Acute Radiation Syndrome (ARS): A Fact Sheet for the Public
Radiation sickness, known as acute radiation syndrome (ARS), is a serious illness that occurs when the entire body (or most of it) receives a high dose of radiation, usually over a short period of time. Many survivors of the Hiroshima and Nagasaki atomic bombs in the 1940s and many of the firefighters who first responded after the Chernobyl Nuclear Power Plant accident in 1986 became ill with ARS.
People exposed to radiation will get ARS only if:
The radiation dose was high (doses from medical procedures such as chest X-rays are too low to cause ARS; however, doses from radiation therapy to treat cancer may be high enough to cause some ARS symptoms),
The radiation was penetrating (that is, able to reach internal organs),
The person’s entire body, or most of it, received the dose, and
The radiation was received in a short time, usually within minutes.
The first symptoms of ARS typically are nausea, vomiting, and diarrhea. These symptoms will start within minutes to days after the exposure, will last for minutes up to several days, and may come and go. Then the person usually looks and feels healthy for a short time, after which he or she will become sick again with loss of appetite, fatigue, fever, nausea, vomiting, diarrhea, and possibly even seizures and coma. This seriously ill stage may last from a few hours up to several months.
People with ARS typically also have some skin damage. This damage can start to show within a few hours after exposure and can include swelling, itching, and redness of the skin (like a bad sunburn). There also can be hair loss. As with the other symptoms, the skin may heal for a short time, followed by the return of swelling, itching, and redness days or weeks later. Complete healing of the skin may take from several weeks up to a few years depending on the radiation dose the person’s skin received.
The chance of survival for people with ARS decreases with increasing radiation dose. Most people who do not recover from ARS will die within several months of exposure. The cause of death in most cases is the destruction of the person’s bone marrow, which results in infections and internal bleeding. For the survivors, the recovery process may last from several weeks up to 2 years.
If a radiation emergency occurs that exposes people to high doses of radiation in a short period of time, they should immediately seek medical care from their doctor or local hospital.
More Information
For more information about radiation and emergency response, see the Centers for Disease Control and Prevention’s Emergency Preparedness and Response website or contact the following organizations:
The CDC Public Response Source at 1-888-246-2675
Conference of Radiation Control Program Directors (CRCPD) at 502-227-4543
U.S. Environmental Protection Agency (EPA)
Nuclear Regulatory Commission (NRC) at 301-415-8200
Federal Emergency Management Agency (FEMA) at 202-646-4600
Radiation Emergency Assistance Center/Training Site (REAC/TS) at 865-576-3131
U.S. National Response Team (NRT)
U.S. Department of Energy (DOE) at 1-800-dial-DOE
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http://toxnet.nlm.nih.gov/cgi-bin/sis/search/r?dbs+hsdb:@term+@na+@rel+cesium,+radioactive
Human Health Effects:
Toxicity Summary:
TOXICITY SUMMARY: The element cesium exists in several forms known as isotopes. In nature, cesium exists only as a non-radioactive (or stable) isotope known as cesium-133 (Cs-133); however, there exist several cesium isotopes that are radioactive. The radioactive isotopes of cesium are formed during nuclear fission, in commercial applications such as the generation of electricity at nuclear power plants. The most important cesium isotopes in terms of their potential effects on human health are cesium-134 (Cs-134) and cesium-137 (Cs-137). In this summary, the most pertinent information on the radiation toxicity of Cs-134 and Cs-137 are presented. Both Cs-137 and Cs-134 emit beta radiation and gamma radiation. Beta radiation travels short distances and can penetrate the skin and superficial body tissues while gamma radiation can travel great distances and penetrate the entire body. The radiation dose from these radionuclides can be classified as either external (if the radiation source is outside the body) or internal (if the radiation source is inside the body). Beta radiation emitted outside the body is normally of little health concern unless the radioactive material contacts the skin. Skin contact can allow the beta radiation to pass through the epidermis to live dermal tissue where it becomes a major contributor to the radiation dose to the skin. Beta and gamma radiation may induce tissue damage and disruption of cellular function. The half-lives of Cs-134 and Cs-137 are approximately 2 years and 30 years, respectively. Because of the continual emission of radiation, people could be exposed to radiation from Cs-137 or Cs-134 released to the environment. High levels of Cs-134 and Cs-137 have been released to the environment from nuclear weapons testing