The paper is an analytical overview of the main results presented at the 3^rd Dosimetry Workshop in Hiroshima(9-11 of March 2005), where different aspects of the dose reconstruction around the Semipalatinsk nuclear test site(SNTS) were discussed and summarized.
The results of the international intercomparison of the retrospective luminescence dosimetry(RLD) method for Dolon' village(Kazakhstan) were presented at the Workshop and good concurrence between dose estimations by different laboratories from 6 countries (Japan, Russia, USA, Germany, Finland and UK) was pointed out. The accumulated dose values in brick for a common depth of 10mm depth obtained independently by all participating laboratories were in good agreement for all four brick samples from Dolon' village, Kazakhstan, with the average value of the local gamma dose due to fallout (near the sampling locations) being about 220mGy(background dose has been subtracted).
Furthermore, using a conversion factor of about 2 to obtain the free-in-air dose, a value of local dose ~440mGy is obtained, which supports the results of external dose calculations for Dolon': recently published soil contamination data, archive information and new models were used for refining dose calculations and the external dose in air for Dolon village was estimated to be about 500mGy.
The results of electron spin resonance(ESR) dosimetry with tooth enamel have demonstrated the notable progress in application of ESR dosimetry to the problems of dose reconstruction around the Semipalatinsk nuclear test site. At the present moment, dose estimates by the ESR method have become more consistent with calculated values and with retrospective luminescence dosimetry data, but differences between ESR dose estimates and RLD/calculation data were noted. For example mean ESR dose for eligible tooth samples from Dolon' village was estimated to be about 140mGy(above background dose), which is less than dose values obtained by RLD and calculations. A possible explanation of the differences between ESR and RLD/calculations doses is the following: for interpretation of ESR data the "shielding and behaviour" factors for investigated persons should be taken into account. The "upper level" of the combination of "shielding and behaviour" factors of dose reduction for inhabitants of Dolon' village of about 0.28 was obtained by comparing the individual ESR tooth enamel dose estimates with the calculated mean dose for this settlement.
The biological dosimetry data related to the settlements near SNTS were presented at the Workshop. A higher incidence of unstable chromosome aberrations, micronucleus in lymphocytes, nuclear abnormalities of thyroid follicular cells, T-cell receptor mutations in peripheral blood were found for exposed areas (Dolon', Sarjal) in comparison with unexposed ones(Kokpekty). The significant greater frequency of stable translocations (results of analyses of chromosome aberrations in lymphocytes by the FISH technique) was demonstrated for Dolon' village in comparison with Chekoman(unexposed village). The elevated level of stable translocations in Dolon' corresponds to a dose of about 180mSv, which is close to the results of ESR dosimetry for this village. The importance of investigating specific morphological types of thyroid nodules for thyroid dosimetry studies was pointed out.
In general the 3^rd Dosimetry Workshop has demonstrated remarkable progress in developing an international level of common approaches for retrospective dose estimations around the SNTS and in understanding the tasks for the future joint work in this direction.
In the framework of a special session the problems of developing a database and registry in order to support epidemiological studies around SNTS were discussed. The results of investigation of psychological consequences of nuclear tests, which are expressed in the form of verbal behaviour, were presented at this session as well.

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There are still many differences in dose estimates depending on the applied methods of retrospective dosimetry in the areas, which were affected by nuclear tests at the Semipalatinsk nuclear test site (SNTS). In order to provide more correct estimation of radiation doses to population in proximity to the SNTS an International Intercomparison of Retrospective Luminescnence Dosimetry (RLD) method had been proposed. It was suggested there be a comparison of the dose estimates for the brick samples from the buildings in the settlement, suffered following nuclear tests at the SNTS. With this purpose, during the September-October 2002 field mission, the team of specialists from Kazakhstan and Japan had collected four whole bricks for RLD International Intercomparison. Three buildings were selected as sampling locations in Dolon' village (Kazakhstan). The slices from these bricks were distributed between six laboratories in Finland, Germany, Japan, Russia, UK and USA for independent estimations by the RLD method of the accumulated dose of external irradiation.
The descriptions of sampling, locations, data on geographical coordinates, dates of building construction, mode of cutting of samples for distribution, labeling, condition of transportation, order of the distribution of samples and information concerning ¹³⁷Cs and ^239+240Pu soil contamination density in the village and near sampling locations are presented in the paper.

