JP0150451 JAERI-Conf 2000-016

4.2 Present Situation of Radioactive Contamination In and around the Former 's Scmipalatliisk Nuclear Test Site

M. Yamamoto,1* M. Hoshi,2 J. Takada,2 T. Tsukatani,3 S. Oikawa,4 I. Yoshikawa,5 T. Takatsuji,5 A. Kh. Sekerbaev6 and B. I. Gusev6

'Low Level Radioactivity Laboratory, Kanazawa University, Ishikawa 923-1224, Japan 2InternationalRadiation Information Center, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8553, Japan 3Kyoto Instituteof Economic Research, Kyoto University, Kyoto 606-8501, Japan 4Japan ChemicalAnalyticalCenter, Inage, Chiba 263-0002, Japan 5Faculty of EnvironmentalStudies, Nagasaki University, Nagasaki 852-8521, Japan 6Kazakh Scientific Research Institute for RadiationMedicineand Ecology, Semipalatinsk, The Republic

Abstract Field missions were sent to the Semipalatinsk regions to investigate the present radioecologicalsituationas a a result of the radioactivefalloutfrom nucleartest explosions carried out at the former Soviet Union's Semipalatinsk nuclear test site (SNTS). For this purpose, surface and core soil samples were collected at more than 60 sites, including several settlements such as Dolon, and Sarzhal, within and outside the SNTS territory. The radioactivities of long-lived radionuclides, l37Cs, 238Pu and 239-240Pu, and the atomic ratio of 24oPu/239Pu were determined in combination with non-destructive g-ray spectrometric method and radiochemical separation followed by a-particle spectrometric 137 239 a40 and/or ICP-MS methods. The results showed a distinction of Cs and - ptt inventories in soil depending on a sampling sites. Although 137Cs was within typical environmental levels except for the area near the first nuclear test site and Balapan, 239240Pu was at elevated levels in all areas we visited. This high Pu contamination was recognized to be due to the weapons-grade Pu from the SNTS by the measurement of 24OPu/239Pu atomicratioin soil samples.

Keywords Atomic bomb, Semipalatinsk, Former USSR, Radioecology, Long-lived radionuclides, 137Cs, 239>24° Pu, ^Pu/^Pu atomicratio, Residual radioactivity, Soil

* To whom all correspondence should be addressed.

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Introduction

The Former USSR program was mainly carried out at two test sites: one is the Novaya Zemlya test site in the Russian Arctic for large yield tests (total yield of atmospheric tests about 240 megatons) and the other the Semipalatinsk nuclear test site ( hereafter referred to as SNTS) in the northeast corner of Kazakhstan for smaller yield tests (about 6.6 megatons). Most of the tests at the former site were conducted at high altitudes, minimizing local fallout At the latter test site (approximately 18,500 km2, see Fig. 1), 456 nuclear tests were conducted over a period of 40 years from the first on 29 August 1949 through the last on 19 October 1989, including 86 atmospheric, 30 surface and 346 underground tests (Fig. 1) (Bocharov et al., 1989; Dubasox etaL, 1994; Shapiro etaL, 1998). In the SNTS, the experiments were performed at the different places within the territory and varied in type and size, and resulted in the local and global dispersion of radioactive materials. As a consequence, residual radioactivities in the soil from 137 90 23823924024t 241 long-lived radionuclides, such as Cs, Sr, pu and Am, are still observed in the area today. These nuclides remaining on the land have a potentialhuman hazard in the long time. The principal hazard from nuclear test explosions to human is from local (early) fallout from atmospheric ground and near -ground bursts. Some of the underground nuclear tests also emitted a huge amounts of gaseous radionuclides on the ground. Hence, the effects of human health by ionizing radiation - effects of long-term protracted low-dose radiation exposure on human in particular - of scientific and practical importance, together with an assessment of the impact of the nuclear tests on radioactive contamination of land. Information on the radiation situation there is, however, very limited (Tsyb etal., 1990;Gusev, 1993; Stepanov et al., 1994; Logachev, 1994; Shapiro etcd., 1998). Recently, in connection with the "opening" of the SNTS, intensive studies have, at long last, begun (Takada et al., 1996; Yamamoto et al., 1996a; Yamamoto et al., 1996b; Kazachevskiy et al., 1998; Shebell and Hutter, 1998; Yamamoto et al., 1998; Yamamotoef al, 1999). To serve as an aid to resolve such problems in the SNTS region, studies have begun to investigate the present situation of radioecology in and around the SNTS. Emphasis has been placed to the radioecology of Pu, because any systematic data or studies have not been performed until now. Three objectives are considered in this paper: (1) an evaluation of geographic distribution of 239'240Pu, including 137Cs, in soil samples within and 239 240 outside the SNTS, (2) an information about geochemical association of ' pu with soil, and (3) an identification of the contamination sources of Pu and 137Cs in the soil with 24OPu/239Pu isotopic ratios. The data used in this paper include the field studies on

-173- JAERI-Conf 2000-016 residual radioactivities in and around the SNTS carried out during the last five years and some of the data have been already published elsewhere (Yamamoto et al., 1996a; Yamamotoefai, 1996b; Yamamotoef al, 1998; Yamamotoe? al, 1999).

Materials and Methods (A) Soil sampling Soil samples were collected for measurement At each site, three to five surface soil samples were taken at a spacing 2-3 m apart from each other, with a diameter of 4.7 cm and a depth of 10 cm. Furthermore, a A.I cm diameter core soil sample was taken at the center of the surface soil sampling spots by inserting a stainless steel pipe to a depth of about 30 cm. While 10 cm-deep soil samples were not divided, most of the 30 cm-deep core samples were subdivided carefully into 6 parts of 0-5, 5-10, 10-15, 15-20, 20-25 and 25-30 cm depth from the surface. After air-dried and crushed, these samples were sifted through a 2-mm mesh screen to remove pebbles. The following samples were used. (l)Soil samples within the territory of the SNTS (Fig. 2 and Appendix I) In 1995, in collaboration with the National Nuclear Center (NNC) in Kazakhstan, soil samples were collected along the road between Kurchatov and the hypocenter of the first nuclear test, around the hypocenter, and along the roads from Kurchatov to the underground nuclear test sites in the south direction (Balapan and Mt Degelen). Soil samples were also collectedin Sarzhal, settlementlocatedto the southeast of the SNTS. (2) Soil samples outside the SNTS (Fig. 4 and Appendixes I and II) From 1995 to 1997, soil samples were collected by the same method used for the soil samples within the SNTS as a collaborative study with the Kazakh Scientific Research Institute for Radiation Medicine and Ecology. Sampling sites are Mostik, Dolon, Chagan, etc., - adjoining settlements of the SNTS, where exposure doses are reported to be relatively high. The samples were also collected from Semipalatinsk City and some settlements including Korosteli, to the north of Semipalatinsk City in the direction of the Altai District, and the roads between Semipalatinsk City and Ust' -Kamenogork City and it's adjoining areas.