and incidents such as the 1986 accident at the Chernobyl nuclear reactor in Ukraine. In these cases, cesium was one of many radionuclides present in the release. It is, thus, not possible to ascribe any of the observed health effects to radioactive cesium specifically. There are, however, documented reports of health effects in humans exposed to radioactive cesium. These reports arise from the accidental exposure of civilians to Cs-137 sources in Goiania, Brazil, in 1987 and Tammiku, Estonia, in 1994 and from the exposure of military personnel to Cs-137 during 1996 and 1997 in Lilo, Republic of Georgia. External and internal exposures of humans to radiocesium have resulted in a spectrum of adverse health effects that range from nausea to death. In 1987, approximately 250 persons, including children, were exposed externally and internally to radiation from a scavenged medical source with an activity of 50.9 TBq (1,375 Ci) 137-CsCl. Some of the exposed individuals showed signs of acute radiation syndrome, such as nausea, vomiting, and diarrhea. A large number of the individuals with acute radiation syndrome developed bone marrow failure and 4 of these died. Dermal injuries observed among the exposed individuals ranged from radiation dermatitis to severe radiation injuries leading to an amputation. Ocular and reproductive effects were also reported. Two incidents of external exposure to radiation from Cs-137 have demonstrated that serious adverse effects may also be expected when individuals are exposed only externally to high levels of radiation from Cs-137. In 1997 it was discovered that military recruits had been accidentally exposed to several sealed Cs-137 radioactive sources at a training facility in Lilo, Republic of Georgia. Nausea, weakness, headaches, and loss of appetite were the most commonly reported symptoms among the exposed recruits. Vomiting was reported by three of the patients, two of whom received the highest estimated doses. The exposures of the recruits occurred over several months. Although accurate information on the duration of the exposure was not available, doses were estimated by scoring unstable chromosome aberrations in peripheral blood lymphocytes and by electron spin resonance dosimetry of teeth of the exposed individuals. The estimated mean doses ranged from 0.2 to 5.9 Gy (The radiological event at Lilo. International Atomic Energy Agency (2000). Vienna). In 1994, several individuals (aged 13 to 78) were exposed to a sealed Cs-137 source stolen from a waste repository in Tammiku, Estonia. The observed health effects in the exposed individuals ranged from a relatively mild case of radiation sickness to death. Solid state dosimetry techniques were applied for reconstruction of the doses of several individuals exposed in the house where the stolen Cs-137 source was kept. The estimated whole body radiation doses ranged from 0.1 Gy to 4 Gy. The individual with the highest estimated whole body dose also had an estimated localized radiation exposure to the thigh of 1,830 Gy. The latter individual died 12 days after the initial exposure event. The survivors showed dermal effects and effects in blood. A 13-year old male was the most exposed among the survivors (estimated whole-body dose of 1.5-5.5 Gy). He suffered severe and prolonged bone marrow aplasia and radiation burns. (The Radiological Accident in Tammiku (1998). The International Atomic Energy Agency, Vienna. 4 November 1998). (SRC)
Evidence for Carcinogenicity:
There is inadequate evidence in humans for the carcinogenicity of cesium-137. /Cesium/
There is sufficient evidence in experimental animals for the carcinogenicity of mixed beta-particle emitters (iodine-131, cesium-137, cerium-144 and radium-228). /Iodine, Cesium, Cerium, Radium/
Evaluation. There is sufficient evidence in humans for the carcinogenicity of X-radiation and gamma-radiation. There is sufficient evidence in experimental animals for the carcinogenicity of X-radiation and gamma-radiation. Overall evaluation. X-radiation and gamma-radiation are carcinogenic to humans (Group 1).
Human Toxicity Excerpts:
/SIGNS AND SYMPTOMS/ /ACUTE RADIATION SYNDROME/ Fifty persons involved in the cesium-137 accident in Goiania showed symptoms of whole-body and local acute irradiation and also external or internal contamination mainly due to ingestion or absorption of cesium-137. Fourteen of the 50 developed severe bone marrow depression characterized by neutropenia and thrombocytopenia. Eight of these 14 received GM-CSF intravenously. None were submitted to bone marrow transplantation. Four of the 14 died due to hemorrhage and infection. For those with significant internal contamination evaluated by in-vitro and in-vivo assays, Prussian Blue was administered with doses ranging from 1.5 to 10 g/day. Besides Prussian Blue, other measures were taken to increase decorporation of cesium-137, including administration of diuretics, water overload, and ergometric exercises. From 50 to 100 persons are being followed in a medical protocol. /Cesium-137/
