Natural radioactivity levels and associated health hazards from the terrestrial ecosystem in Rosetta branch of the River Nile, Egypt.

Twenty soil and 25 sediment samples were collected from the banks and bottom of the River Nile in the surroundings of biggest cities located close to it. Natural radioactivity concentrations of 226Ra, 232Th and 40K have been evaluated for all samples by means of γ spectrometric analysis. The radioactivity levels of soil and sediment samples fall within the internationally recommended values. Nevertheless, high natural background radiation zones are detected in the Kafr El-Zayat region due to the presence of a fertilizer factory, and in the Rosetta region due to the presence of black sand deposits. The absorbed dose rate, the γ index and excess life time cancer risk are calculated. High values for some of the radiation health parameters are detected in the Kafr El-Zayat and Rosetta regions representing a serious problem to public health because the soil and sediment are used as constructing material for buildings. Furthermore, the isotope analysis of uranium for representative collected sediment samples via α spectrometry showed average specific activities of 18.7 ± 3.6, 0.087 ± 0.0038 and 18.6 ± 3.8 Bq kg-1 for 234U, 235U and 238U, respectively. In general, these values confirm the balance in the isotopic abundance of U isotopes.

Positive Influence of 177Lu PSMA-617 Therapy on Bone Marrow Depression Caused by Metastatic Prostate Cancer.

A 75-year-old man with castrate-resistant prostate cancer and increasing prostate-specific antigen (PSA) level developed severe bone marrow depression during Ra radionuclide therapy. Because of this, he was treated with Lu-PSMA in compassionate use for this not-yet-approved therapy. At the beginning of Lu-PSMA therapy, repeated blood transfusions (BT) were necessary. Six months after the last BT, after 3 cycles of Lu-PSMA, his blood count stabilized. He required no further BTs and his PSA level remained lowered.

Dosimetric characterization of two radium sources for retrospective dosimetry studies.

PURPOSE: During the first part of the 20th century, (226)Ra was the most used radionuclide for brachytherapy. Retrospective accurate dosimetry, coupled with patient follow up, is important for advancing knowledge on long-term radiation effects. The purpose of this work was to dosimetrically characterize two (226)Ra sources, commonly used in Sweden during the first half of the 20th century, for retrospective dose-effect studies. METHODS: An 8 mg (226)Ra tube and a 10 mg (226)Ra needle, used at Radiumhemmet (Karolinska University Hospital, Stockholm, Sweden), from 1925 to the 1960s, were modeled in two independent Monte Carlo (MC) radiation transport codes: geant4 and mcnp5. Absorbed dose and collision kerma around the two sources were obtained, from which the TG-43 parameters were derived for the secular equilibrium state. Furthermore, results from this dosimetric formalism were compared with results from a MC simulation with a superficial mould constituted by five needles inside a glass casing, placed over a water phantom, trying to mimic a typical clinical setup. Calculated absorbed doses using the TG-43 formalism were also compared with previously reported measurements and calculations based on the Sievert integral. Finally, the dose rate at large distances from a (226)Ra point-like-source placed in the center of 1 m radius water sphere was calculated with geant4. RESULTS: TG-43 parameters [including gL(r), F(r, θ), Λ, and sK] have been uploaded in spreadsheets as additional material, and the fitting parameters of a mathematical curve that provides the dose rate between 10 and 60 cm from the source have been provided. Results from TG-43 formalism are consistent within the treatment volume with those of a MC simulation of a typical clinical scenario. Comparisons with reported measurements made with thermoluminescent dosimeters show differences up to 13% along the transverse axis of the radium needle. It has been estimated that the uncertainty associated to the absorbed dose within the treatment volume is 10%-15%, whereas uncertainty of absorbed dose to distant organs is roughly 20%-25%. CONCLUSIONS: The results provided here facilitate retrospective dosimetry studies of (226)Ra using modern treatment planning systems, which may be used to improve knowledge on long term radiation effects. It is surely important for the epidemiologic studies to be aware of the estimated uncertainty provided here before extracting their conclusions.

Radiation safety considerations for the use of ²²³RaCl2 DE in men with castration-resistant prostate cancer.