(B) Radioactivity measurement Soil sample (50-80 g) was first placed into a plastic container with an inner diameter of 6 cm and a depth of 2 cm. After stored for about 3 weeks, gamma-emitting radionuclides were determined by gamma-ray spectrometry using a low background Ge detector for 137Cs and other gamma-ray emitters and a planar type Ge detector (low energy photon spectrometer: LEPS) for 210Pb and 234Th (238U). The spectrometers were calibrated with

-174- JAERI-Conf 2000-016 standards prepared from New Brunswick Laboratory (NBL) reference materials No. 42-1 (4.04 % uranium) and anaiyticalgrade KG. As for Pu, Pu and ' Pu concentrations in soil were mainly determined together with 24oPu/239Pu atomic ratio. It is well known that Pu in soil contaminated with global fallout can be extracted almost quantitatively by leaching with heat using mineral acids such as nitric acid (Japanese Science and Technology Science, 1979). However, concerning local (close-in) fallout Pu in a nuclear test site, the studies of the U, S. Nevada nuclear test site and it1 s surrounding areas showed that there were refractories, and some fractions were trapped in melted atomic bomb components and hydrated silica soil grains ( Krey and Hardy, 1970; Hardy etal., 1972; Hardy, 1976; Krey and Bogen, 1987). Careful leaching or dissolution of Pu becomes , therefore, key point for analysis. For the 10 cm deep soil samples, a stepwise leaching for Pu analysis using 20-40 g of the dried samples was particularly adapted to get information on the geochemical association of Pu with soil components. Before starting the analysis, the dried sample was ashed at about

500 Ae* and the following method was used in order; (1) leaching with c.HNO3+H2O2 ,

(2) leaching with a mixture of 10M HNO3 and 0.1M HF and (3) complete decomposition

of the residue by alkali (NaOH) fusion or decomposition with HNO3+HF+HC1O4 . As for core soil samples, aliquots (10-50 g) of the dried samples were at first ashed at about

500 Ae" and then were, without stepwise leaching, decomposed with a mixture of HNO3 a42 and HF, followed by HC1O4 , in the presence of Pu as a yield tracer. On the other hand, for the measurement of the 24OPu/239Pu atomic ratio, an aliquots of 20-50 g of the dried sample were decomposed in a manner similar to the method described above, in the absence of a yield tracer such as 242Pu by taking into account of the possible contamination of Pu isotopes from the added tracer. in each fraction obtained from the above procedures was separated and purified using an anion-exchange column method to determine 238Pu and 239240Pu with an a-particle spectrometry after electrodeposition onto a stainless steel disk. A part of the purified Pu fraction was sometimes subjected to the b-ray (241Pu) counting by a low background liquid scintillation counter (LSC-LB1, Aloka). The z4oPu/239Pu atomic ratio was determined by high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) (Yamamoto et al, 1996b; YamamotoefaZ, 1998).

Results and Discussion

Accumulated levels (inventories) of """PD and 137Cs Although the emphasis in this work is on plutonium deposited in and around the SNTS, the soil sampled was analyzed for the fission product 137Cs to compare with 239l240Pu and

-175- JAERI-Conf 2000-016 to get information on 239>240Pu/137Cs activity ratios. The l37Cs results in soil samples within the territory are shown in Fig. 3, in terms of inventory in Bq/m2. The inventory of 137Cs found in the surface soil (10 cm in depth) is shown by the black bar and that of core soil (30 cm in depth) by the white bar. The data of I37Cs were correctedfor decay to the date of sampling. The highest value was found at F6 ( 104-105 Bq/m2) and F5 (ca. 104 Bq/m2), which are in proximity to the hypocenter of the first Soviet atomic bomb (29 August 1949), but the values gradually decreased with increasing distance towards Kurchatov. In other areas within the territory we visited, there was no site which showed markedly high level, the levels ranged from 2xlO3 to around 104 Bq/m2 at the maximum with a fairly random deposition pattern. The 137Cs inventory levels in Sarzhal settlement (S-series in Fig. 3), which was impacted heavily by the first hydrogen bomb (12 August 1953), was about 5xlO3 Bq/m2 on average. However, hot spot-like sites such as S5 whose level is as high as 104 Bq/m2, also exist sporadically. Such a trend was also observed for the inventories of 137Cs outside the territory of the SNTS (Fig. 5). The levels in Mostik, Dolon and Chagan settlements, which are reported to have received relatively high radiation dose due to heavy local fallout from the SNTS (Gusev, 1993), were ranging from 103 to 5xlO3 Bq/m2. The level at W8 in pine forest sand near Dolon showed higher levels of 5X103 - 7xlO3 Bq/m2. For the samples collected along the roads between Semipalatinsk City and the Altai District (N-series in Fig. 5(a)), the levels were within lxlO3 - 3xlO3 Bq/m2. Furthermore, the 137Cs measurements in the distant areas which extend from Semipalatinsk City to Ust'-Kamenogrosk City, the minimum direct distance of ca. 150 km east of the Semipalatinsk City, were also performed to check the possibility of transport of radioactive products from the atmospheric nuclear explosions at the SNTS. The results are shown in Fig. 5(b). The 137Cs inventories in these areas show a random but fairly uniform deposition pattern, with the nearly same levels (mostly, 2xlO3 - 4xlO3 Bq/m2 ) as those around the Semipalatinsk City. As a whole, in the outside areas of the SNTS, there is no obvious gradation from high to low deposits with increasing distance from the SNTS, but some variable fraction of the measured 137Cs might be due to the local fallout from the SNTS. Concerning the global fallout levels of 137Cs for the Semipalatinsk regions, no data seem to exist, but the average level for the Altai region in the north direction of Semipalatinsk City is only reported to be about 50 mCi/km2 (1,850 Bq/m2 ) (Shapiro et d., 1998). In Japan, the inventory of global fallout 137Cs is within the range of 6X103 - 8X103 Bq/m2 for the Japan Sea coast, which has more precipitation (2,000-2,500 mra/y), and of 3xlO3 - 4xlO3 Bq/m2 for the Pacific coast, which has less precipitation (around 1,000 mm/y ) (Yamamoto et al., 1983). Figure 6 shows the the results of 239l240Pu measurements for the surface samples (10

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cm in depth) with the highest 137Cs concentration (Bq/kg) and the core samples (30 cm in depth) at each site. As seen in this figure, the239'240Pu inventories are remarkably high at F6 (3.3xl05 Bq//m2 for the core sample up to a depth of 23 cm) near the hypocenter of the first nuclear test and at F5, F4, andF3 (lxl04-4xl04Bq/m2) locatedfurther away from F6 towards Kurchatov. The inventories in Sarzhal settlement is around 103 Bq/m2. The 239Z40Pu levels outside the territory such as Dolon and its adjoining pine forest (W-series in Fig. 5(a)) along the road towards Semipalatmsk City varied largely, ranging from a few hundreds to around 103 Bq/m2, with some sporadic sites whose levels are (2-4) xlO3 Bq/m2. Those in Semipalatinsk City and in the areas (N-series in Fig. 5(a)) in the direction of the Altai District showed a lower values of a few tens to several 100 Bq/m2. The same levels was also found in the samples collected along the roads from Semipalatinsk City towards Ust' -Kamenogorsk City and at its surrounding areas. Unlike 137Cs, the inventories of 239240Pu for most of the sites within the SNTS territory and around Sarzhal settlement, and for some sites (W-series) from Kurchatov towards Semipalatinsk City are several to a few hundred times higher than those (40-120 Bq/m2 ) for global fallout found in Japan (Yamamoto et d., 1983). These results indicate that nuclear tests conducted at the SNTS produced local fallout Pu even in the outside regions