/SIGNS AND SYMPTOMS/ /ACUTE RADIATION SYNDROME/ Approximately 250 individuals were exposed externally to an open 50.9 TBq (1,375 Ci) 137-cesium chloride radioactive source in Goiania, Brazil, in 1987. Many of these individuals also experienced oral and dermal exposure. The estimated absorbed doses ranged from 1 to 7 Gy (100 to 700 rad). The exposed individuals showed signs and symptoms of acute radiation syndrome including vomiting, diarrhea, and nausea, as well as skin lesions from radiation burns, orofacial lesions, ocular injury, hematological effects (bone marrow aplasia, leukopenia, thrombocytopenia, lymphopenia, neutropenia), mild elevations of some liver enzymes, and reduced sperm counts. Twenty individuals developed the acute radiation syndrome, 14 (70%) of whom developed bone marrow failure after having received whole-body radiation doses ranging from 1 to 7.0 Gy (100 to 700 rad). Four (29%) of these 14 individuals died. The adverse effects were the result of beta and gamma radiation, not cesium per se. /Cesium-137 chloride/
/CASE REPORTS/ /LIVER/ Mild elevations of aminotransferases (ALT/AST) were seen in a few patients hospitalized following radiation exposure to an opened cesium-137 chloride radioactive source in Goiania, Brazil, in 1987. /Cesium-137 chloride/
/CASE REPORTS/ /ACUTE RADIATION SYNDROME/ On 13 September 1987, a radiation accident occurred in the city of Goiania in Central Brazil. Approximately 250 people were exposed to a cesium-137 source from an abandoned radiotherapy unit. At least 14 patients showed some degree of bone marrow depression, and eight developed the classical signs and symptoms of acute radiation syndrome (ARS). Twenty-eight people presented local radiation injuries ranging from first to third degree, and 104 individuals showed evidence of internal contamination. This paper describes the circumstances of the event, the first-aid measures taken, the criteria adopted for triage of the exposed population, and the radiation protection procedures used during the clinical management of the irradiated individuals. /Cesium-137/
/CASE REPORTS/ /SKIN/ A case of child abuse involving industrial radiography sources has been reported ... . A petroleum engineer had possession of at least a 37GBq (1Ci) cesium-137 source used for oil and gas well logging. The dose rate at contact for such a source is approximately 5 Gy/min. One of the engineer's sons was subjected to various occasions in which "shiny silver pellets" were in the earpieces of headphones that he was told to wear, in a pillow he was told to use, and in a sock he found on his bed. It was also assumed that while under sedation, he was exposed at other times of which he was unaware. He was first seen by a family physician for what appeared to be bruises and reddish-brown blisters. These were assumed to be infections, but over succeeding weeks and months, new lesions appeared on the medial aspects of the thighs, right ankle, right hand, and left side of his forehead. ... Over the next 6 months, persistent, ulcerating lesions of the right thigh kept the child out of school. ... A plastic surgeon recognized the lesions as radiation necrosis. Both testes had been effectively destroyed, and the boy was functionally castrated. /Cesium-137/
/CASE REPORTS/ /ACUTE RADIATION SYNDROME/ In Tammiku, Estonia, in 1994, a cesium-137 source (a few terabecquerels) thought to have been part of an irradiator was disposed of as scrap metal. It was recovered and stored in a source store with limited security. The store was broken into and the source removed. Six people, exposed to varying degrees up to 4 Gy whole body, developed a variety of lesions. One localized exposure was up to 1,800 Gy and the person died. /Cesium-137/
/CASE REPORTS/ /SKIN/ Eleven frontier guards were exposed to one or more sources of cesium-137 with activities up to 150 GBq at the Lilo Training Center near Tbilisi, Georgia. The incident occurred over a period spanning 1996 and 1997. The sources were intended for training civil defense specialists or for calibration. Some of the sources had been removed from their containers, either still fixed in the source holder or separate from it. Information on the irradiation is incomplete, but it appears that at least one source was kept in the pocket of a coat. Each of the guards suffered from one or more acute localized irradiation lesions of varying seriousness; several suffered from nausea and vomiting. /Cesium-137/
/CASE REPORTS/ /ACUTE RADIATION SYNDROME/ In an accident involving the stealing and breaching of a radiotherapy source in Goiania, Brazil, 39 individuals had a high level of cesium-137 internal contamination. Prussian Blue was used, in doses that varied from 3-10 g/day for adults, to enhance the elimination of cesium-137 from the body. The total internal committed doses and the effect of Prussian Blue treatment for 15 contaminated adults involved in this accident have been evaluated in this paper. Prussian Blue caused dose reductions in the range of 51-84%, with an average of 71%. This reduction was shown to be independent of the dosage of Prussian Blue. ...
