly Director, Environmental Science Division, USDOE Environmental Measurements Laboratory, New York, NY.
Measuring Environmental Radioactivity: A Brief History
Bernd Kahn and Jeffrey Lahr
Georgia Institute of Technology, Environmental Resources Center, 620 Cherry Street, 104C ESM Building, Atlanta, GA 30332-0225
A brief survey of environmental radioactivity measurements during the past 100 years is presented as a tribute to Merril Eisenbud. Naturally occurring radionuclides were identified and categorized within 30 years of the discovery of ionizing radiation from radionuclides in 1896. During the following 30 years, the few gaps in knowledge concerning these radionuclides were filled; radionuclides produced by cosmic rays were identified and measured; and artificial radionuclides produced by irradiation with energetic particles and by fission that reached the environment were monitored. Increasingly ingenious analytical methods and detectors have been applied for characterizing and measuring environmental radionuclides. Interest in such measurements has passed through several phases that are described. Efforts are now focused on radiation protection from radon accumulating in structures, radionuclides in waste from nuclear facilities, and contamination at former nuclear sites.
Key words: Radioactivity; Radiation detection; Environment; Radionuclide measurement
Address correspondence to Bernd Kahn. Tel: (404) 894-3776; Fax: (404) 894-3733.
Geochemical Investigations by the U.S. Geological Survey on Uranium Mining, Milling, and Environmental Restoration
Edward R. Landa,1 Charles A. Cravotta III,2 David L. Naftz,3 Philip L. Verplanck,4 D. Kirk Nordstrom,4 and Robert A. Zielinski5
1U.S. Geological Survey, 12201 Sunrise Valley Drive, Mail
Stop 430, Reston, VA 20192
2U.S. Geological Survey, 840 Market Street, Lemoyne, PA 17043
3U.S. Geological Survey, 2329 West Orton Circle, Salt Lake City, UT 84119
4U.S. Geological Survey, 3215 Marine Street, Boulder, CO 80303
5U.S. Geological Survey, Mail Stop 973, Denver, CO 80225
Recent research by the U.S. Geological Survey has characterized contaminant sources and identified important geochemical processes that influence transport of radionuclides from uranium mining and milling wastes. 1) Selective extraction studies indicated that alkaline earth sulfates and hydrous ferric oxides are important hosts of 226Ra in uranium mill tailings. The action of sulfate-reducing and iron-reducing bacteria on these phases was shown to enhance release of radium, and this adverse result may temper decisions to dispose of uranium mill tailings in anaerobic environments. 2) Field studies have shown that although surface-applied sewage sludge/wood chip amendments aid in revegetating pyritic spoil, the nitrogen in sludge leachate can enhance pyrite oxidation, acidification of groundwater, and the consequent mobilization of metals and radionuclides. 3) In a U.S. Environmental Protection Agency-funded study, three permeable reactive barriers consisting of phosphate-rich material, zero-valent iron, or amorphous ferric oxyhydroxide have been installed at an abandoned uranium upgrader facility near Fry Canyon, UT. Preliminary results indicate that each of the permeable reactive barriers is removing the majority of the uranium from the groundwater. 4) Studies on the geochemistry of rare earth elements as analogues for actinides such as uranium and thorium in acid mine drainage environments indicate high mobility under acid-weathering conditions but measurable attenuation associated with iron and aluminum colloid formation. Mass balances from field and laboratory studies are being used to quantify the amount of attenuation. 5) A field study in Colorado demonstrated the use of 234U/238U isotopic ratio measurements to evaluate contamination of shallow groundwater with uranium mill effluent.
Key Words: Geochemical investigations; Uranium mining waste; Environmental restoration
Address correspondence to Edward R. Landa. Tel: (703) 648-5898; Fax: (703)648-5484; E-mail: firstname.lastname@example.org
The use of trade names in this report is for identification purposes only and does not constitute endorsement by the USGS.
