High Uranium Content Research Articles

Some biomedical applications of Balanites aegyptiaca grown naturally in radioactive area, Southeastern Desert, Egypt

Balanites aegyptiaca is a naturally grown desert plant at some radioactive places in Wadi El-Gemal area, Southeastern Desert. The aim of the present study was to highlight on the B. aegyptiaca species grown naturally at radioactive places in Wadi El-Gemal area (fruit part) on the ability of using the fruit in some biomedical application (glucose, cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol and diabetes). The investigated plant was collected from different location at Wadi El-Gemal area. The uranium content was determined previously and different concentrations from the fruit with highest uranium content were used to examine the effect of B. aegyptiaca (fruit part) on the glucose, triglycerides, total cholesterol (HDL and LDL-cholesterol) levels using experimental rats. Different analysis techniques were used in order to determine different parameters. The obtained data suggest the beneficial role of B. aegyptiaca fruit as an anti-diabetic and hypo-lipidimic agent.

Speciation of naturally-accumulated uranium in an organic-rich soil of an alpine region (Switzerland)

Very high concentrations of uranium (up to 4000 ppm) were found in a natural soil in the Dischma valley, an alpine region in the Grisons canton in Switzerland. The goal of this study was to examine the redox state and the nature of uranium binding in the soil matrix in order to understand the accumulation mechanism. Pore water profiles collected from Dischma soil revealed the establishment of anoxic conditions with increasing soil depth. A combination of chemical extraction methods and spectroscopy was applied to characterize the redox state and binding environment of uranium in the soil. Bicarbonate extraction under anoxic conditions released most of the uranium indicating that uranium occurs predominantly in the hexavalent form. Surprisingly, the uranium redox state did not vary greatly as a function of depth. X-ray absorption near edge spectroscopy (XANES), confirmed that uranium was present as a mixture of U(VI) and U(IV) with U(VI) dominating. Sequential extractions of soil samples showed that the dissolution of solid organic matter resulted in the simultaneous release of the majority of the soil uranium content (>95%). Extended X-ray absorption fine structure (EXAFS) spectroscopy also revealed that soil-associated uranium in the soil matrix was mainly octahedrally coordinated, with an average of 1.7 axial (at about 1.76 A ˚ ) and 4.6 to 5.3 equatorial oxygen atoms (at about 2.36 A ˚ ) indicating the dominance of a uranyl-like (UO2 2+ ) structure presumably mixed with some U(IV). An additional EXAFS signal (at about 3.2 A ˚ ) identified in some spectra suggested that uranium was also bound (via an oxygen atom) to a light element such as carbon, phosphorus or silicon. Gamma spectrometric measurements of soil profiles failed to identify uranium long-life daughter products in the soil which is an indication that uranium originates elsewhere and was transported to its current location by water. Finally, it was found that the release of uranium from the soil was significantly promoted at very low pH values (pH 2) and increased with increasing pH values (between pH 5 and 9).

Concentração de urânio em plantas desenvolvidas em solos agrícolas e de escombreira da área mineira da Cunha Baixa (Mangualde)

The uranium concentration and the bioco­centration capacity (BC) in several plant species (aboveground part) were evaluated and compared among species grown on soils developed on waste materials (Pinus pinaster, Cytisus striatus, Cytisus multiflo­rus) and agricultural soils (Zea mays L., Phaseolus vulgaris L., Lactuca sativa L.) from the surrounding area of Cunha Baixa mine (Mangualde). The species colonizing waste materials are well adapted to the substratum, which contains high total and available uranium concentration (118 mg kg-1 and 43 mg kg-1 , respectively). Pinus pinaster concentrated more uranium (13.9 mg kg-1) than the spe­cies of genus Cytisus. As a consequence, and also due to the effective vegetation cover these plants can contribute to the sta­bilization of mining wastes dumps. Lactuca sativa concentrated more uranium (on ave­rage, 5.37 mg kg-1 dry weight) than the other cultivated plants. None of the studied species was uranium accumulator (BC <1), even if they are growing in high-contaminated soils and irrigated with con­taminated water.