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We have applied the thermoluminescence dosimetry technique to measure the total external dose from all the nuclear explosions in a few locations near the Semipalatinsk nuclear test site in Kazakhstan. The technique was optimized at our laboratory by fundamental study of the method of thermoluminescence dosimetry. The measured values of each sample at 10 mm depth were 248 ± 102 mGy (KSD-1), 30 ± 76 mGy (2(1-3)), 222 ± 63 mGy (2(3-2)), 217 ± 55 mGy (2(4-1)). The results are part of an international intercomparison exercise using bricks collected from the areas surrounding the Semipalatinsk nuclear test site.

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Thermoluminescence (TL) and optically stimulated luminescence (OSL) techniques were applied to quartz grains extracted from various depths in bricks taken from buildings in the village of Dolon', Kazakhstan, to determine the cumulative absorbed dose, D_T. The measurements were performed in four laboratories (EU supported Measurement Group). The results obtained using TL and OSL are compared and discussed with reference to known sources of experimental uncertainty and relevant luminescence characteristics that may affect the evaluation of the absorbed dose. The external nature of the irradiation due to gamma rays from artificial radionuclides is verified by the measurement of depth-dose profiles, and these are compared with those obtained in previous studies for bricks from the same region. To produce these profiles, the cumulative dose due to natural background radiation, D_BG, was assessed, particularly based on the concentrations of radionuclides of lithogenic origin within the bricks and the surrounding environment. The consistency of these estimates of D_BG was assessed using depth-dose data and absorbed dose determinations for bricks collected from shielded locations. The values of cumulative absorbed dose since the onset of fallout, D_X, were calculated as the difference between the values of total cumulative dose in bricks since its manufacture, D_T, and values of D_BG. Furthermore, estimations of the cumulative absorbed doses in air in the reference location near the sampled buildings, _RLD_X, were obtained using corresponding conversion factors, C_RL, estimated on the basis of previous work. In addition to results for samples distributed for the International Intercomparison, reference is made to relevant results from samples that were collected in 1999 from Dolon' village and studied as part of EU-supported research.

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The method of electron paramagnetic resonance (EPR) spectroscopy for tooth enamel is applied to individual radiation dose determination to residents of two villages (Dolon and Mostik) in the vicinity of the Semipalatinsk nuclear test site in Kazakhstan. These villages are located near the central axis of the radioactive fallout trace of the most contaminating surface nuclear test conducted in 1949. It is found that excess doses obtained by subtraction of natural background dose from dose absorbed in enamel range up to 440 mGy to residents of Dolon, whose enamel was formed before 1949, and do not exceed 120 mGy to younger residents. To residents of Mostik, excess doses do not exceed 100 mGy regardless of age except for one resident with an extremely high dose of 1.25 Gy. These results are in agreement with the pattern of radioactive contamination of the territory after the nuclear test of 1949 except one case of extremely high dose, which should be additionally investigated.

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The method of electron paramagnetic resonance (EPR) dosimetry was applied to the enamel of the teeth extracted from the residents of the Dolon and Bodene settlements of the Beskaragay district, which is the area adjacent to the radioactive fallout of the most contaminating nuclear test of 1949. The individual accidental radiation doses due to the fallout were obtained from the amplitude of the radiation induced EPR signal from the CO_2- radical using the calibration method, after determining the parameters of EPR measurements to obtain the best reproducibility of the signal intensities. It was shown that after subtracting the natural background dose from the total absorbed dose obtained by EPR the residents of Dolon and Bodene received accidental radiation doses up to 356 mGy with an average value of 74.1 ± 45.5 mGy before 1949 while the younger population received up to about 100 mGy with an average value of 11.5 ± 37.7 mGy.

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Between 1949 and 1989 the Semipalatinsk nuclear test site (SNTS), an area of 19,000 square km in northeastern Kazakhstan, was the location of over 400 nuclear test explosions with a total explosive energy of 6.6 Mt TNT (trinitrotoluene or trotyl) equivalent. It is estimated that the bulk of the radiation exposure to the population resulted from three tests, conducted in 1949, 1951, and 1953 although estimations of radiation doses received by the local population have varied significantly. Analysis of the published ESR dose reconstruction results for residents of the villages near the SNTS show that they do not correlate well with other methods of dose assessment (e.g. model dose calculation and thermo luminescence dosimetry (TLD) in bricks). The most significant difference in dose estimations was found for the population of Dolon, which was exposed as result of the first Soviet nuclear test in 1949. Published results of ESR measurements in tooth enamel are considerably lower than other dose estimations. Detailed analysis of these results is provided and a possible explanation for this discrepancy and ways to eliminate it are suggested.