Thorium Isotopes in Humans, Foodstuffs, and the Environment
Isabel M. Fisenne
U.S. Department of Energy, Environmental Measurements Laboratory, 201 Varick Street, 5th Floor, New York, NY 10014-4811
Three naturally occurring thorium isotopes, 228,230,232Th, are of interest for diverse reasons. These are discussed and the exposure of humans to environmental levels of these thorium isotopes is summarized in an attempt to develop global baseline values for future modeling purposes. From this summary, limited both in quantity of measurements and geographical diversity, the following observations can be made. The few reported air concentration measurements are reasonably close to the UNSCEAR reference values of 1, 0.5, and 1 mBq m-3 of air for 228,230,232Th. Measured drinking water concentrations for all three isotopes of thorium are generally higher than the UNSCEAR reference values of 0.05 mBq L-1 for 228,232Th and 0.1 mBq L-1 for 230Th. The average global dietary intakes are 28 mBq 228Th, 8 mBq 230Th, and 5 mBq 232Th day-1, respectively. The most data for human tissues are for bone ash, which averaged 310 mBq 228Th kg-1, 115 mBq 230Th kg-1, and 75 mBq 232Th kg-1.
Key words: Thorium isotopes; Human exposure; Environmental levels
Address correspondence to Isabel M. Fisenne. Tel: (212) 620-3643; Fax: (212) 620-3600; E-mail: email@example.com
Long-Term Measurement of Indoor and Outdoor 212Pb Decay Products, With Estimates of Aerosol Particle Size
Naomi H. Harley and Passaporn Chittaporn
New York University School of Medicine, Nelson Institute of Environmental Medicine, 550 First Avenue, MSB Room C-90, New York, NY 10016
Measurements of the 220Rn (thoron) decay product, 212Pb, were made weekly in filtered air samples both indoors and outdoors in three locations. Two types of samplers were used to collect samples simultaneously, one an ultrafine particle size sampler, which was used in this study to remove the ultrafine fraction, and the other to collect the total filtered air particles. Weekly samples were collected over a 2-year period at a single family home in northern New Jersey, and in an underground basement laboratory in New York City, and 5 months of weekly data outdoors on an apartment terrace adjacent to Manhattan in urban New Jersey. These measurements are part of a larger study to measure the indoor and outdoor ultrafine particle size distribution. The measurements reported here use the naturally occurring 220Rn decay product 212Pb as an atmospheric tracer for aerosol particles. The 212Pb measurements at the single family home showed a seasonal trend of about a factor of two, both in the basement and outdoors. The highest 212Pb concentration occured in warm weather and averaged about 200 and 50 mBq m-3 in the basement and outdoors, respectively. A crude particle size estimate indicated that about 20% and 15% of the 212Pb aerosol particles in these indoor and outdoor locations, respectively, had a median diameter less than 50 nm.
Key words: Thoron; Aerosol particles; Decay product; Indoor measurements; Outdoor measurements
Address correspondence to Naomi H. Harley. Tel: (212) 263-5287; Fax: (212) 263-5287; E-mail: firstname.lastname@example.org
Concentrations of 232Th, 226Ra, and 40K in Soil Around Rocky Flats and Along Colorado's Front Range Corridor
S. E. Hulse, S. A. Ibrahim, J. M. Stone, and F. W. Whicker
Department of Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523
Concentrations of 232Th, 226Ra and 40K in soil from 42 sites around the Rocky Flats Environmental Technology Site and 20 regional locations were measured in the laboratory with gamma spectroscopy. Mean concentrations of 232Th (96 Bq kg-1) and 40K (720 Bq kg-1 for the entire 0-21 cm depth interval were nearly the same at all sample sites although there were marginal differences in surface soil (0-3 cm) at some locations. Concentrations of 226Ra exhibited the greatest variability throughout the top 21 cm of soil but, with a few exceptions, mean concentrations for the entire interval were not significantly different from the mean (63 Bq kg-1) for all locations. Rocky Flats is located along apparent regional concentration gradients that decrease from Colorado Springs north to Fort Collins, CO at a mean rate of 4 Bq kg-1 km-1for 40K and 0.4Bq kg-1 km-1 for 232Th. No evidence was found for locally increased soil concentrations of 232Th from sources at Rocky Flats, although variability of natural background may have obscured any effects from releases. There are, however, associations between soil concentrations of 232Th, 226Ra, and 40K and soil type, unconsolidated surficial deposits of alluvium and other debris, and bedrock.
Key words: Soil concentrations; Natural radionuclides; Thorium; Radium; Potassium
Address correspondence to S. E. Hulse.