Chronology of the Obi-Rakhmat Grotto (Uzbekistan): First Results on the Dating and Problems of the Paleolithic Key Site in Central Asia

The Obi-Rakhmat Grotto is one of the key Paleolithic sites in Central Asia. Archaeological excavations have revealed 22 strata containing archaeological materials. Lithic assemblages from all cultural layers display features similar to both late Middle Paleolithic blade industries and early Upper Paleolithic complexes in Southwest Asia and the Siberian Altai Mountains; this suggests a gradual Middle-to-Upper Paleolithic transition occurred in western Central Asia. Hominid remains found at Obi-Rakhmat (layer 16) show a mixture of archaic and modern traits. Different chronometric methods (radiocarbon, optically stimulated luminescence [OSL], U-series, and electron spin resonance [ESR]) were applied to the site's deposits. It appears that 14C dates are more reliable in terms of correspondence to the general framework of the Paleolithic of Central Asia and neighboring regions, and after critical analysis and the deletion of outliers, the upper part of the site's cultural sequence can be dated between 36,000–41,400 BP (layer 7) and ∼48,800 BP (layer 14.1). The U-series dating results are less secure due to the high uranium content and the presence of detritus, which contaminates dated sediments (travertine). The OSL dating gave uniform ages for all cultural succession (∼8 m of deposits), and confirms a very rapid sedimentation rate. Results of ESR dating depend greatly on the choice of uptake model. Dates calculated for the early uptake to some extent correspond to 14C data. The linear uptake chosen by Skinner et al. (2007) makes sediments very old (about 55,000–90,000 yr ago), which contradicts 14C dates and does not correspond well to the regional archaeological context.

Airborne electromagnetic hydrocarbon mapping in Mozambique

The Inhaminga hydrocarbon exploration licence in central Mozambique sets the location for a multi-method airborne geophysical survey. The size of the Inhaminga block, spanning some 16 500 km2 from Beira to the Zambezi, limited available data and a tight exploration schedule made an airborne survey attractive for the exploration portfolio. The aim of the survey was to map hydrocarbon seepage zones based on the evidence that seepage may create resistivity, radiometric and sometimes magnetic anomalies. The survey involved a helicopter-borne time domain electromagnetic induction system (AEM) and a fixed wing magnetic gradiometer and radiometer.Our data analysis highlights an anomaly extending some tens of kilometres through the survey area along the eastern margin of the Urema Graben. The area is imaged by AEM as a shallow resistive unit below a strong surface conductor and shows high Uranium and low Potassium concentrations (normalised to mean Thorium ratios). A seismic dimming zone on a 2D seismic line crossing the area coincides with the resistivity and radiometric anomaly. The geological exploration model expects seepage to be linked to the graben fault systems and an active seep has been sampled close to the anomaly. We thus interpret this anomaly to be associated with a gas seepage zone. Further geological ground work and seismic investigations are planned to assess this lead.Airborne data has further improved the general understanding of the regional geology allowing spatial mapping of faults and other features from 2D seismic lines crossing the survey area.

Soil to plant ( Solanum tuberosum L.) radionuclide transfer in the vicinity of an old uranium mine

ABSTRACT Past uranium mining in the area of Cunha Baixa village, near Mangualde (Portugal), led to contamination of subsurface waters used for irrigation in the agricultural area of this village. To test radionuclide transfer to plants, two side-by-side parcels of land, each divided into four replicate lots, were used for experimental growth of potatoes ( Solanum tuberosum L.). One parcel of land was irrigated with water containing a high uranium concentration (13.7 Bq l −1 ) and the other was irrigated with water containing a low uranium concentration (0.3 Bq l −1 ). Agricultural procedures were controlled and radionuclide concentrations in soil and irrigation water were measured. The potato crop was collected and samples with and without peel were analysed for uranium isotopes ( 238 U, 235 U, 234 U) and uranium series ( 238 U daughters) alpha-emitting radionuclides (i.e. 230 Th, 226 Ra, 210 Po). The results show a significant uptake of radium, reaching 12.9 ± 1.2 Bq kg −1 dry weight, and a minor uptake of other radionuclides by potatoes. Radium transfer to potatoes was enhanced in the parcel of land irrigated with water containing high radium concentrations, but radionuclide concentrations in irrigation water had a minor effect on the transfer of uranium, thorium and polonium to potatoes. Radionuclides were largely accumulated in tubers9 peel and, in general, peeling removed most of the radioactivity. As radium in irrigation water was found to be accumulated in potatoes it may be transferred to man through the food chain. Therefore, this radionuclide should be monitored in agricultural zones near uranium mine areas.