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General aspects of applying the method of retrospective dose estimation by electron paramagnetic resonance spectroscopy of human tooth enamel (EPR dosimetry) to the population residing in the vicinity of the Semipalatinsk nuclear test site are analyzed and summarized. The analysis is based on the results obtained during 20 years of investigations conducted in the Medical Radiological Research Center regarding the development and practical application of this method for wide-scale dosimetrical investigation of populations exposed to radiation after the Chernobyl accident and other radiation accidents.

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Investigations were conducted into chemical treatments suitable for concentrating enamel from cow teeth. Cow teeth could be used as alternative to human teeth for retrospective dosimetry when human teeth are not available. It is essential to remove dentin from tooth enamel for low dose radiation dosimetry in order to avoid interference to the ESR signal from organic radicals. Increasing the period of chemical treatment with KOH and NaOH reduced the signal intensity of the organic radicals. The sensitivity of the dosimetric signal from inorganic radicals increased slightly with length of treatment with NaOH, which is consistent with removal of dentin, and rose to a maximum of 20% after 5h with KOH (40°C).

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A comparative analysis of two groups of highly irradiated victims was carried out in order to evaluate the suitability of two assays for retrospective dose assessment: late translocations and electron spin resonance (ESR) dosimetry. The first group comprised 24 subjects who exhibited acute radiation syndrome (ARS) due to overexposure as a result of nuclear submarine accidents during the period 1961-1985. Their grades of ARS and individual doses were ascertained by Navy physicians who carried out primary examinations and treatment of the exposed seamen. Cytogenetic analyses were made 16-40 y after their accidents. During medical treatment seven tooth samples were collected for ESR analysis from this group. The second group consisted of ten highly irradiated men from the Chernobyl accident. Comparison was made between estimates of their average whole-body penetrating radiation doses derived from several biological parameters. In three cases ESR measurements on tooth enamel from this group were also made. Retrospective dosimetry using FISH translocations was attempted 10-13 y later. Yields of late translocations were in good agreement with initially estimated doses and with doses obtained by ESR spectroscopy analysis of tooth enamel long after exposure. It was concluded that both persisting stable translocations and ESR spectroscopy signals are suitable with similar efficiencies for retrospective biodosimetry after acute whole-body exposure.

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The influence of X-ray baggage scanning on electron spin resonance (ESR) dosimetry studies around the Semipalatinsk Nuclear Test Site (SNTS) has been examined at Incheon Airport in Korea, which is a transfer point of the routes from Kazakhstan to Japan. Utilized dosimeters are Japanese human tooth enamel for ESR and glass dosimeters.
The difference between the estimated doses with the X-ray scan and those without it is below the evaluation errors for both ESR and the glass dosimeters. For glass dosimeters, the dose from the X-ray scan is estimated to be lower than the detection limit for the utilized glass dosimeters of ten μGy. This supports the absence of significant difference for the ESR results, which have an error in the order of ten mGy. Since ESR dosimetry for SNTS usually has similar errors, the dose by the X-ray scan in this study is concluded to be negligible in ESR dosimetry using tooth enamel from residents near SNTS.

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To evaluate the present levels of ^239,240Pu and U in residents living near the Semipalatinsk nuclear test site, more than 70 bone samples were obtained at autopsy. The subjects ranged in age from 30 to 86 years (mean 59.3±12.9). Most of the samples consisted of victims who died of various diseases. Plutonium and U were radiochemically separated and determined by α-ray spectrometry. The mean concentrations of ^239,240Pu and ²³⁸U observed were 0.050±0.041 mBq/g-ash (vertebrae 71, long-bones 18) and 0.28±0.13 mBq/g-ash (22.8±10.6 μg U/kg-ash) (vertebrae 58, long bones 16), respectively. The present ^239,240Pu levels were within the range found for human bone samples from other countries due solely to global fallout in the early 1980s. The average U concentration was close to the estimate (mean 22.5 μg U/kg-ash) for the UK, and about 10 times higher than those estimated for residents in New York City and Japan. By assuming that the average concentration of ^239,240Pu in bone samples is the value at 45 years after instantaneous inhalation in 1955, the initial total intake and the effective dose for 45 years were estimated as 10 Bq and 0.2 mSv, respectively. The annual intake of total U (^234,235,238U) and its effective dose for 60 years were estimated as 30 Bq for adult and 0.1 mSv, respectively, for chronic ingestion.