/CASE REPORTS/ /ACUTE RADIATION SYNDROME/ In September 1987, the Goiania radiological accident involving a source of cesium-137 culminated in about 140 victims who presented internal and/or external contamination and/or external exposure to radiation and/or radiation burns. Internal contamination was verified through analysis of urine and fecal samples. Internal contamination was also evaluated by measurements performed at the whole-body counter installed in Goiania in November 1987. To enhance the decorporation of cesium-137, patients were treated with the following: 1) Prussian Blue, oral administration, in 46 patients; 2) diuretics, oral administration, in 17 patients; 3) induced perspiration, increasing cesium-137 elimination. These procedures were done under rigorous clinical evaluation and considering the data from assay of excreta and data obtained from the whole-body counter. The doses of Prussian Blue exceeded about 6.5 times the dose previously indicated in the literature. It was the first time diuretics were used in humans to treat cesium-137 internal contamination. The results of these procedures are discussed. /Cesium-137/
/CASE REPORTS/ /REPRODUCTIVE SYSTEM/ Spermatozoa were reduced or absent in the semen of nine males examined approximately 1 month following presumed acute radiation doses on the order of several hundred rad from an opened cesium-137 chloride radioactive source in Goiania, Brazil, in 1987. These individuals may have experienced mixed external, dermal, and oral exposure. /Cesium-137 chloride/
/CASE REPORTS/ /EYE/ Among 20 patients hospitalized following mixed external and internal exposure to an opened cesium-137 chloride radioactive source in Goiania, Brazil, in 1987, a few patients complained of lacrimation, hyperemia and edema of the conjunctiva, and ocular pain. A few cases of protracted reduction in visual capacity were also reported, among which retinal injury was documented. In these cases, there was no change in lens transparency. These effects were due to the radiation, not to cesium per se. /Cesium-137 chloride /
/EPIDEMIOLOGY STUDIES/ More than 25,000 residents were exposed to external gamma radiation as well as internally from fission products (primarily from cesium-137, strontium-90, ruthenium-106, and zirconium-95) released into the Techa river from the nearby Mayak plutonium production facility, predominately in the early 1950s. Studies have been conducted of cancer mortality in residents and their offspring, as well as pregnancy outcomes. Initial dose estimates were based on average doses reconstructed for settlements. Efforts are ongoing to estimate individual doses for members of this resident cohort. To date, there is no evidence of a decrease in birth rate or fertility in the exposed population and no increased incidence of spontaneous abortions or stillbirths. There is some evidence of a statistically significant increase in total cancer mortality. Current estimates of the excess absolute risk (EAR) of leukemia in this cohort is 0.85 per 10,000 person-year Gy (95% confidence interval 0.2, 1.5), and for solid tumors the relative risk estimate is 0.65 per Gy (95% confidence interval -0.3, 1.0). Median dose estimates for soft tissue in this cohort are 7 mSv (maximum 456 mSv), and for bone marrow are 253 mSv (maximum 2021 mSv). Estimates of the relative risk for cancer of the esophagus, stomach and lung are similar to those reported for atomic bomb survivors. There is no evidence of an increase in cancer mortality in the offspring of exposed residents. There has also been one study of persons living in the town of Ozyorsk exposed to fallout from the nearby Mayak nuclear facility. An excess of thyroid cancer 3-4 times expected relative to rates for all of Russia has been observed. The excess is somewhat lower (1.5-2-fold higher) based on a comparison with Chelyabinsk Oblast rates. No estimates of radiation dose were included in this study. /Cesium-137, strontium-90, ruthenium-106, and zirconium-95 contamination/
/EPIDEMIOLOGY STUDIES/ A few studies have investigated adult resident populations living in highly contaminated areas. ...The incidence of leukemia and lymphoma in the general population of the Bryansk region of Russia for the period 1979-1993 /was investigated/ using an ad hoc registry of hematological diseases established after the Chernobyl accident. The incidence rates in the 6 most contaminated districts (more than 37 kBq/sq m of cesium-137 deposition density) did not exceed the rates in the rest of the region or in Bryansk city, where the highest rates were observed. Comparisons of crude incidence rates before and after the accident (1979-1985 and 1986-1993) showed a significant increase in the incidence of all leukemia and non-Hodgkin lymphoma, but this was mainly due to increases in the older age groups in rural areas. The incidence of childhood leukemia and non-Hodgkin lymphoma was not significantly different in the 6 most contaminated areas from the incidence in the rest of the region. Similarly, ... no evidence of an increase in leukemia rates in the most contaminated areas of the Kaluga district of the Russian Federation /was found/ after the Chernobyl accident. In Ukraine, ...incidence rates for leukemia and lymphoma in the most highly contaminated areas of the Zhytomir and Kiev districts /were examined/ before and after the Chernobyl accident. Total incidence in adults increased from 5.1 per 100,000 during 1980-1985 to 11 per 100,000 person-years during 1992-1996 but there was no excess in contaminated areas of the regions. Similarly, ...the incidence of leukemia and lymphoma /was investigated/ in the three most contaminated regions of Ukraine. There was a steady increase in leukemia and lymphoma rates for both men and women between 1980 and 1993, but there was no evidence of a more pronounced increase after the accident. /Cesium-137 fallout/