The majority of patients with late stage castration-resistant prostate cancer (CRPC) develop bone metastases that often result in significant bone pain. Therapeutic palliation strategies can delay or prevent skeletal complications and may prolong survival. An alpha-particle based therapy, radium-223 dichloride (²²³RaCl2), has been developed that delivers highly localized effects in target areas and likely reduces toxicity to adjacent healthy tissue, particularly bone marrow. Radiation safety aspects were evaluated for a single comprehensive cancer center clinical phase 1, open-label, single ascending-dose study for three cohorts at 50, 100, or 200 kBq kg⁻¹ body weight. Ten patients received administrations, and six patients completed the study with 1 y follow-up. Dose rates from patients administered ²²³Ra dichloride were typically less than 2 µSv h⁻¹ MBq⁻¹ on contact and averaged 0.02 µSv h⁻¹ MBq⁻¹ at 1 m immediately following administration. Removal was primarily by fecal excretion, and whole body effective half-lives were highly dependent upon fecal compartment transfer, ranging from 2.5-11.4 d. Radium-223 is safe and straightforward to administer using conventional nuclear medicine equipment. For this clinical study, few radiation protection limitations were recommended post-therapy based on facility evaluations. Specific precautions are dependent on local regulatory authority guidance. Subsequent studies have demonstrated significantly improved overall survival and very low toxicity, suggesting that ²²³Ra may provide a new standard of care for patients with CRPC and bone metastases.

Natural radioactivity in drinking underground waters in Upper Silesia and solid wastes produced during treatment.

Content of (226)Ra, (228)Ra and uranium isotopes in waters from subsurface aquifers was studied. The sampling points were chosen for having the elevated natural content of iron and manganese. Measurements of radium were made by LSC, while uranium was measured by alpha spectrometry. Waste sludge was measured by gamma spectrometry and three-stage BCR sequential extraction was performed. Radon activity concentration in the air at water treatment plants was determined and dose adsorbed by staff was calculated.

Radon and the risk of cancer mortality--internal Poisson models for the German uranium miners cohort.

Uranium mining occurred between 1946 and 1990 at the former Wismut mining company in East Germany. 58,987 male former employees form the largest single uranium miners cohort, which has been followed up for causes of mortality occurring from the beginning of 1946 to the end of 2003. The purpose of this paper is to present the radon exposure related cancer mortality risk based on 20,920 deaths, 2 million person-years, and 6,373 cancers. The latter include 3,016 lung cancers and 3,053 extrapulmonary solid cancers. Internal Poisson regression was used to estimate the excess relative risk (ERR) per unit of cumulative radon exposure in Working Level Months (WLM) for all major sites and for the follow-up period from 1946 to 2003. The simple cohort ERR WLM for lung cancer is 0.20% [95% confidence interval (CI): 0.17%; 0.22%]. The ERR model for lung cancer is linear in radon exposure with exponential effect modifiers that depend on age at median exposure, time since median exposure, and radon exposure-rate. In this model the central estimate of ERR WLM is 1.06% (95% CI: 0.69%; 1.42%) for an age at median exposure of 33 y, a time since median exposure of 11 y, and an exposure-rate of 2.7 WL. This central ERR decreases by 5% for each unit exposure-rate increase. The ERR decreases by 32% with each decade increase in age at median exposure and also decreases by 54% with each decade increase in time since median exposure. The ERR WLM for all extrapulmonary solid cancers combined without effect modification is 0.014% (95% CI: 0.006%; 0.023%). The ERR model for extrapulmonary solid cancer is linear in radon exposure with an exponential effect modifier which depends on age-attained. In this model the central estimate of ERR WLM is 0.040% (95% CI: -0.001%; 0.082%) for an age-attained of 44. The ERR decreases by 37% with each decade increase in age-attained. The highest ERR WLM, after lung, is observed for cancers of the pharynx (0.16%), tongue/mouth (0.045%), and liver (0.04%).

Escaping radioactivity from coal-fired power plants (CPPs) due to coal burning and the associated hazards: a review.

Coal, like most materials found in nature, contains trace quantities of the naturally occurring primordial radionuclides, i.e. of (40)K and of (238)U, (232)Th and their decay products. Therefore, the combustion of coal results in the released into the environment of some natural radioactivity (1.48 TBq y(-1)), the major part of which (99%) escapes as very fine particles, while the rest in fly ash. The activity concentrations of natural radionuclides measured in coals originated from coal mines in Greece varied from 117 to 435 Bq kg(-1) for (238)U, from 44 to 255 Bq kg(-1) for (226)Ra, from 59 to 205 Bq kg(-1) for (210)Pb, from 9 to 41 Bq kg(-1) for (228)Ra ((232)Th) and from 59 to 227 Bq kg(-1) for (40)K. Fly ash escapes from the stacks of coal-fired power plants in a percentage of 3-1% of the total fly ash, in the better case. The natural radionuclide concentrations measured in fly ash produced and retained or escaped from coal-fired power plants in Greece varied from 263 to 950 Bq kg(-1) for (238)U, from 142 to 605 Bq kg(-1) for (226)Ra, from 133 to 428 Bq kg(-1) for (210)Pb, from 27 to 68 Bq kg(-1) for (228)Ra ((232)Th) and from 204 to 382 Bq kg(-1) for (40)K. About 5% of the total ash produced in the coal-fired power plants is used as substitute of cement in concrete for the construction of dwellings, and may affect indoor radiation doses from external irradiation and the inhalation of radon decay products (internal irradiation) is the most significant. The resulting normalized collective effective doses were 6 and 0.5man-Sv(GWa)(-1) for typical old and modern coal-fired power plants, respectively.