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The Semipalatinsk Test Site (STS) in Kazakhstan was one of the major sites used by the former USSR for testing nuclear weapons for more than 40 years. Since the early 1990s, agricultural activities have been re-established there by neighbouring collective and private farms. Therefore, it has become important to evaluate the radiological situation and the current and future risk to people living on and using the contaminated area. During the last eight years, GSF has participated in many international projects performed on the STS to evaluate the radiological situation. A large number of soil, vegetation and food samples has been collected and analysed. Internal dose is one of the main components of the total dose when deriving risk factors for a population living within the test site. Internal doses, based on food monitoring and whole body measurements, were calculated for adults and were in the range of 13-500 μSv/y due to radiocaesium and radiostrontium.

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The present situation of radioactive contamination at the village of Dolon and nearby villages such as Mostik, Cheremushka and Budene was investigated to serve as an aid to resolve dose discrepancy between model calculations and TL measurements made for external gamma-ray dose in air in Dolon. The paper was focused on the reevaluation of the accumulated levels and distribution of long-lived radionuclides ¹³⁷Cs and Pu isotopes in soil using long core samples up to a depth of 30 and 100 cm.
The inventories of ¹³⁷Cs and ^239,240Pu found were in the wide range of 140-10,310 and 140-14,320 Bq/m², respectively. Most of the Pu in soil was tightly incorporated into various sizes of fused particles. Both ¹³⁷Cs and ^239,240Pu in soil were accumulated in the smaller soil size fraction of <125 μm, and the presence of hot particles, probably due to Pu, was clearly observed by star-like patterns from α-tracks. The obtained data will be helpful for evaluating the current and future radiation risks to the people living around there.

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The Imaging Plate (IP) technique which uses the Monte Carlo code, MCNP, to convert IP response to ⁹⁰Sr concentration with varied thickness of the standard source has been proposed in this study. In order to verify the validity of simulation calculation in the proposed method, the radial distribution of IP signal has been compared between calculation and experiment. The result is, they are in good agreement.
The proposed method has been applied to a cow tooth from the territory contaminated by radioactivity after the accident in the Mayak facility in the South Ural, Russia. Two samples have been prepared from the tooth, i.e., a thin sample of 1.2 ± 0.2 mm in thickness and a thick sample which is a half of the tooth. The IP response has been evaluated for the thick sample using experimentally made standard sources, and multiplied by a modification factor to decide that for the thin sample. The modification factor has been determined with MCNP to be 0.83 ± 0.08 for a thickness of 1.2 ± 0.2 mm. Using these values, ⁹⁰Sr concentration has been estimated to be 0.11 Bq/g for the thin sample and 0.12 Bq/g for the thick sample, hence they are in good agreement.

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Dolon village, located about 60 km from the border of the Semipalatinsk Nuclear Test Site, is known to be heavily contaminated by local fallout from the first USSR atomic bomb test in 1949. External radiation in Dolon was evaluated based on recent ¹³⁷Cs data in soil and calculation of temporal change in the fission product composition. After fitting a log-normal distribution to the soil data, a ¹³⁷Cs deposition of 32 kBq m^-2, which corresponds to the 90th-percentile of the distribution, was tentatively chosen as a value to evaluate the radiation situation in 1949. Our calculation indicated that more than 95% of the cumulative dose for 50 y had been delivered within 1 y after the deposition. The resulting cumulative dose for 1 y after the deposition, normalized to the initial contamination containing 1 kBq m^-2 of ¹³⁷Cs, was 15.6 mGy, assuming a fallout arrival time of 3 h and a medium level of fractionation. Finally, 0.50 Gy of absorbed dose in air was derived as our tentative estimate for 1-year cumulative external dose in Dolon due to local fallout from the first USSR test in 1949.