Uranium concentration in drinking water samples using the SSNTDs

Uranium concentrations in the drinking water samples collected mainly from hand pumps along the Amritsar to Bathinda track are presented. Uranium concentration values in these samples show a wide range of variation depending upon different factors like source, location, depth and local geology etc. The observed uranium content in water samples has been found to be varying from 0.9 ± 0.08 to 63 ± 0.21 ppb and even the radon activity in ground water observed in our earlier survey carried out in this area has been found to be increasing from Amritsar towards Bathinda. The higher values were observed from the ground water samples particularly of the areas falling in belt from Zira to Maur towards the Haryana border. The values observed at certain locations are found to be higher than the highest recommended value of 15 ppb [1]. The high uranium concentration observed particularly in certain areas along this track can be attributed due to interaction of ground water with the soil formation of this region and the local subsurface geology of the region.

Comparative analysis of gene expression in brain, liver, skeletal muscles, and gills of zebrafish (Danio rerio) exposed to environmentally relevant waterborne uranium concentrations

The effects of waterborne uranium (U) exposure on gene expression were examined in four organs (brain, liver, skeletal muscles, and gills) of the zebrafish (Danio rerio). Adult male fish were exposed to three treatments: No added uranium (control), 23 +/- 6 microg U/L, and 130 +/- 34 microg U/L. After 3, 10, 21, and 28 d of exposure and an 8-d depuration period, gene expression and uranium bioaccumulation were analyzed. Bioaccumulation decreased significantly in liver during the depuration phase, and genes involved in detoxification, apoptotic mechanism, and immune response were strongly induced. Among these genes, abcb311, which belongs to the adenosine triphosphate (ATP)-binding cassette transporter family, was induced 4- and 24-fold in organisms previously exposed to 23 +/- 6 and 130 +/- 34 microg U/L, respectively. These results highlight the role of liver in detoxification mechanisms. In gills, at the highest uranium concentration, gpx1a, cat1, sod1, and sod2 genes were up-regulated at day 21, indicating the onset of an oxidative stress. Mitochondrial metabolism and DNA integrity also were affected, because coxI, atp5f1, and rad51 genes were up-regulated at day 21 and during the depuration phase. In skeletal muscles, coxI, atp5f1, and cat were induced at day 3, suggesting an impact on the mitochondrial metabolism and production of reactive oxygen species. In brain, glsI also was induced at day 3, suggesting a need in the glutamate synthesis involved with neuron transmission. No changes in gene expression were observed in brain and skeletal muscles at days 21 and 28, although bioaccumulation increased. During the depuration phase, uranium excretion was inefficient in brain and skeletal muscles, and expression of most of the tissue-specific genes was repressed or unchanged.

Heavy metals in the benthic animals from hydrothermal vents: Results of neutron activation analysis

A series of samples of inhabitants of hydrothermal vents were collected during the 12th cruise of R/V Akademik Mstislav Keldysh in Guaymas Basin (the Gulf of California) and the Axial Seamount area (Juan de Fuca Ridge). The concentrations of trace and heavy metals in the tissues of Ridgeia piscesae, Riftia pachyptila, and Paralvinella palmiformis were analyzed. The neutron-activation analysis revealed significantly higher concentrations of uranium in the tissues of Paralvinella palmiformis as compared to the ambient seawater. The possible reasons for such phenomenon are discussed. The data obtained by the neutron-activation method are compared with those obtained by the atomic-absorption method for the same tissues analyzed.