Activity ratios of 23V40P«/137Cs and ^Pw/239'240 P« When considering the data of soil as a whole, valuable information can be derived from the activity ratios among Pu, including 137Cs. The above mentioned 239>240Pu inventory was plotted against 137Cs inventory in Fig. 7. The lines in the figure show the ranges of 137Cs and 239240Pu levels and 239240Pu/137Cs activity ratios (0.02-0.03) for global fallout found in Japan, respectively. Recently, Hodge et al. (1996) reported, based on measurements of soil samples (total 155 sites) throughout the northern hemisphere, that the 239 24OPu/137Cs activity ratios for global fallout is 0.029A}0.03 as of 1 July 1998. Most of values found here are several times higher than the above ratio for global fallout By taking into account that I37Cs level, except for the areas near the hypocenter of the first nuclear test, was within or a little lower than typical environmental levels of global fallout, the higher 239|240Pu/137Cs activity ratios also indicate that there were additional input of local fallout239240 Pu from the atomicexplosions at the SNTS. The 238Pu/239i240Pu activity ratio in soil from the global fallout is well known to be in the range from 0.03 to 0.04 in the Northern Hemisphere (Yamamoto et al., 1990). The

238puy239.240pu activity ratios for me surface QO cm jn depth) and core (30 cm in depth ) samples within the territory were found to be 0.007-0.04. The activity ratios in most of the samples was 0.02-0.03. These values appear to be not much different from the values

-177- JAERI-Conf 2000-016 for the global fallout The lower values (less than 0.01) were dominantly observed for the samples collected from the Sarzhal settlement. One probable reason of this low ratio may be due to the fact that this area was mainly contaminated by a local fallout from the first Soviet Union's hydrogen charged detonation on 12 August 1953. The 238Pu/239'240Pu activity ratios for soil samples outside the SNTS, including Ust1 -Kamenogorsk area, varied between 0.019 and 0.047 with a mean value of 0.029 A} 0.007 (n=36).

Depth profiles of 2*M0Pn and I37Cs Typical depth profiles of 239l240Pu, including 137Cs, for soil core samples obtained within and outside the SNTS are shown in Fig. 8. While forested areas were almost pine sand, other areas except pasture land were bare land (loam and brown soil), which was so hard that it was difficult to drive a stainless pipe into the ground. A@ As it is clear from this figure, though239'240 Pu and 137Cs were observed even in the layer up to a depth of 30 cm at some sites , most of them were concentrated in the upper 5 cm or 10 cm layer of the soil. At the most of sites within the territory where we visited, they were found in the upper 5 cm layer of the soil (F4 site in Fig. 8). In the sand area such as forest ,239'240Pu and 137Cs were often found down to a depth of 30 cm, whereas penetration into soil of these nuclides seemed rather slow in the loam and brown soil areas. By analyzing a pine forest sand collected in Dolon, Stepanov et d. (1994) reported that the highest levels of radionuclide penetration into soil were observed in the deep layer of 50-70 cm for the period 1959-1962. Furthermore, Tsyb et al. (1990) reported, for the core soil samples from Dolon , that the depth profiles of 90Sr, 137Cs and 239l240Pu concentrations showed a maximum concentrations at a subsurface of 10-15 cm depth. For the depth profile studies of the radionuclides, strictly speaking, undisturbed area must be selected and core soil sample must be carefully collected. However, it must be kept in mind that there are many locations which surface soil was mixed with deep soil , especially around settlements, in order to reduce the high activity concentration of local fallout radionuclides on the surface (Gusev, 1995). 39'240Pu and 137Cs penetrating to greater depth may be resulted from this artificial stir of soil. In fact, for the 30 cm core samples from N- and U-series, both nuclides were clearly detected even in the layer of 25-30 cm depth at the many locations. Soil sampling up to a sufficient depth is , therefore, required for estimating the inventory of these nuclides at such areas.

Geoeheinlcal association of Pa with soil A stepwise leaching using the surface soil samples (10 cm in depth) was performed to investigate the geochemicalassociationof Pu with soil. The results are graphicallyshown

-178- JAERI-Conf 2000-016 in Fig. 9. As it is clear from this figure, at every sites 239<240Pu in soil can not be fully extractedby a hot digestion with c.HNO3 containinga small amount of H2O2, even when followed by digestion with a mixture of 10M HNO3 and 0.1M HF. The HF was used to solubilizeany refractory forms of Pu (Japanese Science and Technology Science, 1979). For the soil within the territory, a large quantity (60-80%) of Pu remained in the last leached soil residue, except for the samples (F-series in Fig. 9) collected along the road between the hypocenter and Kurchatov. The occurrence of relatively large amounts of refractory forms of Pu, fraction extracted by a mixture of 10MHN03 and 0.1M HF, was especially found in the samples of F-series. These areas are said to be mainly contaminated by the local fallout from the first nuclear explosion on 29 August, 1949. On the other hand, for the soil outside the territory, (he quantity of Pu remaining in the last soil residue varied on a place; 97% at W5, 80-85% at W2 and W8, and 20-40% at distant N1-N5 and at great distance from Semipalatinsk City towards Ust' -Kamenogorsk City. Generally , the fraction of Pu remaining in the last soil residue seems to decrease with increasing distance from the SNTS. Considering that Pu in soil contaminatedwith global fallout can be extracted almost quantitatively by leaching with heat using mineral acids such as nitric acid, HN03 +H2O2 leached Pu this time probably may consists of global fallout Pu and a fine particles of local fallout Pu derived from the SNTS. The 10M HN03 + 0.1M HF leaching method has generally been applied for samples possibly containing refractory forms of Pu. Pu in the last soil residue is thought to be Pu tightly incorporated into various size of particles formed in the course of the condensation of melting materials, such as vaporized soil and atomic bomb components. Such knowledge will be particularly important in predicting and evaluating the long-term transport of Pu in soil of this dried area and for estimating the radiological Pu hazard associated with the inhalationof the contaminatedfine soil.