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A short analysis of all 111 atmospheric events conducted at the Semipalatinsk Test Site (STS) in 1949-1962 with regard to significant off-site exposure (more than 5 mSv of the effective dose during the first year after the explosion) has been made. The analytical method used to assess external exposure to the residents living in settlements near the STS is described. This method makes use of the archival data on the radiological conditions, including the measurements of exposure rate. Special attention was given to the residents of Dolon and Kanonerka villages exposed mainly as a result of the first test, detonated on August 29, 1949. For the residents of those settlements born in 1935, the dose estimates calculated according to the analytical method, are compared to those derived from the thermoluminescence measurements in bricks and electron paramagnetic resonance measurements in teeth. The methods described in this paper were used for external dose assessment for the cohort members at an initial stage of an ongoing epidemiological study conducted by the U.S. National Cancer Institute in the Republic of Kazakhstan. Recently revised methods and estimates of external exposure for that cohort are given in another paper (Simon et al.) in this conference.

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A methodology to assess internal exposure to thyroid from radioiodines for the residents living in settlements located in the vicinity of the Semipalatinsk Nuclear Test Site is described that is the result of many years of research, primarily at the Moscow Institute of Biophysics. This methodology introduces two important concepts. First, the biologically active fraction, is defined as the fraction of the total activity on fallout particles with diameter less than 50 microns. That fraction is retained by vegetation and will ultimately result in contamination of dairy products. Second, the relative distance is derived as a dimensionless quantity from information on test yield, maximum height of cloud, and average wind velocity and describes how the biologically active fraction is distributed with distance from the site of the explosion. The parameter is derived in such a way that at locations with equal values of relative distance, the biologically active fraction will be the same for any test. The estimates of internal exposure to thyroid for the residents of Dolon and Kanonerka villages, for which the external exposure were assessed and given in a companion paper (Gordeev et al. 2006) in this conference, are presented. The main sources of uncertainty in the estimates are identified.

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Methods to estimate external dose from radioactive fallout from nuclear tests have for many years depended on two types of data: measurements of exposure rate in air and an empirically derived power function to describe the change in exposure rate with time, Over the last four years, a working group with American and Russian participation has developed a bi-national joint methodology that offers an improved capability for estimating external dose. In this method, external dose is estimated using exposure rate functions derived from data from American nuclear tests similar in construction to SNTS (Semipalatinsk Nuclear Test Site) devices. For example, in this paper, we derive doses for test #1 (August 29, 1949) at the SNTS using an exposure rate function for the U.S. TRINITY test. For the case of test #1, the average external dose for a person in Dolon is estimated to have been about 0.5 Gy compared to 1 to 2 Gy estimated in other work. This prediction agrees better with reported EPR measurements in teeth from village residents and with measurements of TL signals in bricks from Dolon buildings. This report presents the basic elements of the joint methodology model for estimation of external dose received from SNTS fallout.

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Spatial distributions of soil contamination by ¹³⁷Cs (89 sampling points) and ^239+240Pu (76 points) near and within Dolon village were analyzed. An essential exponential decrease of contamination was found in Dolon village: the distance of a half reduction in contamination is about 0.87-1.25 km (in a northwest-southeast direction from the supposed centerline of the radioactive trace). This fact is in agreement with the available exposure rate measurements near Dolon (September 1949 archive data): on the basis of a few measurements the pattern of the trace was estimated to comprise a narrow 2 km corridor of maximum exposure rate. To compare computed external doses in air with local dose estimates by retrospective luminescence dosimetry (RLD) the gradient of radioactive soil contamination within the village was accounted for. The computed dose associated with the central axis of the trace was found to be equal to 2260 mGy (calculations based on archive exposure rate data). Local doses near the RLD sampling points (southeast of the village) were calculated to be in the range 466-780 mGy (averaged value: 645+/-70 mGy), which is comparable with RLD data (averaged value 460+/-92 mGy with range 380-618 mGy). A comparison of the computed mean dose in the settlement with dose estimates by ESR tooth enamel dosimetry makes it possible to estimate the "upper level" of the "shielding and behavior" factor in dose reduction for inhabitants of Dolon village which was found to be 0.28+/-0.068.