Natural radionuclides and trace elements in rice field soils in relation to fertilizer application: study of a chronic kidney disease area in Sri Lanka

The rising number of chronic kidney disease patients with no identifiable cause (CKD of uncertain aetiology), prevalent in some areas of the dry zone of Sri Lanka is suspected to be related to the environmental exposure to heavy metals. Agricultural soils are well recognized as being contaminated with potentially toxic metals from various forms of fertilizers and agro-chemicals, which could easily enter the human body through the food chain. The objective of this paper is to determine the content of heavy metals and activity concentration of background radionuclides such as K-40, Ra-226 and Th-232, in rice field soils. Rice farming is the most common agricultural practice in the affected region and possible heavy metal sources such as fertilizers are applied in abundance in the rice fields. Soils collected from a rice field in a non-CKD region was used for the comparison. In dry zone soils, Ca, K, Ba, Pb and Zr contents were higher and Fe, Mn, Cr, Ni and Zn contents were lower compared to that of soils from the wet zone non-CKD region. However, the activity concentration of soils was mostly the same in all samples, except for the K-40 contents of the soils, which were higher in the rice field soils compared to the undisturbed forest soils and also to the world averages. The mean U content was 3.6 mg/kg in the studied soils, although extremely high uranium contents were found in some fertilizer samples particularly in the triple superphosphates. Most uranium applied via fertilizer could contaminate the drinking water sources and even low uranium concentrations in drinking water may cause nephrotoxic effects.

Uranium Speciation in Drinking Water from Drilled Wells in Southern Finland and Its Potential Links to Health Effects

Exceptionally high concentrations of natural uranium have been found in drinking water originating from drilled wells in Southern Finland. However, no clear clinical symptoms have been observed among the exposed population. Hence a question arose as to whether uranium speciation could be one reason for the lack of significant adverse health effects. Uranium species were determined using time-resolved laser-induced fluorescence spectroscopy. We performed multi-element chemical analyses in these water samples, and predictive calculations were carried out using up-to-date thermodynamic data. The results indicated good agreement between measurements and modeling. The low toxicity of Finnish bedrockwater may be due to the predominance of two calcium-dependent species, Ca2UO2(CO3)3(aq) and CaUO2(CO3)3(2-), whose nontoxicity for cells has been described previously. This interdisciplinary study describes chemical speciation of drinking water with elevated uranium concentrations and the potential consequence on health. From these results, it appears that modeling could be used for a better understanding of uranium toxicity of drinking water in the event of contamination.

Geochemistry of redox-sensitive elements and sulfur isotopes in the high arsenic groundwater system of Datong Basin, China