Pu Isotopk Composition of SNTS Pu isotopic composition of the SNTS was determined using surface soil samples from the two heavily contaminated areas; the first nuclear explosion site and the Chagan River site. The former soil sample ( ca. 1 cm in depth) was collected near the hypocenter , while the latter sample ( ca. 5 cm in depth) was collected from the top of a bank of a crater (Atomic Lake) of about 100 m in depth and 552 m in diameter, called domestically as Bolapan or Balapan, formed by the underground hydrogen explosion on 2 January , 1965, with a supposed yield of 100-150 kt The atomic ratios of 24OPu/239Pu measured by HR-ICP-MS are given in Table 1, together with those from the other Pu contaminated areas. The obtained values are significantly lower than the value of 0.18 commonly accepted for the global fallout, and are nearly the same as the values of 0.042-0.063

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found for soil (Hardy, 1976), weapon-grade Pu fabricated at the Rocky Flats Plant (Krey and Hardy, 1970), Thule sediment from Greenland and Nishiyama soil from Nagasaki in Japan (Komura et d. 1984). This indicates that most of the Pu in the soil samples of the first nuclear explosion site and Balapan are bomb-derived Pu, that is, weapons-grade Pu escaped fission. All Pu isotopes measured for these two soil samples are summarized in Table 2. At the first nuclear explosion site, an extremely high level (27.9 Bq/g) of239'240Pu was detected in the surface soil and its Pu isotopic composition was 238Pu 0.006%, 239Pu 96.5%, 240Pu 3.48%, 241Pu 0.01% and 242Pu 0.004%. At Balapan, a high level (8.85 Bq/g) of 239i240Pu was also detected with Pu isotopic composition of ^Pu 0.19%, ^Pu 93.4%, ^Pu 6.30%, MPo 0.08% and^Pu 0.03%. These values should be compared with the data by Krey and Krajewski (1972) who reported the isotopic composition for a typical Pu prepared for fabrication and the data (shown in parenthesis) from Nishiyama in Nagasaki (Komura et al. 1984): 238Pu 0.04% (0.03%), 239Pu 93.8% (96.3%), 24oPu6% (3.6%), 24IPu0.58% (0.07%) and 242Pu 0.04%.

Identification of contamination sources of Po and OTCs As described above, 137Cs and 239'240Pu from local fallout as well as from global fallout intermingle in soil within and outside the SNTS territory. It is extremely important to differentiate global fallout-derived components and to have accurate knowledge of local fallout-derived 137Cs and 239240pu concentrations and their inventories - especially for reconstruction of radiation exposure doses of the residents. It is also essential to evaluate the transfer and behavior of Pu in the dried area from both sources of contamination. One of the differentiation methods is to use atomic ratios of 24OPu/239Pu of Pu isotopes, developed by Krey and Hardy (1970), Hardy et cL (1972) and Hardy (1976). More recently , Cizdziel et al. (1999) reported a method for resolving Nevada test site and global fallout Pu in attic dust and soils using i37Cs/239'240Pu activity ratios. The atomic ratio of 24OPu/239Pu changes depending on a contamination source. If we have a typical atomic ratio of 24OPu/239Pu of the samples and weapons-grade Pu of the Semipalatinsk nuclear tests, it is possible to differentiate Pu by me following formula (Krey and Hardy, 1970; Hardy etal, 1972; Hardy, 1976) using global fallout value of 0.18.

(Pu)w/(Pu)G = Y = [(R,,- R,, )/(Rg - Rw)] x[(l+3.73Rw )y(l+3.73RG)] --(1)

(Pu)G + (Pu)w =(Pu)s (2)

(Pu)G = [l/(l+Y)]x(Pu)s (3)

239 M0 2 (Pu)s : Inventory of - Pii in the sample (Bq/m )

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(Pu)G : Inventory of global fallout-derived ' Pu in the sample (Bq/m ) 239 240 (Pu)w : Inventory of local fallout-derived ' Pu from the Semipalatinsknuclear tests in the sample (Bq/m2) Rs : Atomicratio of 24OPu/239Pu of Pu in the sample Re : Atomicratio of ^Pu/^Pu of global falloutPu: 0.18 24O 239 Rw : Atomicratio of Pu/ Pu of local falloutPu from the Semipalatinsknuclear tests Y : Contributionratio of local fallout ^^Pu to global fallout ^^Pu

Of the above parameters, Rg can be easily obtained through the sample measurements. RQ can be obtained by measuring Pu in soil contaminated by global fallout Pu only, and is well known to have a value of around 0.18. The most difficult parameter to evaluate is the value of Rw. Since various types of nuclear tests varying in magnitude have been conducted, atomic ratio of ^Pu/^Pu seem different for each nuclear test Trajectories of various radioactive plumes are thought to intermingle over the sampling sites. Therefore, the value of Rw is unlikely to be constant in the whole Semipalatinskarea. The Rw value should be decided for each sampling site or area. When (Pu)G is calculated by the above formulate, it is also possible to differentiate 137Cs using the following formula (Krey and Hardy, 1970; Hardy et a/., 1972; Hardy, 1976).

l37 137 I37 ( Cs)w = ( Cs)s - ( Cs/Pu)G x (Pu)G (4)

137 137 2 ( Cs)s : Inventory of Cs in the sample (Bq/m ) 137 37 2 ( Cs)w : Inventory of local fallout-derived Cs in the sample (Bq/m ) 137 137 239240 ( Cs/Pu)G: Activityratioof global fallout-derived Cs/ Pu in soil

137 Although ( Cs/Pu)G value may vary a little by regions, soil properties and so on, at present, its mean activity ratio throughout the northern hemisphere is estimated to be 34 A}4 as of 1 July 1998 by Hodge etal (1996).A@ Figure 10 shows the results of atomic ratios of 24OPu/239Pu measured for the surface soil samples (10 cm in depth) from the areas within and outside the SNTS territory. As seen from this figure, the atomic ratios of 240Pu/ 39Pu for samples within the territory showed fairly low values in the range of 0.025 to 0.072 compared to the global fallout value of 0.18. Outside the territory, except W5, W8 and 2N1 which showed low values less than 0.05, the other sites showed values higher than 0.05. The atomic ratios vary considerably among the sampling sites, but generally their ratios seem to increase with increasing distance from the SNTS. These low values strongly suggest thatPu contained

-181- JAERI-Conf 2000-016 in an atomicbomb itself was scattered around. The 24OPu/239Pu atomicratios obtained this time are quite similar to the atomic ratios such as the weapons-grade Pu (0.054-0.063) at the Nevada nuclear test site (Hardy, 1976) and weapons-grade Pu (0.051) fabricated at the Rocky Flat Plant (Krey and Hardy, 1970). As to whether Pu with low atomic ratio of 24OPu/239Pu observed is Pu of weapons-grade one itself, Pu fractionated by absorbing neutrons and Pu isotopes generated by neutron capture of 238U may have contributed. However, at present, a majority of them are likely to be weapons-grade Pu. Assuming that the lowest 24OPu/239Pu ratio of 0.025 observed this time is a typical value of the Semipalatinsk nuclear tests, although it is speculative, 95-77% of 239l240Pu are thought to be due to the close-in fallout at the sites whose ratios are found to be in the range of 0.03-0.05. When the contribution of local fallout 137Cs is estimated using these values, some sites show negative values of 137Cs ( no contribution of local fallout 137Cs). As mentioned earlier, Rw values should be evaluated more accurately for each site or area. As an attempt to resolve this problem, we measured the atomic ratios of 24OPu/239Pu for both Pu components that can be leached with hot HNO3 + H2O2 and that can not, using the surface samples (10 cm in depth). The atomic ratio of 24oPu/239Pu in the soil residue that can not be leached with hot HNO3 + H2O2 may be considered to reflect the Rw value of local fallout Pu at each site. Table 3 shows the results applied for the some soil samples collected at the distant areas from Semipalatinsk City towards and within Ust' -Kamenogrosk City. As seen from this Table, while most of i21Cs (more than 90%) 239240 are leached with hot HN03 + H2O2, about half (40-50 %) of total pu measured was still found in the leached soil residue. The 24oPu/239Pu atomic ratios obtained in the soil residue were found in a narrow ranges from 0.039 to 0.046, and the values are clearly lower than the values (0.093-0.145) for their corresponding leachates. Using these data and equations (l)-(4), we have preliminary calculated the local and global fallout 239l240Pu contribution, including 137Cs, at each site and have listed them in Table 3. Clearly, 239240 137 there are some additional input of local fallout pu and Cs even in the distant areas about 300 km east away from the SNTS. Further works are, at present, in progress whether such a method is actually valid for the differentiation of contamination source of 137 239.240 p^ mcju£j}ng cs in the Semipalatinskregion or not.