Radionuclide Accumulation, Radiation Exposure, and Regeneration for Granular Activated Carbon Removing Radon From Drinking Water
C. T. Hess, G. P. Bernhardt IV, J. J Amsden, J. Ngue Mba, and R. Jones
Department of Physics and Astronomy, University of Maine, 5709 Bennett Hall, Orono, ME 04469-5709
The University of Maine has been devising procedures for dealing with
radiation accumulation and disposal problems for granular activated carbon
which were used to remove radon from drinking water. The study was done in collaboration with water utilities (Readfield and Friendship), public water supplies (Athens), private water supplies (New Gloucester, Cumberland, and Mount Desert), and in collaboration with the Maine Department of Health engineering. We measured the operating GAC filters for gamma radiation using a high-pressure ion chamber and a GM counter. Water samples were taken at the same time before and after filtration for radon analysis. GAC samples were also taken on-site and analyzed by high purity Ge detector measurements for 214Bi, 214Pb, 210Pb, 235U, 226Ra and 228Ac. We then regenerated the GAC containing the above radionuclides by washing it with hydrochloric acid, nitric acid, acetic acid, EDTA, sodium hydroxide, potassium hydroxide, and distilled water to achieve removals ranging from 30% to a factor of 3. Results indicated that several radionuclides became trapped in the charcoal, thus causing additional gamma ray exposure near the filter, but two to six times less than was predicted by the theoretical total adsorption theories. Buildup of radionuclides such as 210Pb and 226Ra was less than predicted by the theoretical total adsorption theories. Also many of the above radionuclides could be removed, thus regenerating the carbon, by washing with acids and bases.
Key words: Radionuclide accumulation; Granular activated carbon filters; Drinking water; Radon removal
Address correspondence to C. T. Hess. Tel: (207) 581-1018; Fax: (207) 581-3410, E-mail: email@example.com
Doses and Risks From Exposures to Naturally Occurring Thorium
J. R. Johnson
IDIAS, Inc., 4535 West 9th Avenue, Vancouver, B.C., Canada V6R 2E2
This article reviews environmental and occupational exposure to thorium. It summarizes exposures from current uses in industry and environmental exposure from food and air. The metabolic models recommended by the International Commission on Radiological Protection (ICRP) and their use in dosimetry calculations are described. This information is used to evaluate methods for dose calculation from exposure data. Monitoring methods required to meet the ICRP recommended levels for bioassay monitoring are given and the utility of in vivo and in vitro methods is compared. It is concluded that both are required for bioassay monitoring of 228Th, 232Th, and 230Th. Personal air samplers are a useful addition to identify the time of intake and 220Rn in breath monitoring for 232Th/228Th is recommended as a supplement to this as it can be used to estimate the total body burden.
Key words: Thorium; Environmental exposure; Occupational exposure; Monitoring methods
Address correspondence to John R. Johnson. Tel: (602) 222-1047, ext. 6610; Fax: (604) 222-7309; E-mail: firstname.lastname@example.org
An Adjoint Method of Calculation of Solar-Particle-Event Dose Rates
Keran O'Brien1 and Herbert H. Sauer2
1Department of Physics and Astronomy, Northern Arizona University,
1645 Fabulous Texan Way, P.O. Box 967, Sedona, AZ 86339-0967
2CIRES, University of Colorado, Boulder, CO 80303 and NOAA Space Environment Center, Boulder, CO 80303
High-energy solar particles, produced in association with solar flares and coronal mass ejections, occasionally bombard the earth's atmosphere, resulting in radiation intensities additional to the already-present cosmic ray dose rates. Access of these particles to the earth's vicinity during times of geomagnetic disturbance is not adequately described by using static geomagnetic field models. These solar fluxes are also often distributed nonuniformly in space, so that fluxes measured by satellites obtained at great distances from the earth and that sample large volumes of space around the earth cannot be used to predict fluxes locally at the earth's surface. We present here a method that uses the ground-level neutron monitor counting rates as adjoint sources of the flux in the atmosphere immediately above them to obtain solar particle dose rates as a function of position over the earth's surface. We have applied this approach to the large September 29-30, 1989 event (GLE 42) to obtain the magnitude and distribution of the dose rates from an atypically large event. To the best of the authors' knowledge, this is the only "first principles'' calculation of the worldwide effective dose rate distribution from a solar particle event.