High arsenic groundwater in the Quaternary aquifers of Datong Basin, northern China contain As up to 1820 µg/L and the high concentration plume is located in the slow flowing central parts of the basin. In this study we used hydrochemical data and sulfur isotope ratios of sulfate to better understand the conditions that are likely to control arsenic mobilization. Groundwater and spring samples were collected along two flow paths from the west and east margins of the basin and a third set along the basin flow path. Arsenic concentrations range from 68 to 670 µg/L in the basin and from 3.1 to 44 µg/L in the western and eastern margins. The margins have relatively oxidized waters with low contents of arsenic, relatively high proportions of As(V) among As species, and high contents of sulfate and uranium. By contrast, the central parts of the basin are reducing with high contents of arsenic in groundwater, commonly with high proportions of As(III) among As species, and low contents of sulfate and uranium. No statistical correlations were observed between arsenic and Eh, sulfate, Fe, Mn, Mo and U. While the mobility of sulfate, uranium and molybdenum is possibly controlled by the change in redox conditions as the groundwater flows towards central parts of the basin, the reducing conditions alone cannot account for the occurrence of high arsenic groundwater in the basin but it does explain the characteristics of arsenic speciation. With one exception, all the groundwaters with As(III) as the major As species have low Eh and those with As(V) have high Eh. Reductive dissolution of Fe-oxyhydroxides or reduction of As(V) are consistent with the observations, however no increase in dissolved Fe concentration was noted. Furthermore, water from the well with the highest arsenic was relatively oxidizing and contained mostly As(V). From previous work Fe-oxyhydroxides are speculated to exist as coatings rather than primary minerals. The wide range of δ 34S [SO4] values (from − 2.5 to + 36.1‰) in the basin relative to the margins (from + 8‰ to + 15‰) indicate that sulfur is undergoing redox cycling. The highly enriched values point to sulfate reduction that was probably mediated by bacteria. The presence of monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) is also evidence of microbial reactions. The depleted signatures indicate that some oxidation of depleted sulfide occurred in the basin. It must be noted that the samples with depleted sulfur isotope values have very low sulfate concentrations and therefore even a small amount of sulfide oxidation will bias the ratio. No significant correlation was observed between δ 34S [SO4] values and total arsenic contents when all the samples were considered. However, the wells in the central basin do appear to become enriched in δ 34S [SO4] as arsenic concentration increases. Although there is evidence for sulfate reduction, it is clear that sulfate reduction does not co-precipitate or sequester arsenic. The one sample with high arsenic that is oxidizing cannot be explained by oxidation of pyrite and is likely an indication that there are multiple redox zones that control arsenic speciation but not necessarily its mobilization and contradict the possibility that Fe-oxyhydroxides sorb appreciable amounts of arsenic in this study area. It is evident that this basin like other two young sedimentary basins (Huhhot and Hetao in Inner Mongolia) of northern China with high arsenic groundwater is transporting arsenic at a very slow rate. The data are consistent with the possibility that the traditional models of arsenic mobilization, namely reductive dissolution of Fe-oxyhydroxides, reduction of As(V) to more mobile As(III), and bacteria mediated reactions, are active to varying degrees. It is also likely that different processes control arsenic mobilization at different locations of the basin and more detailed studies along major flow paths upgradient of the high arsenic aquifers will shed more light on the mechanisms.

Radioactive elements in sediments and altered rocks of the Kikhpinych long-lived volcanic center

Data on the concentration of radioactive elements in mineral sediments and hydrothermally altered rocks of the long-lived Kikhpinych volcanic center are presented. High concentrations of uranium (up to 31 g/t) and thorium (up to 46 g/t) relative to the average values for the dacites of Kamchatka and the Uzon-Geyser depression are found in white kaolinite clays of mud pots and in dacites of the Yuzhnoe Kikhpinych thermal field transformed into kaolinite clays. In this field and in the Severnoe thermal field (in the crater of Staryi Kikhpinych Volcano) high values of volume radon activity (VA Rn > 1000 kBq/m3) were recorded in subsoil air. These high concentrations of uranium and thorium in fresh mineral sediments and anomalous values of VA Rn in subsoil air of hydrothermally altered rocks are considered to have resulted from the mass transfer of radioactive elements by fluid flows of the hydrothermal system.

Diagenetic and epigenetic alteration of Cretaceous to Paleogene organic-rich sedimentary successions in northwestern Jordan, typical of the western margin of the Arabian Plate