/EPIDEMIOLOGY STUDIES/ ...Reports have focused on changes in childhood leukemia rates before and after the accident in individual European countries and elsewhere. Overall, there was little evidence for an increase in rates of childhood leukemia in Ukraine, Belarus, Russia, Finland, Sweden, Greece, or a number of other countries from Central, Eastern and Southern Europe after the Chernobyl accident. Furthermore, there was no association between the extent of contamination /(primarily cesium-137)/ and the increase in risk in these countries. However, one Swedish study, reported a nonstatistically significant increase of /acute lymphoblastic leukemia/ (ALL) after the accident in children younger than five years old (OR=1.5, 95% confidence interval 0.8, 2.6). A small study in northern Turkey showed that in one pediatric cancer treatment center, more patients with ALL were seen after the accident than before, but no incidence rates were reported. There has been only one analytic (case-control) study of childhood leukemia reported based on cases identified among residents of the Rivno and Zhytomir oblasts in Ukraine. Cases were under age 20 at the time of the accident and were diagnosed between 1987 and 1997. Data were collected on 272 cases, however, the analysis was based on only 98 cases that were independently verified and interviewed. Controls were randomly selected fro the same oblasts, excluding the raion of residence of the case, and matched according to age at the time of the accident, sex, and type of settlement. The mean estimated dose to the bone marrow among study subjects was 4.5 mSv and the maximum was 101 mSv. the study found a statistically significant increased risk of acute leukemia among males with cumulative doses above 10 mSv and diagnosed form 1993-1997. A similar association was found for acute myeloid leukemia diagnosed in the period 1987-1992. Theses results should be interpreted cautiously, however, as they are based on approximately only one-third of the cases and a lesser proportion of controls, and it is not clear whether cases and controls were selected for dose estimation in an unbiased manner. /Cesium-137 fallout/
/EPIDEMIOLOGY STUDIES/ Several studies have investigated the risk of leukemia in children exposed to Chernobyl fallout /(primarily cesium-137)/ while in utero. All are ecologic in design, and results are inconsistent. The initial study compared rates for temporal cohorts born during "exposed" and "unexposed" periods in Greece and found a 2.6-fold increase in leukemia risk and elevated rates for those born in regions with higher levels of radioactive fallout. However, the numbers of cases in each exposure group were small and the results could not be duplicated when a similar approach comparing areas with the same categories of contamination (<6 kBq/sq m, 6-10 kBq/sq m, >10 kBq/sq m) was applied to the analysis of data from the German Childhood Cancer Registry. In a study in Belarus, where levels of contamination are higher by a factor of ten or more, the results were similar to the Greed study but the trend was weaker. Nevertheless, although the findings are based on small number and are not statistically significant, the highest annual incidence rate was in 1987, the year after the accident, and the largest rate ratio (RR=1.51, 95% confidence interval 0.63, 3.61) was in the two most contaminated regions: Gomel and Mogilev. A more recent small study ... compared leukemia incidence during 1986 to 1996 among children born in 1986 and thus exposed in utero in Zhitomir, a contaminated region with children born in Poltava, a relatively uncontaminated region. The reported risk ratios based on cumulative incidence show significant increases for all leukemia (relative risk (RR)=2.7, 95% confidence interval 1.9, 3.8) and for the subtype of acute lymphoblastic leukemia (RR=3.4, 95% confidence interval 1.1, 10.4). The ongoing European Childhood Leukemia-Lymphoma Incidence Study (ECLIS) has evaluated the risk of leukemia by age using data from population-based cancer registries in Europe (including Belarus and Ukraine). Focusing on the risk of leukemia by age of diagnosis in 6 month intervals in relation to the estimated doses from the Chernobyl fallout received in utero, preliminary results suggest a small increase in risk in infant leukemia and leukemia diagnosed between 24-29 months. /Cesium-137 fallout/
/EPIDEMIOLOGY STUDIES/ Fall-out from weapons testing in the 1950s and from the Chernobyl accident resulted in the ingestion of cesium-137 by Lapps who breed reindeer in the northern parts of the Nordic countries and the Russian Federation. In addition, small amounts of americium and plutonium were ingested by Lapps from contaminated reindeer. A cohort of 2034 Lapps who bred reindeer in Sweden or who were members of the households of breeders was assembled in 1960 and followed through mortality registries from 1961 through 1985. The rate of mortality from all causes was similar to that of the entire Swedish population: 428 deaths occurred, and the SMR was 0.95. A significantly lower mortality rate than expected was observed for all cancers (SMR, 0.70), and significantly decreased risks were found for cancers of the colon, respiratory organs, female breast, male genital organs and kidneys and for malignant lymphomas. The stomach was the only site for which a significantly increased risk for cancer was found (SIR, 2.25; 95% CI, 1.46-3.32) when compared with national rates. /Cesium-137 fallout/