Estimation of ionizing radiation impact on natural Vicia cracca populations inhabiting areas contaminated with uranium mill tailings and radium production wastes.

Industrial areas in proximity to the Vodny settlement in the Komi Republic, Russia, have been contaminated by uranium mill tailings and radium production wastes. These areas, exhibiting high activity concentrations of naturally occurring radionuclides in soils, constitute a field laboratory where the effects of combined chronic exposures to alpha-, beta- and gamma-emitting radionuclides on natural plant populations can be studied. The aim of the present work was to determine dose-effect relationships and the range of doses that cause biological effects in natural Vicia cracca L. populations inhabiting the study area. The studied plant species is native to the area and is found ubiquitously. Soil and vegetation samples were taken at a reference location and six contaminated sites characterized by distinct floodplain depositional units with different enhanced levels of naturally occurring radionuclides. A large fraction of the dose at the study sites (including the reference location) was attributable to internal irradiation and (226)Ra was found to be an important contributor to this component of dose. The relationship between the frequency of chromosome aberrations in seedlings' root tip cells and the absorbed dose was found to be quadratic. An exponential model provided the best result in describing the empirical dependence between the absorbed dose and both the germination capacity of seeds and the survival rate of sprouts of V. cracca. For V. cracca plants inhabiting areas contaminated with uranium mill tailings and radium production wastes, a weighted absorbed dose of 0.2 Gy (weighting factor for alpha particles=5) during the vegetation period could be considered to be a level below which no increase in genetic variability and decrease in reproductive capacity might be observed above background.

Evaluation of DNA damage in the root cells of Allium cepa seeds growing in soil of high background radiation areas of Ramsar-Iran.

Plants are unique in their ability to serve as in situ monitors for environmental genotoxins. We have used the alkaline comet assay for detecting induced DNA damage in Allium cepa to estimate the impact of high levels of natural radiation in the soils of inhabited zones of Ramsar. The average specific activity of natural radionuclides measured in the soil samples for 226Ra was 12,766 Bq kg(-1) whereas in the control soils was in the range of 34-60 Bq kg(-1). A positive strong significant correlation of the DNA damage in nuclei of the root cells of A. cepa seeds germinated in the soil of high background radiation areas with 226Ra specific activity of the soil samples was observed. The results showed high genotoxicity of radioactively contaminated soils. Also the linear increase in the DNA damage indicates that activation of repair enzymes is not triggered by exposure to radiation in HBRA.

Osteonecrosis of the jaw and bisphosphonates: a comparison with white phosphorus, radium, and osteopetrosis.

INTRODUCTION: Recent reports of bisphosphonate-associated jaw osteonecrosis are reminiscent of earlier incidents in which a comparable syndrome was caused by occupational exposure to white phosphorus or radium. Osteonecrosis of the jaw is also caused by an inherited disease: osteopetrosis. This review analyzes the biomedical and social aspects of these four situations associated with jaw osteonecrosis. RESULTS: Clinical evidence is contradictory but suggests aminobisphosphonates cause rare cases of jaw necrosis. In addition to jaw problems, generalized skeletal defects characterize osteopetrosis and exposure to phosphorus or radium and there is evidence of decreased bone resorption in these conditions and with bisphosphonate therapy. CONCLUSION: Bisphosphonate-induced jaw necrosis appears to be an on-target toxicity as the same mechanism, inhibition bone resorption, probably underlies both the therapeutic and adverse effects. Since bisphosphonates are retained for long periods by bone the theoretical potential for skeletal toxicity is increased by using higher doses of potent aminobisphosphonates administered less frequently.

Well water radioactivity and risk of cancers of the urinary organs.