Key words: Solar particles; Dose rates; Adjoint method of calculation
Address correspondence to Keran O'Brien. Tel: (520) 282-3748; Fax: (212) 672-3952; E-mail: Keran.O'Brien@nau.edu
Oak Ridge Tsca Incinerator: Health Risk or Newspaper-Induced Hysteria?
Frank L. Parker and Kenneth W. Ayers
Environmental and Water Resources, Vanderbilt University, Nashville, TN 37235
The Governor of Tennessee in 1997 constituted an independent panel to address the health concerns of the public, particularly the media, about the operation of the Toxic Substances Control Act (TSCA) Incinerator at Oak Ridge, Tennessee. The illnesses and effects claimed included "loss of sex drive, memory loss, chronic fatigue, metal poisoning, rheumatoid arthritis, lupus, ALS, MS, cardiovascular disease, respiratory problems, birth defects, immune problems and endocrine malfunctions." This is the only incinerator in the United States licensed to burn wastes regulated by TSCA and RCRA (Resource Conservation and Recovery Act) together with radioactive wastes. Despite almost 2 years of investigation by independent physicians, no causes have been pinpointed for the illnesses. The Panel found that the community was divided about almost everything except that there were sick workers and residents in the vicinity of the incinerator. The incinerator facility was operating in accordance with its permit. Therefore, the Panel recommended that the TSCA incinerator continue to be operated. The areal distribution of affected workers conforms to no pattern, including the predominant TSCA incinerator plume directions. The primary recommendation of the Panel was to provide relief to the affected workers and residents even without knowing the causes of the illnesses. Additionally, the Panel recommended that a scientifically valid epidemiological analysis should be conducted to determine whether or not the rate of the illnesses is within the normal range. The Panel recommended more basic research on why these people are sick and why some people are more susceptible to illnesses than others.
Key words: Oak Ridge TSCA incinerator; Health risks; Hazardous wastes; Epidemiological analysis
Address correspondence to Frank L. Parker. Tel: (615) 343-2371; Fax: (615) 322-3365; E-Mail: Parkerfl@vuse.vanderbilt.edu
Radioactive Fallout During Eisenbud's Career
Professor Emeritus Physiology & Biophysics and Medicine, University
of Tennessee, 894 Union Avenue, Memphis, TN 38163
In the early 1950s, during nuclear weapons testing by the United States and Soviet Union, the extent and results of radioactive fallout were being learned. Merril Eisenbud initiated monitoring of mixed fission products across the U.S., and later, around the world. By 1962 the vital importance of 131I was recognized, and Eisenbud measured 131I in milk, and in thyroids of children in New York City. He later established prophylactic measures to reduce iodine incorporation into the thyroid.
Key words: Nuclear weapons testing; Radioactive fallout; Iodine
Address correspondence to L. VanMiddlesworth, Ph.D., M.D. Tel: (901) 448-5822; Fax: (901) 448-7126; E-mail: LVANMID@physio1.utmem.edu
Status of Commercial Low-Level Radioactive Waste Disposal in the United States
Michael T. Ryan1 and Walter E. Newcomb2
1Medical University of South Carolina, Department of Health
Administration and Policy, 19 Hagood Avenue, Suite 408, P.O. Box 250807,
Charleston, SC 29425
2Chem-Nuclear Systems, LLC, 1625 Berkshire Lane, Harrisburg, PA 17111-6889
Since the passage of the Low-Level Radioactive Waste Policy Act of 1980 and Low-level Radioactive Waste Policy Amendments Act in 1985, all states have been required to arrange for disposal of commercial low-level radioactive waste (LLRW) that is generated within their borders. Three disposal sites exist today. One is in Washington State and serves the Northwest and Rocky Mountain Compacts. The second is in South Carolina and serves all states except North Carolina. Both sites operate under licensure from their Agreement State regulatory agencies. A third site in Clive, UT, operates under a Utah state license and is approved for essentially Class A waste. The nation's current disposal capacity is adequate to manage the decreasing volumes of LLRW for the next several decades. Attempts to develop new commercial LLRW sites have been made in California, Connecticut, Illinois, North Carolina, Nebraska, New Jersey, Pennsylvania, and Texas. Identification, licensing, and operation of sites for commercial LLRW facilities in each of these states have been stalled by political considerations and/or a complex and poorly defined licensing process. The nation's licensing process for such facilities lacks clarity in its technical direction, its specific requirements, and its implementation. If new facilities are to be developed, the process must be improved to assure future capacity at a reasonable price.
