RADIOACTIVITY ASSESSMENT OF SURFACE SOIL IN THE VICINITY OF A URANIUM MINE IN MALAWI.

The activity concentrations of 238U, 232Th and 40K in the soil of areas surrounding the Kayelekera uranium mine were assessed. This study aims to provide a comprehensive profile of soil radioactivity distribution in the area surrounding the uranium mine to determine radiological hazards associated with mining and processing activities. Soil samples were analysed using gamma-ray spectrometry with a high-purity germanium detector. Mean specific activities of 238U, 232Th and 40K were 58.3 ± 3.7, 40.3 ± 0.3 and 590.9 ± 63.9 Bq kg-1, respectively. Results from this study have indicated changes in radioactivity levels of naturally occurring radioactive materials in the area surrounding the understudied mine, with certain areas close to the mine site showing elevated levels of 238U, highlighting the need for systematic and periodic monitoring.

Germanium in ginseng is low and causes no sodium and water retention or renal toxicity in the diuretic-resistant rats.

Ginseng preparations contain high concentrations of germanium (Ge), which was reported to contribute to diuretic resistance or renal failure. However, Ge content in ginseng and the influence on renal functions remain unclear. Forty rats were randomly divided into control group, low, moderate, and high Ge ginseng-treated group and observed for 25 days. Daily urine, renal functions, and serum and urine electrolytics were measured. Ge retention in the organs and renal histological changes were also evaluated. Ge content ranged from 0.007 to 0.450 µg/g in various ginseng samples. Four groups showed no difference in the daily urine output, glomerular filtration rate, urinary electrolytes excretions, 24 h-urine protein, as well as plasma and urine urea nitrogen, creatinine, osmotic pressure, and pH values. Ge did not cause any renal pathological effects in this study. No Na and water retention was detected in the ginseng-treated groups. Ge retention in various organs was found highest in spleen, followed by the kidney, liver, lung, stomach, heart, and pancreas. The total Ge contents in various ginsengs were low, and ginseng treatment did not affect renal functions or cause renal histological changes.

Primordial radioactivity ((238)U, (232)Th and (40)K) measurements for soils of Ludhiana district of Punjab, India.

The aim of the present work was to study the activity concentration and absorbed gamma dose rates due to primordial radionuclides ((238)U, (232)Th and (40)K) for the soil of different villages of Ludhiana district of Punjab, India using a high-purity germanium detector based on high resolution gamma-ray spectrometry. The average activity concentrations of (238)U, (232)Th and (40)K in the soil samples have been found to be 28.58, 50.95 and 569.59 Bq kg(-1), respectively, which gives the total gamma dose rate contribution of 68.50 nGy h(-1). To evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity, the external hazard index, the absorbed dose rate and the effective dose rate have been calculated. The calculated radium equivalent activity values are on the lower side of the recommended safe limit value of 370 Bq kg(-1) by Organization of Economic and Control Department. The calculated value of external health hazard index is lower than unity.

A review of recent developments in the speciation and location of arsenic and selenium in rice grain.

Rice is a staple food yet is a significant dietary source of inorganic arsenic, a class 1, nonthreshold carcinogen. Establishing the location and speciation of arsenic within the edible rice grain is essential for understanding the risk and for developing effective strategies to reduce grain arsenic concentrations. Conversely, selenium is an essential micronutrient and up to 1 billion people worldwide are selenium-deficient. Several studies have suggested that selenium supplementation can reduce the risk of some cancers, generating substantial interest in biofortifying rice. Knowledge of selenium location and speciation is important, because the anti-cancer effects of selenium depend on its speciation. Germanic acid is an arsenite/silicic acid analogue, and location of germanium may help elucidate the mechanisms of arsenite transport into grain. This review summarises recent discoveries in the location and speciation of arsenic, germanium, and selenium in rice grain using state-of-the-art mass spectrometry and synchrotron techniques, and illustrates both the importance of high-sensitivity and high-resolution techniques and the advantages of combining techniques in an integrated quantitative and spatial approach.

Characterisation of the PSI whole body counter by radiographic imaging.