/BIOMONITORING/ /GENOTOXICITY/ The results of... three post-Chernobyl studies (two in Belarus and one in Ukraine) and for the one conducted on the populations in the vicinity of the nuclear test site in Semipalatinsk (Kazakhstan) provide evidence that mutations at minisatellite loci can be induced by radiation in human germ cells. The dose-response relationships, however, remain uncertain because of considerable difficulties in the estimation of parental gonadal doses. For example, in the first Belarus study the level of surface contamination by cesium-137 was used as a broad dose measure, and the children of parents inhabiting heavily contaminate areas (>250 kBq/sq m) were found to have twice the frequency of mutations compared to those of parents from less contaminated areas (<250 kBq/sq m). In the second Belarus study (with more exposed families and more loci sampled), based on estimates of individual doses, two groups were defined <20 mSv and >20 mSv. The mutation frequency in the children from the latter group was 1.35 times that in the former and that from both groups was about 2-fold higher than in the unexposed U.K. controls. In the Ukraine study, a 1.6-fold increase in mutation rate in the exposed fathers but not in exposed mothers (both relative to unexposed controls) was found, but again, the dose-response relationship is uncertain. The authors noted that the dose from external chronic irradiation and internal exposures together were of the order of approx. 100 mSv (excluding short-lived isotopes). In the Semipalatinsk study, again, there was a 1.8-fold increase in the first generation progeny of parents receiving relatively high doses of radiation (cited as >1.0 Sv, but could have been lower or higher). In this study, through the use of three-generation families, the authors obtained evidence for a decline in mutation frequency as population doses decreased. /Cesium-137 fallout/
/BIOMONITORING/ /GENOTOXICITY/ Following the Goiania radiation accident, lymphocytes from 110 exposed or potentially exposed individuals were analyzed for the frequencies of chromosomal aberrations (dicentrics and centric rings) to estimate absorbed radiation dose. Dose estimates for 21 subjects exceeded 1.0 Gy, and for eight subjects they exceeded 4.0 Gy. Four of the subjects died. After the emergency period, a cytogenetic follow-up of 10 of the highest exposed patients was started. The results suggest that the average disappearance half-time of lymphocytes containing dicentric and centric rings was 130 days, which is shorter than the usually accepted value of 3 yr reported in the literature. /Cesium-137 chloride/
/BIOMONITORING/ /GENOTOXICITY/ The current study comprises the analysis of mutations in 10 individuals accidentally exposed to cesium-137 during the 1987 radiological accident in Goiania, Brazil. Their exposures were among the highest experienced, ranging from 1 to 7 Gy. Peripheral T-lymphocyte samples were obtained 3.3 years after the original exposure and mutation was studied at the hprt locus using the 6-thioguanine-resistance selection assay. The mutational spectrum for the exposed population is comprised of 90 independent mutants. Based on T-cell receptor analysis, only 5% (5/95) were clonally related. Mutants were initially studied using RT-PCR and directly sequenced using an automated laser fluorescent DNA sequencer. Mutants that repeatedly failed to produce cDNAs were studied using a multiplex PCR assay with genomic DNA. Missense mutations were the most frequent event recovered, comprising 40% (23/57) of the spectral sample. An excess of events involving A:T base pairs was observed, exhibiting a significant difference (chi square = 12.7, P = 0.0004) when compared to the spontaneous spectrum. This finding may reflect the effect of ionizing radiation-induced damage, suggesting a potential similarity to radiation effects in prokaryotes. At the genomic level, 36.7% (33/90) of the mutants exhibited gross structural alterations, as detected by multiplex PCR. Deletion events were over-represented in our spectral sample, displaying a twofold increase when compared to the frequency observed in the spontaneous mutation database. /Cesium-137 chloride/
/BIOMONITORING/ /GENOTOXICITY/ Five years after the initial exposure to radioactive fallout from the Chernobyl accident of 1986, slightly greater frequencies of chromosomal aberrations were observed in peripheral blood lymphocytes of three groups of Byelorussian children (41 total) living in areas with ground contamination from cesium-137 fallout than in those of an Italian control group of 10 children. /Cesium-137 fallout/
/BIOMONITORING/ /GENOTOXICITY/ Results of multiyear cytogenetic study of children and teenagers living in areas, radioactive by contaminated after Chernobyl accident, were adduced. Mean density of cesium-137 contamination in two compared living areas were 111 and 200 kBq/sq m and mean external doses accumulated for 1986-2001 were 6.7 and 11.4 mGy correspondingly. Averaged thyroid doses received by subjects of all age groups in the second area were approximately 1.5 times higher than in the first area; in the youngest group (0-1 year) the doses were 114.3 and 174.3 mGy. During 17 years cytogenetic investigation approximately from 30% to 60% of examined persons were observed the increased level of chromosome aberrations in lymphocytes of peripheral blood. Average frequency of unstable aberrations (acentrics, dicentrics and centric rings) constituted about 0.4 per 100 cells (0.22 per 100 cells in controls) during all period of observation. Level of marker aberrations (dicentrics and centric rings) was increased almost all times of study and varied within 0.04-0.19 per 100 cell (0.03 in control group). The parallel investigation of frequency of stable aberrations by FISH method showed up their level about 3 times exceeding observed dicentrics level. Comparably higher indexes of cytogenetic disturbances were revealed in group exposed in utero during period of accident. /Cesium-137 fallout/
/BIOMONITORING/ /GENOTOXICITY/ Chromosome analysis of peripheral lymphocytes from two Norwegian populations (44 reindeer herding South samis from Roros and Snasa, 12 sheep farmers from Valdres) exposed to fallout from the Chernobyl accident were made. The doses from cesium through the years 1987-1991 were calculated based on whole-body measurements of cesium-134 and cesium-137 giving a total cumulative mean internal dose of 5.54 mSv for the total group of 56 persons. Chromosome aberrations were within the normal range when compared with historical controls with the exception of dicentrics (0.3% per cell, which is a 10-fold increase) and rings (0.07% per cell). A dose-dependent increase in dicentrics and rings based on cesium exposure was not observed.