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Conclusions

Although measurements are still continuing, the following results have been obtained through the measurements of a limited set of soil samples within and outside the SNTS territory. (1) While the overall I37Cs levels of the soil samples within and outside the SNTS territory were, exceptfor an area near hypocenter of the first nuclear test and Balapan, as same as or slightly lower than the global fallout levels (3xl03-7xl03 Bq/m2) of Japan, 239l240Pu levels were several to a few ten times higher than the level (40-120 Bq/m2) in the soil of Japan. (2) The 137Cs and 239240Pu in soil were often detected down to a depth of 30 cm from the surface, although most of them were found in the upper 5 cm or 10 cm layer of the soil. (3) From the stepwise leaching of Pu from the soil, Pu in soil from these areas was

found to be not fully extracted by an ordinary HNO3+H2O2 leaching with heat at

every sites. The quantity of Pu in the soil residue remaining after HNO3+H2O2 leaching varied in the range of 20-97 % depending on a place, indicatingthat some Pu was tightly incorporated into the various size of particles formed in the course of the condensation of melting materials such as vaporized soil and atomic bomb components (4) Most of all samples measured showed lower 24oPu/239Pu atomic ratios (around 0.05 within and near the SNTS territory ) than the value of 0.18 commonly accepted for the global fallout It is clear that the contamination was derived from weapons-grade Pu of atomic bomb materials itself in the Semipalatinsk nuclear test site. Differentiationof contaminationsources of Pu and 137Cs from global fallout and local falloutneeds further investigation.

Acknowledgements - The authors would like to express their deep gratitude to research staffs of the National Nuclear Center of Kazakhstan, the Kazakh Scientific Research Institute for Radiation Medicine and Ecology, Hiroshima University and Kyoto University for their cooperation with sampling. We are also grateful to Dr. A. Tusmura at the National Institute of Agro-Environmental Sciences for his assistance in measuring Pu isotopic ratio in soil sample. This work was supported by a grant in aid for scientific research from the Ministry of Education and Culture of Japan, Monbusho International Scientific Research Program during the periods of 1994-1995 and 1995-1997 represented by Professors T. Tsukatani and M. Hoshi, respectively.

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References

Bocharov V.S., Zelentsoz S.A., & Mikhailov V.N. (1989). Characteristics of 96 underground nuclear explosions at the Semipalatinsk test site (in Russian). Atomic Energ., 67,210-214. Cizdziel J., Hodge V., & Faller S. (1999). Resolving Nevada test site and global fallout plutonium in attic dust and soils using 137Cs/239'24flPu activity ratio. Health Phys. ,77, 67-75. Dubasov U.V., Zelentsov S. A., Krasilov G.A., Logachyov V.A., Matushchenko A.M., Smagulov S.G.,Tsaturov B.S., Tsirkov G.A., & Chernyshov A.K. (1994). Chronological list of the atmospheric nuclear tests at the Semipalatinsk Test Site and their radiological characteristics. In J.H.Shoikhet(Ed.). Scientific Research Institute for Regional Medical and Ecological Problem, Herald of the Research Program "Semipalatinsk Test Site-Altai" N4, 1994, Scientific and Practical Journal, Digest of the International Panel Meet "NATO/SCOPErRADTEST", Barnaul, September 5-10. Gusev B.I. (1993). Medical and demographical consequences of nuclear fallouts in some rural districts in the Semipalatinskregion (in Rissian). DoctoralThesis, Almati. Gusev B. I. (1995). Private communication. Hardy E.P. (1976). Plutonium in soil northeast of the Nevada test site. New York, NY. U.S. Atomic Energy Commission Health and Safety Laboratory, USAEC (pp. 1-51 toI-76). HASL-306. Hardy E.P., Krey P.W., & Volchov H.L. (1972). Plutonium fallout in Utah. New York, NY. U.S. Atomic Energy Commission Health and Safety Laboratory, USAEC (pp. 1-95 to 1-118). HASL-257. Hodge V., Smith C, & Whiting J. (19%). Radiocesiujm and plutonium: still fixed together in background soils after more than thirty years. Chemosphere, 32, 2067-2075. Japanese Science and Technology Agency. (1979). Analytical procedure for plutonium (in Japanese). Radiation manegement Series 12. Japan Chemical Analysis Center, Chiba, Japan. Kazachevskiy I.V., Solodukhin V.P., Khajekber S., Smirin L.N., Chumikov G.N., & Lukashenko S.N. (1998). Some aspects of determination of radionuclides at the former Semipalatinsknuclear test site./. Radioanal.NucL Chem., 235, 145-149. Kim C.K.(1990). Radioanalytical and environmental studies on long-lived radionuclides. Doctor thesis presented to Departmentof Chemistry, University of Tsukuba, Japan. KomuraK., Sakanoue M., & YamamotoM. (1984). Determinationof 24OPu/239Pu ratio in

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environmental samples based on the measurement of LX/alpha-ray activity ratio. HealthPhys., 46, 1213-1219. Krey P.W., & Krajewski B.T. (1972). Plutonium in soil around the Rocky Flats Plant New York, NY. U.S. Atomic Energy Commission Health and Safety Laboratory, USAEC (pp. 1-67 to 1-94). HASL-249. Krey P.W., & Hardy E.P. (1970). Plutonium in soil around the Rocky Plats Plant New York, NY. U.S. Atomic Energy Commission Health and Safety Laboratory, USAEC. HASL-235. Krey P.W., & Bogen D.C. (1987). Determination of acid leachable and total plutonium in large soil sample. /. Radioanal.Nucl. Chem., 115, 335-355. Logachev V. (1994). Feature of an evaluation of the radiation dose received by (he population after atmospheric nuclear testing at the Semipalatinsk. In: Assessing the Radiological Impack of Past Nuclear Activities and Events (pp. 25-35). TECDOC-755, IAEA. Vienna. Shapiro C.S., Kiselev V.I., & Zaitsev E.V. (1998). Nuclear tests, Long-term consequences in the Semipalatinsk/Altai region. NATO ASI series, 2. Environment - Vol.36, Springer-BerlinHeiderberg, Germany. Shebell P., & Hutter A.R. (1998). Environmental radiation and radioactivity in the vicinity of the Semipalatinsktest site. /. Radioanal.NucL Chem., 235 , 133-138. Stepanov Yu S., Andryushin LA., Chernyshov A.K., DarenskayaN.E., Krasilov G.A., Logachev V.A., Matuschenko A.M., MkhalikhinaL.A., &Shamov O.I. (1994). On estimation of external radiation doses of population as result of nuclear tests at Semipalatinsk test site. Abstract and paper presented^ NATO/SCOPE-RADTEST advancedresearchworkshop, Barnaul Russia, 5-10 September.