A joint project between the Paul Scherrer Institut (PSI) and the Institute of Radiation Physics was initiated to characterise the PSI whole body counter in detail through measurements and Monte Carlo simulation. Accurate knowledge of the detector geometry is essential for reliable simulations of human body phantoms filled with known activity concentrations. Unfortunately, the technical drawings provided by the manufacturer are often not detailed enough and sometimes the specifications do not agree with the actual set-up. Therefore, the exact detector geometry and the position of the detector crystal inside the housing were determined through radiographic images. X-rays were used to analyse the structure of the detector, and (60)Co radiography was employed to measure the core of the germanium crystal. Moreover, the precise axial alignment of the detector within its housing was determined through a series of radiographic images with different incident angles. The hence obtained information enables us to optimise the Monte Carlo geometry model and to perform much more accurate and reliable simulations.

Natural radioactivity and external gamma radiation exposure at the coastal Red Sea in Egypt.

Radionuclides which present in different beach sands are sources of external exposure that contribute to the total radiation exposure of human. In this work, superficial samples of beach sand were collected from the Red Sea coastline (Ras Gharib, Hurghada, Safaga, Qusier and Marsa Alam areas) and at 20 km on Qena-Safaga road. The distribution of natural radionuclides in sand beach samples was studied by gamma spectrometry. The activity concentrations of primordial and artificial radionuclides in samples that are collected from the coastal environment of the Red Sea were 19.2 +/- 3 Bq kg(-1) for (210)Pb, 21.1 +/- 1 Bq kg(-1) for (226)Ra, 22.7 +/- 2 Bq kg(-1) for (238)U, 1.0 +/- 0.1 Bq kg(-1) for (235)U, 11.6 +/- 1 Bq kg(-1) for (228)Ra, 13.0 +/- 1 Bq kg(-1) for (228)Th, 12.4 +/- 1 Bq kg(-1) for (232)Th, 930 +/- 32 Bq kg(-1) for (40)K and 1.2 +/- 0.3 Bq kg(-1) for (137)Cs. The mean external gamma-dose rate was 62.5 +/- 3.2 nSv h(-1), 54.4 +/- 2.8 nGy h(-1) Ra equivalent activity (Ra(eq)) was 107 +/- 5.8 Bq kg(-1), 0.86 +/- 0.04 Bq kg(-1) for representative level index (I(gamma)) and effective dose rate was 0.067 +/- 0.003 mSv y(-1) in beach sand red sea, in air due to naturally occurring radionuclides.

Germanium-68 as a tracer for silicon fluxes in freshwater sediment.

The sorption of Si may decisively influence the P dynamics in surface sediment through competitive ligand exchange mechanisms. Many aspects of the process, such as the impact of Si dissolving from diatoms, are both insufficiently known and difficult to monitor by quantitative analyses due to the ubiquitousness of Si in sediment. Since the radioactive isotopes of Si have impractical half-times, the applicability of 68Ge as a tracer for Si additions in both inorganic and biogenic form to freshwater sediment (Lake Vesijärvi, Southern Finland) was studied in a 24-h laboratory experiment. The 68Ge-label was added to the sediment with either inorganic Si (940mg l(-1)) or diatoms (3.2 x 10(6) cellsl(-1)), and the distributions of the 68Ge-label and the different forms of added Si between the interstitial water and sequentially extracted, solid-phase sediment pools were critically examined. The inorganic Si addition significantly increased the amount of Si in the interstitial water and in the reversibly bound fraction, while the diatom addition had no discernible effects. The relative distribution of Si and 68Ge between the various sediment pools indicated that the first sorption phase of the added inorganic Si was similar to that reported for P. The high concentration of diatom-derived 68Ge-labelled Si in the interstitial water and in the easily soluble, reversibly bound pool indicated rapid dissolution of the added diatoms. The comparable distributions of the diatom-derived and inorganic Si-derived 68Ge-label within the studied pools indicated that the sorption of Si dissolving from diatoms in surface sediment closely resembles that of an inorganic addition of Si. Caution about the chemical speciation of the 68Ge-label is, however, advisable in sediment environments. Fractionation procedures designed for e.g. P may also be of limited use when applied to a different element, such as Si.

[Determination of six nutritional elements in Chinese herbal medicines by graphite furnace atomic absorption spectrometry].

Method for the determination of nutritional elements in three kinds of chinese traditional and herbal drugs including leaves of Ginkgo biloba L., Eucommiales, and Gynostemma pentaphyllum (Thunb.) Makino were studied. Samples were collected in middle of autumn, washed in water and dried by airing. About 0.5 g accurately weighed sample was digested with mixed acid of HNO3-HClO4 (4:1). Six kinds of elements of selenium, germanium, copper, zinc, iron and manganese in the digested solution were determined by graphite furnace atomic absorption spectrometry (GFAAS) respectively. Accuracy of employed AAS method was tested by the determination of Cu, Zn, Fe, Mn in standard material of peach leaves. The results obtained show proposed GFAAS method is simple, accuracy, rapid and practicable. The contents of Cu, Zn, Fe, Mn in these plant leaves are high. Especially Se in Ginkgo biloba L. and Ge in Gynostemma pentaphyllum (Thunb.) Makino were obviously higher than other herbal drugs. They are worth much more comprehensive utilization. The relation between concentrations of these nutritional elements and curative effect was also discussed.