/BIOMONITORING/ /GENOTOXICITY/ Fluorescence in situ hybridization (FISH) is a powerful method largely used for detecting chromosomal rearrangements, translocations in particular, which are important biomarkers for dose assessment in case of human exposure to ionizing radiation. To test the possibility of using the translocation analysis by FISH-painting method in retrospective dose assessment, /the authors/ carried out in vitro experiments in irradiated human lymphocytes, in parallel with the analysis of translocations in lymphocytes from 10 individuals, who were exposed to cesium-137 in the Goiania (Brazil) accident (samples collected 10 years after exposure). The in vitro dose-response curve for the genomic translocation frequencies (FGs) fits a linear quadratic model, according to the equation: Y=0.0243X(2)+0.0556X. The FG values were also calculated for the individuals exposed to cesium-137, ranging from 0.58 to 5.91 per 100 cells, and the doses were estimated and compared with the results obtained by dicentric analysis soon after the accident, taking the opportunity to test the validity of translocation analysis in retrospective biodosimetry. A tentative of retrospective dosimetry was performed, indicating that the method is feasible only for low level exposure (below 0.5 Gy), while for higher doses there is a need to apply appropriate correction factors, which take into consideration mainly the persistence of chromosomal translocations along with time, and the influence of endogenous and exogenous factors determining the inter-individual variability in the cellular responses to radiation.
/OTHER TOXICITY INFORMATION/ /SKIN/ The external dose from cesium radionuclides arises primarily from the penetrating gamma rays that travel great distances in air. Beta radiation emitted outside the body is normally of little health concern unless the radioactive material contacts the skin. Skin contact can allow the beta radiation to pass through the epidermis to live dermal tissue where it becomes a major contributor to a radiocesium-generated radiation dose to the skin. At very high doses, the beta and gamma radiation can cause such adverse effects as erythema, ulceration, or even tissue necrosis. /Cesium radionuclides/
/OTHER TOXICITY INFORMATION/ /ENDOCRINE SYSTEM/ ...Relatively little has been published regarding thyroid outcomes other than thyroid cancer, although one study has reported an elevated risk of benign thyroid tumors. There have been reports of increases in autoimmune disease and antithyroid antibodies following childhood exposure to Chernobyl. However, a study by the Sasakawa Foundation which screened 114,000 children found no association between a surrogate for thyroid dose (cesium-137) and thyroid antibodies, hypothyroidism, hyperthyroidism, or goiter. /Cesium-137/
Medical Surveillance:
Bioassay Method: The presence of cesium-137 is detected by gamma spectroscopy using the 0.661-MeV photon of barium-137m, which is the short half-life (T1/2 = 2.5 min) progeny that exists in secular equilibrium with cesium-137. Gamma spectroscopy can be either for in vivo measurements or for excreta analysis. In vivo whole body counting is the preferred method for cesium-137 bioassay, due to its simplicity. Urine sample gamma spectroscopy can also be highly effective if in vivo measurements cannot be readily obtained. Fecal sampling is not normally recommended due to the high absorption (theoretically, 100%) in the GI tract. (An exception might occur if a person was being treated with Prussian blue, whereby fecal results would aid in determining efficacy of the treatment.)
Annual in vivo measurements are recommended for periodic retrospective bioassay monitoring of workers potentially exposed to mixtures of radionuclides containing radiocesium... . If radiocesium is detected through a routine measurement, then follow-up measurements to confirm the initial indication should generally be performed. ... Follow-up measurements should be performed as promptly as practical following an indication of an intake in order to facilitate any health physics investigation associated with the potential exposures. However, because of the high sensitivity of the in vivo measurement, verification measurements for cesium are not appreciably affected by delays of a few days to a month in obtaining them. Follow-up in vivo measurements using high-resolution germanium detectors are preferred for identifying other radionuclides possibly associated with the exposure, to discriminate against interference from radon progeny, and because the germanium detectors provide a more precise and accurate measurement. In addition to follow-up in vivo measurements, special bioassay should be considered for other significant nuclides (e.g., strontium-90 or plutonium urinalysis, plutonium fecal analysis), if cesium-137 is a mixture indicator nuclide.