Takada J., Hoshi M., Endo S., Yamamoto M., Nagatomo T., Gusev B.I., Rozenson T. I., Apsalikov K. N., &Tchaijunusova N. J. (1996). Thermoluminescencedosimetry of gamma-rays from the fallout the Semipalatinsk nuclear test In M. Hoshi, J. Takada, R. Kim, &Y. Nitta (Eds.). Proceedings of the Second Hiroshima InternationaEymposium (pp. 195-199). Hiroshima University press Tsyb A.F., Stepanenko V.F., Pitkevich V.A., Ispenkov E.A., Sevankaev A. V., Orlov MYu., Dmitriev E.V.,Sarapultsev I.A., ZhigarevaT.L., Prokofev O.N., Obukhova O.L., Belovodskiy L.F., Karimov V.M., Rezontov V.A., Matushenko A.M., Katkov A.E., Vyalykh V.N., Smagulov S.G., Meshkov N.A., Saleev A.A., & Vildanov S.E. (1990). Around the Semipalatinsk proving ground: The radioecologival situation, radiation exposures of the population in Semipalatinsk Oblast (based on data from the report of the international commission). Radiologiya

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Meditsinskaya, 35, 3 -11. Yamamoto M, Komura K., & Sakanoue M. (1983). 241Am and plutonium in Japanese rice-field surface soils. J. Radiat.Res., 24, 237-249. Yamamoto M, Yamauchi Y., Chatani K., Igarashi S., Komura K., & Ueno K. (1990). Fallout 237Np, Pu isotopes and 241Am in lake and sea sediments from the coastal area of the Sea of Japan. Radiochim. Acta, 51, 85-95.

Yamamoto M.s Tsukatani T., & Katayama Y. (1996a). Residual radioactivity in the soil of the Semipalatinsk nuclear test site in the fomer USSR. Health Phys., 71, 142-148. Yamamoto M., Tsumura A., Katayama Y., & Tsukatani T. (1996b). Plutonium isotopic composition in soil from the former Semipalatinsk nuclear test site. Radiochim. Acta, 72,209-215. Yamamoto M., Tsumura A., & Tsukatani T. (1998). Current levels of Pu isotopes and 137Cs at the former Soviet Union1 s Semipalatinsk nuclear test site. Radiochim. Acta, 81, 21-28. Yamamoto ML, Hoshi ML, Takada J., Sekerbaev A. Kh., & Gusev B.I. (1999). Pu isotopes and I37Cs in the surrounding areas of the former Soviet Union's Semipalatinsknucleartest site. /. Radioanal.Nucl. Chem., 142 (in press).

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Fig. 1 Full view of the Semipalatinsk Neclear Test Site (SNTS)

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Fig. 5 Accumulated levels (Bq/m2 ) of I37Cs for surface soil (10 cm in depth) and core

soil (ca. 30 cm in depth) from several sites outside the SNTS territory. 2 239?240Pu inventory (Bq/m )

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Fig. 7 The Plot of 239>240Pu inventories vs. 137Cs inventories for the soil samples . The slope line is the activity ratio of 239>240Pu/137Cs found for global fallout. 3.0x10" >4 ' 4 , 10 10 10 : F4 Css 8660 Bq/m2 W1 W2 2 2 2 '• Cs» 8330 BqAn2 C*s 8080 Bq/m Pu= 323 Bq/m Cs= 3440 Bq/m 2 Pu= 375 Bq/m2 30400 Bq/m2 Pu=1800Bq/m 3. 3. 3. 3. ffl 10 10 10 1 10

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10 1O41 10 10 N1 Cs» 2130 Bq/m2 SP1 SO W3 W8 2 2 I CM 2 C»= 3710 Bq/m2 . Cs* 4420 Bq/m Pu= 85.8 Bq/m I Css 2690 Bq/m 2 to 2 2 Pu= 365 Bq/m Pu=. 187 Bq/m P-ja 204 Bq/m § 3. .3. 3. ,3. I 10 10 o I 239,240pu ©

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239>240 Fig. 8 Typical depth profies of Pu and '""C137r s concentrations for core soil samples from the areas within and outside the SNTS territory. JAERI-Conf 2000-016

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Atomic ratio Sample 240^ 239Pu Remarks

1st Exp Site 0.036 ± 0.001 Surface soil sampled near the hypocenter of the first Soviet (This work) nuclear explosion on August 29,1949, Surface soil sampled around the top of the bank of crater Balapan 0,067 ± 0.001 (This work) (Shagan River Site) which was formed by the underground nuclear explosion on January 15,1965. Nevada Test Site soil 0.054-0.063 (Ave.0.05) USA: Nuclear Test Site 1 Rocky Flat Plant 0.051 Weapons-grade Pu fabricated at the Rocky Flat Plant2 I 3 9 Bikini soil 0.338 ±0.051 Bikini Atoll: Thermonuclear atomic bomb (Bravo: March 1,1954) Bontenchiku 0.318 ±0.023 Hemp-palm leaves: Fishing gear used by the Fifth Fukuryo-Maru 3 (Lucky Dragon: March 1,1954) i Nagasaki soil 0.042 ± 0.014 Nishiyama area in Nagasaki: Pu atomic Bomb ( August 9,1945) 3 o Thule sediment 0.058 ± 0.008 Greenland: Weapons-grade Pu due to accidental crash (January 1968) ofaB-52bomber3 Surface sediment from 24 intertidal sites around Irish Sea : Release Irish Sea sediment 0.19-0.22 (Ave.0.20) of Pu into the Irish Sea from the Sellafield nuclear fuel reprocessing plant, UK4 M. Kanmuri soil 0.18 ± 0.03 Surface soil (May 1978): Global fallout Pu 3

1Hardy,1976; 2Krey and Hardy, 1970; 3Komura etal, 1984; 4Kim, 1990. Table 2 Plutonium isotopic composition in soil from the 1st Exp Site and Balapan