[Study on certified reference material of germanium in Ganoderma lucidum].

Analytical reference material of Ge in Ganoderma lucidum is designed and prepared for accurete analysis, monitoration and evaluation in trades of farming, forestry, medicine and food hygiene for Ge. It is used in technical training, technical assessing, monitoring, data arbitrating and analytic method verifing for professional supervisors. This reference material has been certified by graphitic oven atomic absorption spectrometry, hydride spectrophotometry, polarography, chemical separation spectrophotometry, atomic fluorescence method and x-ray fluorescence method. According to Grubb's law to judge the data of each group, it is confirmed that all of seven groups certified crude data are normal distribution by checking normality D. The arithmatic mean value of all data is 0.38 microgram/g. Standard deviation is 0.08 microgram/g.

[Determination of germanium and selenium in malt powder by GFAAS].

A method for determination of germanium and selenium in malt powder has been developed by graphite furnace atomic absorption spectrometry with L'vov platform. While (Pd+Ni) and Pd were used as matrix modifiers,the ashing temperatures of Ge and Se were increased to 1400 and 1200 degrees C respectively,and the matrix inferences were removed. The characteristic masses are 31 pg Ge and 23pg Se(0.0044 A), the detection limits are 28pg Ge and 62pg Se (3 sigma), the precisions (n = 9) are 3. 7-5.6%(Ge) and 4.3-6.5% (Se) and the recoveries are among 90-105%.

[Simultaneous determination of germanium and molybdenum in mixtures by complexation with 5'-nitrosalicyfluorone and dual-wavelength standard addition spectrophotometry].

In the presence of hexadecyltrimethylammonium bromide and in a medium of 0.3-0.9mol/L sulfuric acid, germanium (IV) and molybdenum (VI) react with 2,6,7-trihydroxy-9 (2'-hydroxy-5'-nitro) phenylfluorone-3, i.e., 5'-nitrosalicyfluorone, to develop red complexes, respectively. The spectra of the two complexes overlap seriously each other, and the additivity of their absorbances is good in the wavelength range of 490-548nm. So a new method for simultaneous spectrophotometric determination of germanium and molybdenum by dual-wavelegth standard addition method has been investigated in detail. The analytical results of five standard mixtures are more accuracy than those obtained by isobestic-point dual-wavelength method. The method has been applied to the analysis of traditional chinese medicine and mineral water with satisfactory results.

Determination of aluminum and phosphorus in biological materials by reactor activation analysis using germanium as integral flux monitor and comparator.

A method for determination of aluminum and phosphorus in biological materials, based on activation in a nuclear reactor and measurement of 28Al, produced by the 27Al(n, gamma)28Al and 31P(n, alpha)28Al reactions, is described. Irradiations in the undisturbed and epicadmium spectra provide a two-equation system in order to determine the contributions of aluminum and phosphorus to the total activities. Germanium is used as an integral flux monitor and comparator, through the reactions: 74Ge(n, gamma)75Ge, 76Ge(n, gamma)77Ge, and 72Ge(n,p)72Ga.

Enhanced sensitivity for the determination of selenium by INAA.

A working analytical procedure for selenium determinations by INAA, using gamma spectrometry with a germanium well-type detector, is presented. The spectral line at 400.7 keV is employed, enhanced with the effect of energy summing in true coincidence of cascade photons. The main advantage of the method is high efficiency and reliable, interference-free results; potential drawbacks are increases in input count rate and pile-up losses, decrease in resolution, and sensitivity to errors in sample-to-detector geometry. The procedure is applied to certification analysis of reference materials, large-area biomonitoring by oak leave samples, and determination of separated proteins.

Determination of germanium in some plants and animals.

The Ge contents of plants and animals were investigated by a wet ashing procedure by hydride generation and inductively coupled plasma atomic emission spectrometry with flow injection. The analytical results obtained indicated that Ge contents widely vary in plant and animal kingdoms in the range of 8-302 ppb.