Urinalysis gamma spectrometry can provide excellent bioassay monitoring sensitivity. This sensitivity makes offsite urine sample collection a viable alternative for follow-up measurement of former workers who left the area without obtaining a termination whole body count.
Cesium has been found to be more dispersible than strontium, and therefore in most intake situations involving cesium-137 and strontium-90, cesium-137 will likely constitute the major component of intake. In cases where it is suspected that strontium-90 or other radionuclides may be present along with cesium-137 but no radionuclide ratio information exists, it is prudent to consider additional bioassay appropriate for the other radionuclides of concern.
Populations at Special Risk:
Dose rate, i.e., the time over which a radiation dose is delivered, may influence risk in a variety of ways. In experimental animals, the risk per unit dose is usually greater at higher dose rates, for the same cumulative dose of low-LET radiation.
Probable Routes of Human Exposure:
Exposure to radioactive cesium is more important from a health perspective than exposure to stable cesium(1). Current exposure of the general US population to cesium-134 and cesium-137 is expected to be low since atmospheric testing nuclear weapons has been discontinued for many years and Chernobyl-related fallout was low in the US(1).
Body Burden:
Concns of cesium-137 in human milk samples from several US cities from 1956 to 1961 were <20 pCi/L(1). The overall cesium-137 concn in milk taken 7 days postpartum from 37 mothers in two Italian hospitals were 5.8 to 115 pCi/L(1). In a study of females from northern Sweden, cesium-136 was detected in breast milk from 8 out of 12 mothers at concns of 7.3 to 178.4 pCi/kg(2). The infants of these mothers who were breast-fed had whole-body levels of cesium-137 in the range 45.9 to 675.7 pCi/kg(2).
In Finland, the mean body burdens of cesium-137 for adults were as follows (year, concn): Helsinki (1987, 649 pCi/kg; 1994, 181 pCi/kg); Vitasaari (1987, 3,514 pCi/kg; 1994, 514 pCi/kg); Ammans (1987, 2,892 pCi/kg; 1994, 811 pCi/kg)(1). The mean monthly levels of cesium-137 in human muscle tissue in Graz, Austria were reported as 1,519 (July 1986 to June 1987), 1,049 (July 1987 to June 1988), 340.5 (July 1988 to June 1989), and 202.7 pCi/kg (July 1989 to June 1990), with a max value of 9,584 pCi/kg observed in an individual during September 1986(2). The monthly averages for cesium-134 were about half of those reported for cesium-137. By comparison, the max concn of cesium-137 in muscle tissue from Harwell, England in 1959 was reported as 224 pCi/kg, the mean concn in muscle tissue from Massachusetts during January 1961 to June 1962 was 100 pCi/kg, and the mean concn in human muscle tissue obtained from Japan during April to December 1963 was reported as 119 pCi/kg(2). The mean concn of cesium-137 in the urinary excretion of Italians in northern Italy were 7.3 and 6.2 pCi/day in 1995 and 1996, respectively(3). These values were about two orders of magnitude less than values reported in 1987. The mean concn of cesium-137 in brain, heart, liver, gonads, muscle, bone, and teeth were 0.440, 1.860, 0.490, 2.440, 0.017, 0.106, and 0.23 pCi/g, respectively, in cadavers from adults which were over 34 years of age at time of death in Poland during 1975(4).
Average Daily Intake:
The avg daily intake of cesium-137 and cesium-134 was estimated for adult males residing in the Ukraine in 1994, based upon total diet samples(1). The mean intake of cesium-137 was estimated as 109 pCi/day and the mean intake of cesium-134 was estimated as 8.1 pCi/day(1). Based on dietary patterns and the concn of radiocesium in food sources, the total dietary intakes of cesium-134 and cesium-137 for typical adults residing in Croatia for the month of May 1986 were estimated as 2.8X10+4 and 5.9X10+4 pCi, respectively(2). Based on dietary patterns and the concn of radiocesium in food sources, the total dietary intakes of cesium-134 and cesium-137 for children (10 yrs old) residing in Croatia for May-June 1986 were estimated as 43,000 and 190,000 pCi, respectively(2). For infants (1 yr old), it was estimated that the total intakes of cesium-134 and cesium-137 were 46,000 and 170,000 pCi, respectively(2). The total intakes of cesium-134 and cesium-137 for adults during this same time period were estimated as 40,000 and 84,000 pCi, respectively(2). The higher intakes of cesium-134 and cesium-137 for infants and children were traced to a much greater consumption of contaminated milk(2).
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