Isotope Activity (Bq/g) Activity relative to 239-240Pu Atom relative to 239Pu 1st Exp Site 5 238pu 0.404 ± 0.028 0.0145 ± 0.001 (5.91 ± 0.44) XI 0~ 239pu 24.6 ± 0.8 0.88-±.0.03 1.0 240pu 3.35 ± 0.27 0.12 ± 0.01 0.036 ± 0.001 239, 240pu 27.9 ± 0.4 1.0 4 24,pu 4.83 ± 0.14 0.173 ± 0.005 (1.16±O.O5)X1O- 3 6 5 eV 242pu (7.5 ± 0.6) X10" (2.7 ±0.2)X10~ (4.8 ±0.4)Xl0- | Balapaa o "8Pu 3.96 ± 0.08 0.447 ± 0.006 (2.01 ± 0.04) X10"3 o3, 239p to u 7.08 ± 0.13 0.80 ± 0.01 1.0 o 240pu 1.77 ± 0.05 0.20 ± 0.01 0.067 ± 0.001 8 239. 240pu 8.85 ± 0.12 1.0 1 4 h-O* 24tpu 10.8 ± 0.3 1.22 ± 0.03 (8.99 ± 0.26) X10" J 4 242pu (1.3 ± 0.2) X10-" (1.5 ±0.3)X10~ (2.9 ±O.5)X1O'

All are as of the date of sampling (October 7, 1994 for the 1st Exp Site soil and October 8, 1994 for the Bolapan soil). Table 3 Global and SNTS deposition of ^'^Pu and ™Cs based on the vaPvfi9?a atomic ratio method

Inventory Atomic ratio Ave. Atomic ratio a9J4OPu l37Cs Sample Cs* Pub Cs Pu Pu-240 Pu-240 (Pu)G (Pu)W (Pu)W (Cs)G (Cs)W (Cs)W Pu-239 Pu-239 Y Total Total (Bq/m2) (Bq/m2) (%) (%) (Bq/m2) (Bq/m2) (%) (Bq/m2) (Bq/m2) (%)

Ul-3 4883 215.4 S 91.4 53.3 0.145 ±0.004* 0.0971 1.05 105.0 110.4 51.2 3571 1311 26.9 R 8.6 46.7 0.042 + 0.002

U2-1 3162 150.0 S 91.9 51.3 0.137 ±0.009 0.0906 1.26 66.2 83.8 55.8 2252 909 28.8 R 8.1 48.7 0.042 ±0.002 Con f S U7-4 2851 164.3 S 95.0 55.5 0.096 ±0.009 0.0719 2.51 46.9 117.5 71.5 1594 1258 44.1

T R 5.0 44.5 0.042 ±0.003 2000-01 6

U9-2 3611 225.2 S 94.0 61.5 0.091 ±0.009 0.0738 2.65 61.8 163.4 72.6 2100 1511 41.9 R 6.0 38.5 0.046 ±0.002

U15-3 6124 436.5 S 90.5 52.3 0.090 ±0.002 0.0658 2.96 110.2 326.3 74.8 3747 2378 38.8 R 9.5 47.7 0.039 ±0.002

U18-1 3653 194.1 S 93.8 58.4 0.093 ±0.002 0.0669 2.09 62.9 131.2 67.6 2138 1515 41.5 R 6.2 41.6 0.031 ±0.004

S and R mean the soluble and insoluble fractions by leaching from soil with HNO3 and H^Oj, respectively. ': l37Cs, b: *"*fti ': One standard deviation of replicate measurements (n=4) in final solution taken from one sample. JAERI-Conf 2000-016

Appendix 1. Geological position (by GPS) of sampling sites within and outside the SNTS territory

Site No. Sampling Position Remarks No. of surface No. of core date (By GPS) soil (0-10 cm)* soil (0-30 cm) F6 Oct. 26 50' 2SATH 77" 4974-E Bare din, ca. 1 km SE from GZ**, vegetation cover ca.50% 2 F5 Oct. 26 50* 2GST N 77* 4S'45"E Bare dirt, ca.1.5 km NE from GZ,vegetation cover ca.50% 4 1 F4 Oct. 26 50* 28WN 77* 5r40"E Bare dirt, ca. 5 km NE from GZ .vegetation cover ca.50% 5 1 F3 Oct. 26 50' 31'27'N 77* 58'17-E Bare din, ca.15 km NE from GZ .vegetation cover ca.50% 3 1 F2 Oct. 26 so- 3T03"N 78" 13'41-E Bare dirt, ca.36 km NE from GZ km.vegciation cover ca.50% 3 1 Fl Oct. 26 so* 44XH-N 78* 29'48'E Bare din, near gate of main road from Kurchatov headquarters to 3 1 GZ, ca. 59 km NE from GZ, vegetation cover ca.20%.

Kl Oct26 50" 4T52'N 78" 27WE Kurchatov, ca. 60 km NE from GZ. courtyard of building, vegetation cover 10-20% AKI OcL26 50* 4T5STN 78" 27'40"E Akzhar (ca. 60 km from GZ), in the middle of town over din road,. 1 courtyard of a certain house, vegitation cover 10-20% UC2 Oct26 so- 4T51-N 78" 2T16"E Akzhar, edge of town in pasture, vegetation cover 30% 1 Al OCL22 so' 3T50'N 78' 30'19"E Bare dirt, ca. 50 km E from GZ, vegetation cover ca.50% s 1 A2 Oct. 22 SO* 2334-N 78* 29fj3"E Bare dirt, ca JO km S from Al along road.vegetation cover ca.50% 5 I A3 Oct22 50* 17WN 78' 2574"E Bare dirt, ca.40 km S from A1 along road.vegetation cover ca.50% 5 1 A4 Oct. 22 50* 06"15"N 78" 41'46-E Bare dirt, ca.80 km from Al along road,vegetation cover ca.50% 5 I

D5 Oct25 50* 1S"56~N 78* 21'43'E Bare dirt, ca. 45 2cm from GZ, vegetation cover ca.50% 3 I D4 OCL2S 50" 0S-5S- N 78* 1070"E Bare dirt, ca. 45 km from GZ, vegetation cover ca.50% 3 1 D3 OCL25 49* 56-56'N 77" 5934"E Bare dirt, ca. 5S km S from GZ, vegetation cover ca.50% 3 1 D2 OCL25 49' 4T53-N 77" 59'49"E ML Degelen, in coppice, ca. 72 km S from GZ 1 Dl OCL25 49* 46"59-N 78" 02t>8"E ML Degelen, about 75 km S from GZ, vegetation cover ca. 100% 3 1

B2 OCL23 49* 5T54-N 78" 50'53"E Bare dirt, ca.95 km from GZ, vegitation cover ca. 50% 3 1 Bl OCL23 49" 4TI6-N 78* 4272"E Bare dirt, ca.96 km SE from GZ, vegitation cover ca. 50% 3 1 Cl Oct. 24 49' 4230-N 78* 41'11-E In pasture, ca.100 km SE from GZ, vegitation cover ca. 50% 1

SI Oct. 23 49" 36TJ5-N 78' 4471 "E Sarzhal (110-115 km SE from GZ), in th middle of lown, 5 1 bv the side of a certain bouse 1 S2 OCL23 49" 35-S6-N 78' 44 02"E Sarzhal, in In middle of lown, by the side of a certain house 5 S3 OCL23 49' 35-46-N 78" 4415"E Sarzhal, in Ih middle of town, by the gate of a certain house 3 S4 OCL23 49* 3S36V 78' MVTE Sarzhal, in th middle of town, courtyard of a certain house 3 S5 OCL23 49* 3530"N 78' 44'12"E Sarzhal, ca. 0.2 km south of town in pasture (ca.50% cover) 3 1 S6 Oct. 23 49* 36"02"N 78' 45'14-E Sarzhal. ca. 0.3 km east of lown in pasture (ca .80% cover) 3 2 S7 OCL23 49* 3ff3S"N 78* 44'14"E Sarzhal. ca. 0.3 km north of lown in pasture (ca. 50% cover) 3 • Area per one soil sample collected =1734 cm'. "•GZ = ground zero (50* 26-U"N,77' 48'39" E) for the fust nuclear explosion site where we were escorted.