ABSTRACTFour reference sections through the calcareous-siliciclastic rocks of the Lower Cretaceous Kurnub Group and the Amman and Muwaqqar formations of the Upper Cretaceous to Paleogene Belqa Group in Jordan document the various processes of accumulation and alteration of organic matter (OM). Sections at Jerash, Sultani, Wadi Isal, and in the Kharazeh area were investigated by means of sedimentary petrography/mineralogy, organic petrography, and organic chemistry, and correlated with equivalent deposits in Syria and Egypt. The impacts of oxidation potential (Eh), acidity/basicity (pH) and temperature variations during the post-depositional alteration of these organic concentrations were assessed using x-y plots. Syngenetic Aptian-Albian coaly and organic-rich amber beds near Jerash developed in a tide-dominated delta under marginally alkaline conditions and were altered under slightly acidic conditions at temperatures of less than 100°C. Environmental analysis focused on Maastrichtian-Paleocene (?), oil shales in the Sultani area that were deposited in a small restricted basin on the continental shelf of the Neo-Tethys Ocean. Abnormally high contents of vanadium (V), phosphorus (P), zinc (Zn), and uranium (U) gave rise to yellow uranium ore minerals, phosphates and zinc sulfides and so bridge the gap between OM concentrations and those of uranium. The western part of the Arabian Peninsula is known for its uraniferous phosphorites and U-bearing calcretes. Reducing conditions during deposition of syngenetic OM in the oil shales may have shifted, in places, toward more oxidizing conditions in the course of post-depositional alteration at temperatures well below 200°C. Epigenetic fault-related concentration of OM was responsible for the Wadi Isal Aptian-Albian tar sand deposit and the oil seepage system in calcareous wall rocks of the Kharazeh Fault. The alteration of the tar sands (fluvial sandstones) is designated a high-sulfidation type (introduced aluminum sulfate minerals), whereas the oil seepage in Campanian shallow-marine carbonates is a low-sulfidation type (removal of aluminum sulfate minerals). Both alteration patterns may have implications for structure-bound base- and precious-metal deposits whose emplacement involves hydrocarbons as a carrier of metals in the mineralizing fluids. The Jordanian oil shales, tar sands, and uranium mineralization are possible sources of energy. Recent economic deals on the recovery and use of oil shales and uranium in Jordan are reviewed.

Palaeoenvironment of Seam I in the Marathousa Lignite Mine, Megalopolis Basin (Southern Greece)

The present study aims to elucidate the depositional environment of Seam I in the Megalopolis Basin, Southern Greece, using existing geological data supported by maceral and mineralogical analyses, as well as by natural radioactivity determinations. Very high pyrite and uranium contents and a very low tissue preservation index usually suggest a marine influence during deposition. In Seam I, however, these features are most probably the result of a karstic aquifer supplying the palaeomire with sulphate-rich, neutral to weakly alkaline water. The pyrite formation and the U precipitation are attributed to the anaerobic conditions, which prevailed during peat accumulation. The petrographic, mineralogical and geochemical data of the studied profile point to several changes in the surface runoff and the supply of clastic material during deposition.

Crustal melt granites and migmatites along the Himalaya: melt source, segregation, transport and granite emplacement mechanisms

ABSTRACTIndia–Asia collision resulted in crustal thickening and shortening, metamorphism and partial melting along the 2200 km-long Himalayan range. In the core of the Greater Himalaya, widespread in situ partial melting in sillimanite+K-feldspar gneisses resulted in formation of migmatites and Ms+Bt+Grt+Tur±Crd±Sil leucogranites, mainly by muscovite dehydration melting. Melting occurred at shallow depths (4–6 kbar; 15–20 km depth) in the middle crust, but not in the lower crust. 87Sr/86Sr ratios of leucogranites are very high (0·74–0·79) and heterogeneous, indicating a 100 crustal protolith. Melts were sourced from fertile muscovite-bearing pelites and quartzo-feldspathic gneisses of the Neo-Proterozoic Haimanta–Cheka Formations. Melting was induced through a combination of thermal relaxation due to crustal thickening and from high internal heat production rates within the Proterozoic source rocks in the middle crust. Himalayan granites have highly radiogenic Pb isotopes and extremely high uranium concentrations. Little or no heat was derived either from the mantle or from shear heating along thrust faults. Mid-crustal melting triggered southward ductile extrusion (channel flow) of a mid-crustal layer bounded by a crustal-scale thrust fault and shear zone (Main Central Thrust; MCT) along the base, and a low-angle ductile shear zone and normal fault (South Tibetan Detachment; STD) along the top. Multi-system thermochronology (U–Pb, Sm–Nd, 40Ar–39Ar and fission track dating) show that partial melting spanned ̃24–15 Ma and triggered mid-crustal flow between the simultaneously active shear zones of the MCT and STD. Granite melting was restricted in both time (Early Miocene) and space (middle crust) along the entire length of the Himalaya. Melts were channelled up via hydraulic fracturing into sheeted sill complexes from the underthrust Indian plate source beneath southern Tibet, and intruded for up to 100 km parallel to the foliation in the host sillimanite gneisses. Crystallisation of the leucogranites was immediately followed by rapid exhumation, cooling and enhanced erosion during the Early–Middle Miocene.