Water from bedrock frequently contains higher concentrations of natural radionuclides than water from other sources. Bladder and kidneys receive a radiation dose when radioactive isotopes are excreted into urine. The subjects for this case-cohort study were selected from all drilled wells users in Finland. The study comprised 61 bladder cancer and 51 kidney cancer cases diagnosed between 1981 and 1995, as well as a random sample of 274 reference persons, stratified by age and sex. The median activity concentrations of radon in drilled wells used by bladder and kidney cancer cases and the reference cohort were 170, 140, and 130 Bq/L, respectively. The radium concentration was 0.01 Bq/L for all groups and the uranium concentrations were 0.08, 0.07, and 0.06 Bq/L, respectively. The bladder cancer risks associated with radon, radium, and uranium activity concentrations in drinking water were 1.02 (0.68-1.54) per log(100 Bq of radon/L), 0.73 (0.21-2.50) per log(0.1 Bq of radium/L), and 0.77 (0.32-1.89) per log(1 Bq of uranium/L). The corresponding figures for kidney cancer were 0.81 (0.47-1.37), 0.12 (0.01-1.10), and 0.92 (0.36-2.35), respectively. In conclusion, even though ingested radionuclides from drilled wells are a source of radiation exposure, they are not associated with a substantially increased risk of bladder or kidney cancers in concentrations occurring in drilled wells.

The effect of exposure to employees from mining and milling operations in a uranium mine on lead isotopes--a pilot study.

Potential exposure during mining and milling of uranium ore has resulted in the industry being highly regulated. Exposure can arise from inhalation of the daughter product radioactive gas radon (222Rn), inhalation of radioactive dust particles from mining and milling, direct irradiation from outside the body, and ingestion of radionuclides (e.g. uranium or radium) in food or water. Making use of the highly unusual lead isotopic signature for uranium ores (high 206Pb/204Pb from the high uranium content, low 208Pb/204Pb from the low Th/U ratio), we undertook a pilot study of nine male mine employees and three controls from the Ranger uranium mine in the Northern Territory Australia to determine if it was feasible to use lead isotopes in blood to identify exposure to uranium-derived materials. The lead isotopic data for the mine employees and controls plot in two distinct fields which are consistent with predicted isotopic patterns. Assuming retention of 10% of the ingested lead, then the increases seen in 206Pb represent intakes of between 0.9 and 15 mg, integrated over the years of exposure. The small amount of lead does not affect blood lead concentrations, but appears to be sufficient to be detectable with sensitive isotopic methods. Further studies, including those on urine, should be undertaken to confirm the veracity of the lead isotope method in monitoring exposure of uranium industry employees.

Radon and other natural radionuclides in drinking water and risk of stomach cancer: a case-cohort study in Finland.

Very high concentrations of naturally occurring radionuclides are encountered in Finnish groundwaters and wells. Radon ingested through drinking water can cause considerable radiation to the stomach. We assessed the effect of natural uranium and other radionuclides in drinking water on the risk of stomach cancer. Subjects (n = 144,627) in the base cohort had lived outside the municipal tap water system during 1967-1980. A subcohort of 4,590 subjects was formed for use as a reference group by random sampling of the base cohort, with stratification by age and sex. Within the subcohort, 371 subjects had used drinking water from drilled wells prior to 1981. Stomach cancer cases within the subcohort were identified through a cancer registry, and cases using water from drilled wells were selected. Activity concentrations of radon, radium-226 and natural uranium in the drinking water were analyzed using radiochemical and alpha spectrometric methods. The median activity concentration of radon in well water was 130 Bq/l for both the 88 stomach cancer cases and the 274 subjects in the subcohort. Median radium concentrations were 0.007 Bq/l for cases and 0.010 Bq/l for the subcohort, with a median uranium concentration of 0.07 Bq/l for both groups. Risk of stomach cancer was not associated with exposure to radon or other radionuclides. The hazard ratio of stomach cancer was 0.68 for radon (95% CI 0.29-1.59 at 100 Bq/l water), 0.69 per Bq/1 for radium-226 (95% CI 0.33-1.47) and 0.76 per Bq/1 for uranium (95% CI 0.48-1.21). Our results do not indicate an increased risk of stomach cancer from ingestion of radon or other natural radionuclides through drinking water at these exposure levels.

Daily intakes of 238U, 234U, 232Th, 230Th, 228Th and 226Ra in the adult population of central Poland.