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The Semipalatinsk nuclear test site area is considered to have been highly contaminated with radioactive fallout during 40 years of continuous nuclear testing. Individuals living near the nuclear test site are considered to have been exposed to both internal and external radiation. In order to assess the effects of prolonged radiation, a chromosome analysis was performed in lymphocytes from 123 people living in three villages, Dolon, Sarjar and Kaynar, and 46 control people in Kokpekty. A micronucleus assay was also conducted in 233 people in six different contaminated villages and one control village. Frequencies of dicentric and ring chromosomes were higher in residents of the contaminated area (1.55-2.56 per 1,000 cells) than those of the non-contaminated area (0.78 per 1,000 cells). Frequencies of dicentric chromosomes with fragments were also higher in the exposed group (0.44-0.96 per 1,000 cells). Among residents of the four villages, the incidence of multiple complex chromosome aberrations (MCA) was 0.03-0.34%. Incidences of micronucleus were also higher in the exposed group (9.36-12.3 per 1,000 lymphocytes) than the non-exposed group (7.25 per 1,000 lymphocytes). The higher incidence of unstable-type aberrations such as dicentric, ring chromosomes and micronuclei found in residents of contaminated areas seems to be mainly caused by internal exposure and other factors.

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In this paper, the results of a biodosimetry investigation are reported for two villages in the area of the Semipalatinsk nuclear testing site: Chekoman and Dolon. Chekoman village is considered to be relatively less affected by radiation in comparison with Dolon village. The distance between the two villages is about 100 km and the life styles of the residents are similar. Chromosome aberrations in lymphocytes collected from the residents of the two villages were analyzed using the fluorescence in situ hybridization technique. Our results showed that the average frequency of stable translocations for the Dolon group was significantly greater that of the Chekoman group. The elevated level of stable translocations with the Dolon residents corresponds to a dose of about 180 mSv.

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Chromosomal studies in peripheral lymphocytes from 63 residents near the Semipalatinsk nuclear test site, at ages of 52-63 years old, were performed in 2001-2002. A higher rate of chromosome aberrations was observed in the two contaminated villages, Dolon and Sarjal, compared with the control village, Kokpekti. Moreover, a relationship of frequency of cells with radiation induced chromosome aberrations and the previously estimated exposure dose was observed. Furthermore, apparent nuclear abnormalities (ANA) of thyroid follicular cells were studied in 30 out of 63 residents, who were examined for chromosome aberrations. A higher rate of ANA was also found in the residents in the exposed villages compared with those in the control village. These results suggest radiation effects both on the chromosomes in peripheral lymphocytes and on the follicular cells in the thyroid.

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From 1949 to 1989, 488 nuclear explosions were carried out in Semipalatinsk, and the cancer risk is increased in this region. Measuring somatic-cell mutation frequencies may be a useful tool for evaluating cancer risk within radiation-exposed populations. Here, we report the first evidence of increased T-cell receptor (TCR) mutations in peripheral blood from radiation-exposed residents of Semipalatinsk. The TCR mutation frequency in the highly exposed residents (Dolon and Sarzhal) was significantly higher than in the control group (Kokpekti). There was no statistically significant difference between the control group and the weakly exposed group (Kaynar and Semipalatinsk-city). The TCR mutation assay appeared to be a useful biological dosimeter even after a period of 40 years since radiation exposure. This may be the result of specific conditions, such as the presence of internal exposure.

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The risk of radiation-induced nodules is higher than the risk for radiation-induced cancer. Risk factors and specific modifiers of the dose-response relationship may vary among different populations and not be well recognized. Many thyroid studies have considered thyroid nodularity itself, but not specific morphological types of thyroid nodules. There are many specific types of thyroid nodules which follow a morphological classification of thyroid lesions, including some congenital and tumor-like conditions. Modern equipment and technique can help us to identify particular specific types of thyroid nodules. In this study we report some results of a clinically applicable approach to materials derived from three studies.
From 1999 through 2002, we have screened 571 current residents from 4 exposed and 1 control village near the Semipalatinsk Nuclear Test Site area, who were of similar ages (<20) at the time of major radiation fallout events at the SNTS. Prevalent nodules were identified by ultrasound and fine-needle aspiration biopsy, cytopathology results. Analysis of ultrasound images and cytopathology of thyroid lesions among exposed and non-exposed population allowed us to distinguish some interesting ultrasound features for specific types of thyroid nodules. We believe that it would be interesting and possibly more informative for thyroid dosimetry studies to consider specific morphological types of thyroid nodules. We need more detailed research to clarify the feasibility of applying these findings for study of the dose-response relationship.