Radiogenic Isotope Fractionation as an Indication for Uranium Mobility in the Granites of El Shallal Area, West Central Sinai, Egypt

The granitic rocks at Wadi El Shallal area are categorized into metaluminous hornblende-biotite granites and peraluminous two- mica granites. The chemical analyses indicate that the two-mica granites are slightly altered and characterized by high uranium and thorium contents (averages 20.27 and 27.12 ppm, respectively). Compared to the hornblende-biotite granites, the 230 Th/ 234 U and 234 U/ 238 U activity ratios of the two-mica granites display values that depart significantly from equilibrium. The sample plots of the two granitic types are distributed in a trend reflecting more 234 U loss from the two-mica granites. Leaching experiments confirmed that the area around mineral grain boundaries are more enriched in 234 U relative to its parent 238 U as a result of α-recoil process that displaces the daughter nuclei outside the grain surface. This daughter ( 234 U) is ejected from the grain into the open spaces and therefore, subjected to leaching by fluids. The observed uranium series disequilibrium in the granitic rocks from El Shallal area reflects isotopic fractionation and a recent migration of uranium in the two-mica granites. The high uranium contents and U-Th isotopic composition of the two-mica granites fairly suggest that these rocks are probably the source for uranyl mineralization of the nearby Um Bogma Formation reflecting a history of leaching, mobilization and precipitation by meteoric and groundwater. However, more intensive investigations for uranium *Dept. Geology, Fac. Science, Ain Shams Univ., Cairo, Egypt.

New geochronological, paleoclimatological, and archaeological data from the Narmada Valley hominin locality, central India

The oldest known fossil hominin in southern Asia was recovered from Hathnora in the Narmada Basin, central India in the early 1980's. Its age and taxonomic affinities, however, have remained uncertain. Current estimates place its maximum age at >236 ka, but not likely older than the early middle Pleistocene. The calvaria, however, could be considerably younger. We report recent fieldwork at Hathnora and associated Quaternary type-sections that has provided new geological and archaeological insights. The portion of the exposed ‘Boulder Conglomerate’ within the Surajkund Formation, which forms a relict terrace and has yielded the hominin fossils, contains reworked and stylistically mixed lithic artifacts and temporally mixed fauna. Three mammalian teeth stratigraphically associated with the hominin calvaria were dated by standard electron spin resonance (ESR). Assuming an early uranium uptake (EU) model for the teeth, two samples collected from the reworked surface deposit averaged 49 ± 1 ka (83 ± 2 ka, assuming linear uptake [LU]; 196 ± 7 ka assuming recent uptake [RU]). Another sample recovered from freshly exposed, crossbedded gravels averaged 93 ± 5 ka (EU), 162 ± 8 ka (LU) or 407 ± 21 ka (RU). While linear uptake models usually provide the most accurate ages for this environment and time range, the EU ages represent the minimum possible age for fossils in the deposit. Regardless, the fossils are clearly reworked and temporally mixed. Therefore, the current data constrains the minimum possible age for the calvaria to 49 ± 1 ka, although it could have been reworked and deposited into the Hathnora deposit any time after 160 ka (given the LU uptake ages) or earlier (given the RU ages). At Hathnora, carbonaceous clay, bivalve shells, and a bovid tooth recovered from layers belonging to the overlying Baneta Formation have yielded 14C ages of 35.66 ± 2.54 cal ky BP, 24.28 ± 0.39 cal ky BP, and 13.15 ± 0.34 ky BP, respectively. Additional surveys yielded numerous lithics and fossils on the surface and within the stratigraphic sequence. At the foot of the Vindhyan Hills 2 km from the river, we recovered a typologically Early Acheulean assemblage comprised of asymmetrical bifaces, large cleavers with minimal working, trihedral picks, and flake tools in fresh condition. These tools may be the oldest Acheulean in the Narmada Valley. Several lithics recovered from the Dhansi Formation may represent the first unequivocal evidence for an early Pleistocene hominin presence in India. In situ invertebrate and vertebrate fossils, pollen, and spores indicate a warm, humid climate during the late middle Pleistocene. High uranium concentrations in the mammalian teeth indicate exposure to saline water, suggesting highly evaporative conditions in the past. Late Pleistocene sediment dated between 24.28 ± 0.39 cal ky BP and 13.15 ± 340 ky BP has yielded pollen and spores indicating cool, dry climatic conditions corresponding to Oxygen Isotope Stage 2 (OIS 2). An early Holocene palynological assemblage from the type locality at Baneta shows evidence for relatively dry conditions and a deciduous forest within the region. The Dhansi Formation provisionally replaces the Pilikarar Formation as the oldest Quaternary formation within the central Narmada Basin. The Baneta Formation, previously dated at 70 ka to 128 ka, correlates with the late Pleistocene and early Holocene. Our results highlight the need for further Quaternary geological and paleoanthropological research within the Narmada Basin, especially because dam construction threatens these deposits.