Activity concentration of the uranium and thorium series radionuclides was determined in foodstuffs and drinking water in central Poland. Annual and daily intake for the adult population was estimated from the concentrations determined and average annual consumption of food and water. The daily intakes (in mBq) were 22.1 (238U), 26.5 (234U), 2.38 (232Th), 4.06 (230Th), 11.2 (228Th) and 42.2 (226Ra). The intake of uranium isotopes occurred mainly with water; the main intake of thorium isotopes was with animal products, vegetables, cereals and potatoes, whereas 226Ra entered mainly with animal products, cereals and vegetables. From the intake and dose coefficients, the annual effective doses for the ingested radionuclides were calculated. The annual effective dose was 5.95 microSv, of which 72.4% originated from 226Ra.

224Ra-induced osteopenia in male CBA mice.

Six groups of young adult, male mice were injected with six dose levels of the bone-seeking, alpha-emitting radionuclide 224Ra (half-life 3.6 days); a seventh group was injected with saline alone. The administered doses were relatively low, ranging from 2 to 64 kBq per animal. The mice were maintained under standard laboratory conditions until they either died or became moribund, when they were killed. The mean ages at death of the experimental groups were not significantly different from the normal control group. Individual bones--the mandible, parietal, nasal, and bulla--were isolated and standard linear measurements and dry weights were obtained. In all measurements considered, the highest two administered amounts (32 and 64 kBq) caused a significant reduction relative to controls. Low power microscopy of the mandible revealed osteonecrosis in the high dose groups. This is similar to the condition of "radium jaw" which has been described as a late effect of either accidental ingestion or therapeutic administration of 226Ra (half-life 1,620 years) in man; the other bones did not show obvious osteonecrosis. This work emphasizes the long-term osteopenic effects of low-dose radium, even in the short-lived species 224Ra. It also provides a method of quantifying the osteopenic effect of bone-seeking radionuclides.

Cancer risk from the lifetime intake of Ra and U isotopes.

From extensive human data on the induction of skeletal cancers (bone sarcomas and carcinomas of the head sinuses) by 226Ra, 228Ra and 224Ra, the cumulative lifetime risk to 1 million people, each ingesting 5 pCi of a Ra isotope per day, was calculated to be nine bone sarcomas plus 12 head carcinomas for 226Ra, 22 bone sarcomas for 228Ra, and 1.6 bone sarcomas for 224Ra. Assuming that the risk per rad of average skeletal dose is equal for 226Ra and the U isotopes with half-lives exceeding 1000 yr and that the equilibrium skeletal content is 25 times the daily ingestion of 226Ra, but 11 times the daily ingestion of long-lived U, the cumulative life-span risk to 1 million persons, each ingesting 5 pCi per day of 233U, 234U, 235U, 236U or 238U, is estimated to be about 1.5 bone sarcomas. The U risk is not well established and additional research is needed on the metabolism of U in humans and its carcinogenicity in laboratory animals. These estimates assume linear dose responses. However, if incidence varies with the square of dose, virtually no induced cancers would be expected from these levels of radioactivity.

Radiation-induced myelomatosis.

It is well known that radiation can cause myeloid leukemia. However, no excess of chronic lymphocytic leukemia has been observed. Myelomatosis, like chronic lymphocytic leukemia, is a tumor of B lymphocytes. To determine whether this disease has a radiogenic origin, we surveyed all cohorts of persons exposed to radiation for which data on cancer-related mortality are available. An excess of myeloma was found in most cohorts. However, a striking deficit was found in two groups irradiated intensely for uterine neoplasms (three cases observed, 10.71 expected; P = 0.012). All other groups combined had a highly significant excess (50 observed, 22.21 expected; P = 2 X 10(-7)). The largest relative risk appeared among persons receiving internal doses of alpha-particles (14 observed, 3.24 expected; P = 2 X 10(-5)), but a significant excess (13 observed, 6.33 expected; P = 0.026) was also found in patients receiving only therapeutic or diagnostic gamma-rays or x-rays. Most cases occurred 15 to 25 years after exposure.

Occupational exposure to radiation as a cancer hazard.

There is much experimental data which indicates that ionizing radiation is a very potent carcinogenic agent. Most types of carcinoma can be produced by radiation. Carcinoma is apparently induced through a single or a series of mutations in somatic cells. Radiologists have excess leukemia and other malignancy from external x-ray; uranium and other miners have excess lung cancer from internal alpha radiation; luminous dial painters have excess osteogenic sarcomas; and uranium mill workers appear to have excess lymphomas. A large number of persons are now exposed occupationally to radiation from nuclear reactors, and from various uses of radioisotopes. For the induction of most types of cancers from radiation it appears that the risk is between 0.5 and 2 cancers per rem per million person years. Epidemiological techniques are essential in determining risks of this low magnitude. Other agents may inhibit or enhance the carcinogenicity of radiation.