Key words: Low-level radioactive waste; Disposal sites; Licensing process
Address correspondence to Michael T. Ryan. Tel: (843) 792-1926; Fax: (843) 792-3327; E-mail: Ryanmt@musc.edu
Indoor and Outdoor 222Rn Measurements in Bangkok and Chiang Mai, Thailand
Passaporn Chittaporn and Naomi H. Harley
New York University School of Medicine, Nelson Institute of Environmental Medicine, 550 First Avenue, New York, NY 10016
Indoor and outdoor measurements of <+>222<+>Rn were made in two locations in Bangkok and six locations in Chiang Mai, Thailand, intermittently over a 4-year period using a passive 222Rn detector of our own design. Each detector contains triplicate CR-39 nuclear track film. 222Rn concentrations indoors and outdoors were identical, as expected in a tropical climate, where substantial outdoor to indoor air exchange rates are expected. Average outdoor concentration in Bangkok was 15 ± 1 Bq m-3, and indoors it was 14 ± 1 Bqm -3. Both indoor and outdoor measurements are thus the same and similar to outdoor measured concentrations in most countries. In Chiang Mai the outdoor concentration averaged 44 ± 1 Bq m-3, similar to the reported U.S. indoor average, while indoors averaged 39 ± 2 Bq m-3, again not statistically different. No seasonal changes were seen in Bangkok, a large urban city, while in the mountain city of Chiang Mai there was a seasonal variation of about a factor of 2, with the high concentrations occurring during the cool season. A tropical climate offers a relatively controlled constant 222Rn exposure to a population and may provide a special group for the study of health effects.
Key words: Radon; Indoor measurements; Outdoor measurements; Tropical climate
Address correspondence to Passaporn Chittaporn. E-mail: email@example.com
Inventory Estimates of 239,240Pu in Soil East of Rocky Flats, Colorado
Scott B. Webb, Shawki A. Ibrahim, and F. Ward Whicker
Colorado State University, Department of Radiological Health Sciences, Fort Collins, CO 80523
Through extensive geographic and depth-profile sampling of soils, radiochemical analysis, and statistical modeling, we estimated the total inventory of 239,240Pu released by the Rocky Flats Environmental Technology Site to the soil east of a waste storage area known as the 903 Pad. Our best estimate, which applies only to a sector located between 0.2 and 19 km from the 903 Pad and within an arc from 60 to 120 true bearing, is 53 GBq (1.4 Ci). This value is roughly a factor of two lower than several historical estimates of environmental plutonium contamination of soil in that same area. Our estimate apparently differs from previous work because it includes the effect of soil displacement by rock, which is very abundant in the study area and which contains very little plutonium. We considered most sources of error in calculating the geometric mean and standard deviation using a Monte Carlo approach. The primary source of variance in the total inventory estimation was the statistical uncertainty in the parameter estimations for the equations used to calculate the inventory. This method resulted in a total uncertainty estimate that was greater than estimates reported for previous studies.
Key words: Plutonium; Rocky Flats; Soil contamination; Environmental health risk
Address correspondence to Scott B. Webb, Carlsbad Environmental Monitoring & Research Center, New Mexico State University, 1400 University Drive, Carlsbad, NM 88220. Tel: (505) 234-5538; Fax: (505) 887-3051.
Environmental Measurements Laboratory Fifty Years Later
Mitchell D. Erickson
Environmental Measurements Laboratory, U.S. Department of Energy, 201
Varick Street, New York, NY 10014-4811
The Health and Safety Laboratory, predecessor of the Environmental Measurements Laboratory (EML), was founded by Merril Eisenbud. This article describes the evolution of the EML from its inception as a monitoring laboratory for radioactive fallout from nuclear weapons tests to the current mission covering a broad range of low-level environmental radiation and radioactivity measurements.
Key words: Environmental Measurements Laboratory; Health and Safety Laboratory; Environmental monitoring
Address correspondence to Mitchell D. Erickson. Tel: (212) 620-3616;
Fax: (212) 620-3651; E-mail: firstname.lastname@example.org