Site Lab. Sampling Position Remarks Dose rate4 No. of surface No. of core No. ID date (GPS) ((lSy/h) soil (0-10 cm)** soil (0-30 cm)* Wl SP04 10/3/96 50 36W •N 78 51'45"E Izvyestka, near Pechika, sand 0.06 3 1 W2 SP01 10/3/96 50" 42'Or'N 79* 07'40"E Mostik, in forest 0.06 5 2 W3 SP05 10/3/96 50' 36W 'N 79' 12'48"E Tchagan, near railway station, vegetation cover ca. 0% 0.08 5 1 W4 SP02 10/3/96 50" 3937"N 79' 19WE Doron, bare dirt near Charch 0.0» 5 W5 SPO3 10/3/96 50' 39'40" N 79' 1927"E Doron, on side of river in pasture.vegitation cover ca. 50% 0.06 5 1 - W6 SPIO 9/24/97 50- 44'39 'N 79* 18'4S"E In forest, on side of the road connecting Doron and Semipalatinsk City 0.06 5 1 VV7 SPI1 9/24/97 50* 4977"'N 79' 2S36"E In forest, on side of the road connecting Doron and Semipalatinsk City 5 1 W8 SPI2 9/24/97 50" 4478" N 79' 38-3PE In forest, on side of the road connecting Doron and Semipalatinsk City 5 1 W9 SP13 9/24/97 50" 38S3" N 79* 53'36"E In forest, on side of the road connecting Doron and Semipalatinsk City 0.05 5 1

ZN1 SP07 10/3/96 50* 0423"N. 79* 35'13"E Znamenka, in the middle of town, courtyard of a certain house 3 1

SP1 SP06 10/3/96 50" 24'30"N 80* 15'35"E Semipalatinsk City, courtyard of a certain house 0.10 5 1 SP2 SPI9 9/24/97 50" 23"02"N 80* 17TH"E Semipalatinsk City, in field, vegiation cover ca.50% 5 2

Nl SP20 9/24/97 51" 03'04"N 81* 0074-E Kolosten, in pasture, vegetation cover .ca.50% 0.07 5 I N2 SP21 9/24/97 51" 02'05-N 80* 58'57"E Kolosleri, in pasture, vegetation cover ca.50% 5 1 N3 SP22 9/24/97 50' 43'01"N 80* 56'37"E In pasture, on side of the road connecting Kolosleri and Semipalatinsk City 5 I N4 SP24 9/24/97 50* 4325" N 80' 54'H"E In forest, on side of the road connecting Kolosteri and Semipalatinsk City 5 1 N5 SP25 9/24/97 50' 3872" N 80" 34'37"E In pasture, on side of the road connecting Kolosleri and Semipalatinsk Cil 0.06 5 1 N6 SPM 9/24/97 50* 28'40" N 80' 17'39"E In foreseen side of the road connecting Kolosteri and Semipalatinsk City 5 1

•: Exposure dose rate (potable type survey meter, PDR-101: Csl detector, Aloka Co., Ltd, Tokyo) in the air at about 1 m level above ground where soil sample was collected. ••: Area of soil collected (17.34 cm1)

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Appendix II. Geological position (by GPS) of sampling sites around the Ust'-Kamenogorsk district

Site Lab. Sampling Position Remarks No. of surface No. of core No. ID date (By GPS) soil (0-10 cm)' soil (0-30 cm)' U-l 97SI 10/3/97 50' 19.71'N 80" 47.01'E In pasture, on side of Ihe load connecting Usi'-Kamenogorusk City 3 and Scmipalalinsk City U-2 97S2 10/3/97 50' 03.86'N 81' 09.73'E In psturc. on side of the road connecting Usl'-Kamenogoru.sk City 3 and Scmipalatinsk City U-3 97S3 100/97 50* 07.84'N 81" 38.91'E Bare din, on side of the road connecting Usf-Kamenogorusk City 4 and Scmipalatinsk City U-4 97S4 10/3/97 50' 08.25'N 82' 09.10'E In pasture, on side of the road connecting Usi'-Kamcnogorusk City 3 and Scmipalatinsk City U-S S7S! 10/4/97 49" 53.98'N 82* 42.74'E Ust'-Kamcnogorusk. in bare din on side of a petroleum plant 3 U-6 97S10 "10/4/97 50* 00.95'N 82' 32.85'E Ust'-Kamcnogorusk. in bare din on side of a brickyard 3 U-7 97SII 10/5/97 49* 57.07'N 82' 37.40'E Usc'-Kamcnogorusk. a public park of town 5 U-8 V7SI6 10/5/97 50' 01.59'N 82" 30.05'E Ust'-Kamcnogorusk, in bare dirt on side of an airport 3 U-9 97517 10/5/97 50" OUO'N 82" 45.65'E Usi'-K2mcnojorusk,a square of a certain company 3 U-10 97S18 10/6/97 50* 17.95'N 82" 36.26'E Suburbs of Usl'-Kamenogorusk, in bare din on side of the road, ca 168 km 3 from the Kazkh Scientific Research Institute for RidiaU'on Medicine (KIR) U-ll 97SI9 10/6/97 50* 29.05'N 82" 16.51'E In bare dirt on side of Ihe road, ca.144 km from KIR 3 U-12 97S2O 10/6/97 50' 36.70'N 81* 56.3<5'E In bare din on side of the road, ca.122 km from KIR 3 U-13 97S22 10/6/97 50" 29.34'N 81' 53.58'E In bare din on side of the road, ca. 117 lem from KIR 3 U-14 97SJ3 10/6/97 50' 13.96'N 82* 06.52'E In bare din on side of the road, ca.134 km from KIR 3 U-J5 97S24 10/6/97 50' 11.45'N 82" 16.98'E In bare djn on side of the road. ca. 147 km from KIR _ 3 U-16 97S2J 10/7/97 so- 33.73'N 81* 40.42'E In bare din on side of the road. ca. 103 km from KIR 3 U-17 97S26 1 On/97 so' 38.89'N 81" 06.00'E In bare din on side of the road, ca.66 km from KIR 3 U-18 V7S27 10/7/97 50' 43.32'N 80" 54.28'E In forest on side of the road, ca.58 km from KIR 3 U-19 97S7.J 10/7/97 SO' 39.1 l'N 80' 39.0 l'E In rorest on side of the road, ca.39 km from KIR 3 U-20 Scnup. 100/97 50' 24.47'N 80" 14.93'E The Lenin part of Semipalalinsk City 3

•: Area of soil collected (17.34 cm1)

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