INITIAL INVESTIGATION OF 222Rn IN THE TBILISI URBAN ENVIRONMENT

Georgia has geological formations with high uranium content, and several buildings are built with local materials. This can create potentially high radon exposures. Consequently, studies to mitigate these exposures have been started. This study presents a preliminary investigation of radon in Tbilisi, the capital of Georgia. An independent radiological monitoring program in Georgia has been initiated by the Radiocarbon and Low-Level Counting Section of I. Javakhishvili Tbilisi State University with the cooperation of the Environmental Monitoring Laboratory of the Physics/Health Physics Department at Idaho State University. At this initial stage the E-PERM systems and GammaTRACER were used for the measurement of gamma exposure and radon concentrations in air and water. Measurements in Sololaki, a densely populated historic district of Tbilisi, revealed indoor radon (222Rn) concentrations of 1.5-2.5 times more than the U.S. Environmental Protection Agency action level of 148 Bq m(-3) (4 pCi L(-1)). Moreover, radon-in-air concentrations of 440 Bq m(-3) and 3,500 Bq m(-3) were observed at surface borehole openings within the residential district. Measurements of water from various tap water supplies displayed radon concentrations of 3-5 Bq L(-1) while radon concentrations in water from the hydrogeological and thermal water boreholes were 5-19 Bq L(-1). In addition, the background gamma absorbed dose rate in air ranged of 70-115 nGy h(-1) at the radon test locations throughout the Tbilisi urban environment.

New concept of designing Pu and MA containing fuel for fast reactors

New type of metal base fuel element is suggested for fast reactors. Basic approach to fuel element development – separated operations of fabricating uranium meat fuel element and introducing into it Pu or MA dioxides powder, that results in minimizing dust forming operations in fuel element fabrication. According to new fuel element design a framework fuel element having a porous uranium alloy meat is filled with standard PuO 2 powder of <50 μm fractions prepared by pyrochemical or other methods. In this way a high uranium content fuel meat metallurgically bonded to cladding forms a heat conducting framework, pores of which contain PuO 2 powder. Framework fuel element having porous meat is fabricated by capillary impregnation method with the use of Zr eutectic matrix alloys, which provides metallurgical bond between fuel and cladding and protects it from interaction. As compared to MOX fuel the new one features high thermal conductivity, higher uranium content, hence, high conversion ratio does not interact with fuel cladding and is more environmentally clean. Its principle advantage is a simple production process that is easily realized remotely, feasibility of involving high background Pu and MA isotopes into closed nuclear fuel cycle at the minimal influence on environment.