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The present paper reports progress and problems in our development of a database for comprehensive epidemiological research in Semipalatinsk whose ultimate aim is to examine the effects of low dose radiation exposure on the human body. The database was constructed and set up at the Scientific Research Institute of Radiation Medicine Ecology in 2003, and the number of data entries into the database reached 110,000 on 31 January 2005. However, we face some problems concerning size, accuracy and reliability of data which hinder full epidemiological analysis. Firstly we need fuller bias free data. The second task is to establish a committee for a discussion of the analysis, which should be composed of statisticians and epidemiologists, to conduct a research project from a long-term perspective, and carry out the collection of data effectively, along the lines of the project. Due to the insufficiency of data collected so far, our analysis is limited to showing the trends in mortality rates in the high and low dose areas.

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The main objective of this paper is to identify salient experiences of those who were exposed to radiation by the nuclear tests at the Semipalatinsk Nuclear Tests Site (SNTS). In 2002, our research team of the Research Institute for Radiation Biology and Medicine, Hiroshima University, started to conduct some field research by means of a questionnaire survey. Through this, we expected to examine the health condition of the residents near the SNTS, identify their experiences from the nuclear tests, and understand the exposure path. This attempt at clarifying the reality of radiation exposure at Semipalatinsk through the use of a survey research method is the first of its kind.
Among the responses to our survey, the present paper focuses mainly upon responses to the questions concerning the experiences of the nuclear tests. It deals mainly with direct experiences of nuclear tests of the residents characteristic to Semipalatinsk, including some new experiences hitherto unnoticed. The present paper touches upon their concrete direct experiences of flash, bomb blast, heat, rain and dust. We also discuss distinct experiences in Semipalatinsk such as evacuation, through the additional use of their testimonies. The data have been compared with the results obtained in a similar survey made in Hiroshima and Nagasaki. For the data analysis, a statistical method called logistic multiple linear regression analysis has been used.

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The main objective of the present paper is to explore the effects of radiation exposure on the inhabitants near the Semipalatinsk Nuclear Tests Site (SNTS), Kazakhstan. Our research team of the Research Institute for Radiation Biology and Medicine, Hiroshima University, started in 2002 to conduct a field research study using questionnaire surveys. The present paper attempts to clarify health effects and mental problems on the inhabitants by using our questionnaire surveys.
Among the responses to our survey, the present paper focuses upon responses to the questions concerning their health and mental problems. The data in Semipalatinsk have been compared with the results obtained in a similar survey conducted by Hiroshima and Nagasaki cities. The results show: (1) 33% of the residents replied that they felt bad or had very bad health conditions. (2) 70% of the residents strongly recognized a causal relationship between their bad health conditions and the nuclear tests. (3) The diseases that over 30% of respondents possessed are arthralgia/ lower back pain/ arthritis, high-blood pressure, heart disease and digestive system disease. (4) Acute radiation injuries from 1949 to 1962 that over 20% of respondents experienced were headaches and general malaise. (5) Concerning their mental condition, 22% of respondents felt easily frustrated and agitated and 21% experienced nightmare.

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The present paper is part of an attempt at finally reconstructing the realities of nuclear tests and their human effects near Semipalatinsk, Kazakhstan. As a first step, it tries to reconstruct the overall image of nuclear tests and their human effects. Our data are 199 written testimonies of those affected by radiation, which were collected in 2002 and 2003. We statistically processed them, and categorized those words and expressions, which occurred most frequently in the testimonies, and obtained some forty categories, which represent the experiences, feelings, desires of those affected by radiation. Next, we conducted a principal component analysis of the categories. The result shows: (1) The experiences of the nuclear tests are arranged along the time axis, with direct experiences of the nuclear tests forming one coherent part of the perception and memory, and with other subsequent experiences forming another. (2) Of the latter, we can discern a core of the experiences on human effects such as "disease," "death," "family," "radiation," and so on. (3) And around this core, we see two different trends: one pointing to the current distress and plight, and the other pointing to future fear and hope.

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