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  • 1995-1999  (12)
Source
Material
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Association of fallout 239+240Pu and 241Am with various soil components in successive layers of a grassland soil (1995)
    s.l. : American Chemical Society
    Environmental science & technology 29 (1995), S. 2513-2518 
    Details
    ISSN: 1520-5851
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/es00010a006
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Calculation of the Helfferich Number to Identify the Rate-Controlling Step of Ion Exchange for a Batch Process (1995)
    s.l. : American Chemical Society
    Industrial & engineering chemistry research 34 (1995), S. 2584-2587 
    Details
    ISSN: 1520-5045
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ie00047a005
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Unexpectedly slow decrease of chernobyl-derived radiocesium in air and deposition in Bavaria/Germany (1995)
    Springer
    Naturwissenschaften 82 (1995), S. 417-420 
    Details
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01133675
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Unexpectedly Slow Decrease of Chernobyl-Derived Radiocesium in Air and Deposition in Bavaria/Germany (1995)
    Springer
    Naturwissenschaften 82 (1995), S. 417-420 
    Details
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01133675
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Vertical Migration of Chernobyl-Derived Radiocesium in Bavarian Grassland Soils (1997)
    Springer
    Naturwissenschaften 84 (1997), S. 204-207 
    Details
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001140050379
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    In situ γ-spectrometry several years after deposition of radiocesium (1996)
    Springer
    Radiation and environmental biophysics 35 (1996), S. 297-303 
    Details
    ISSN: 1432-2099
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Several years after the deposition of fallout radiocesium, the maximal activity of this radionuclide will not remain at the soil surface but be found rather in deeper layers. In order to estimate the total radiocesium contamination of a large area and the resulting γ-dose rate by in-situ spectrometry, it is necessary to approximate the vertical distribution of this radionuclide by an analytical function. Observations at ten undisturbed grassland soils in Bavaria, Germany, show that the resulting depth distributions can be approximated closely by a three-parameter Lorentz function. This function characterises the observed distributions in all three critical sections, i.e. the surface layer, the distribution around the maximal concentration, and the tail at greater depth. It is also shown that the observed total activity per unit area of the soil due to 137Cs agrees very well with the corresponding value obtained from the integrated Lorentz function. The two coefficients of the Lorentz function, which characterise the location (depth) and width of the maximum in the activity distribution, are shown to be correlated. In part II of this study, it will be shown how the parameters of the Lorentz function can also be obtained by in-situ γ-ray spectrometry. As a result, it is possible to use in-situ γ-ray spectrometry to obtain the total 137Cs activity per unit area also for sites where the vertical distribution of this radionuclide in the soil is no longer exponential.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004110050043
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    Association of Chernobyl-derived 239+240Pu, 241Am, 90Sr and 137Cs with different molecular size fractions of organic matter in the soil solution of two grassland soils (1998)
    Springer
    Radiation and environmental biophysics 37 (1998), S. 195-200 
    Details
    ISSN: 1432-2099
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Radiocesium is normally bound only rather weakly and unspecifically by humic substances, in contrast to the actinides Pu and Am. Recently, however, it was observed that fallout 137Cs in the soil solution from an Of-horizon of a podzol forest soil (slightly decomposed plant material) was associated essentially only with one single size fraction of the humic substances. In deeper soil layers with well humified material (AOh-horizon), radiocesium was associated with all size fractions of the dissolved organic matter (DOM). To examine whether this unexpected behaviour is also observable for DOM isolated from other soils, we determined the association of fallout 137Cs,90Sr,238Pu, 239+240Pu and 241Am with various size fractions of DOM from in situ soil solutions isolated from two layers (0–2 cm and 2–5 cm) of two grassland soils (a soddy podzolic soil and a peat soil) within the 10 km zone of the nuclear reactor at Chernobyl (Ukraine). The four size fractions of DOM as obtained by gel filtration of the soil solution were (mean nominal molecular weight in daltons): fraction I: ≥2000, fraction II: 1300; fraction III: 560, fraction IV: inorganic compounds. The results for the well humified DOM (humus accumulation horizon of podzol, deeper layer of peat soil) showed that Pu and Am are essentially associated with the high molecular weight fractions, while Sr is present only in the `inorganic' fraction. Radiocesium is found in all the size fractions separated. A quite similar pattern was also found for Pu, Am, and Sr in the soil solution from only slightly decomposed plant material (0–2 cm of peat soil), but not for radiocesium. This radionuclide was again essentially only observable in one single low molecular weight fraction of DOM. The above results thus support our recent observations in the different horizons of a forest podzol mentioned above, even though no reason for the different binding of radiocesium by well humified soil organic matter and by only slightly decomposed plant material can be given at present. The data demonstrate, however, that information on only the total amount of a radionuclide in the soil solution will not be sufficient to interpret or predict its fate adequately in the soil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004110050117
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    Paper (German National Licenses)
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  • 8
    Electronic Resource
    Electronic Resource
    Association of fallout radiocesium with soil constituents: effect of sterilization of forest soils by fumigation with chloroform (1996)
    Springer
    Radiation and environmental biophysics 35 (1996), S. 229-233 
    Details
    ISSN: 1432-2099
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract The effect of soil sterilization by chloroform fumigation on the release of fallout radiocesium incorporated in the fungal biomass of the organic layer of two forest soils was investigated by applying a sequential extraction procedure for radiocesium. The amount of the biomass in all soil samples was estimated by determination of the dissolved organic carbon (DOC) before and after fumigation, and qualitatively also by the ergosterol test. The five fractions obtained by sequential extraction (modified Tessier procedure) were: (I) easily exchangeable, (II) bound to oxides, (III) bound to organic matter, (IV) persistently bound, (V) residual. For the samples from the soil under spruce trees, no significant effects were apparent in any of these five fractions as a result of chloroform fumigation, indicating that the amount of radiocesium in the biomass of this soil was obviously negligibly small compared with the radiocesium associated with other soil constituents. The results obtained for the soil samples from the beech stand, however, reveal that the destruction of the biomass by chloroform fumigation modified considerably the extent of the association (i.e., binding) of radiocesium with the various other soil constituents (especially the clay minerals). As a result of this rapid redistribution of radiocesium released by the fungal biomass, it is not possible, in general, to attribute the observed increase of radiocesium in fraction I (easily exchangeable) after soil sterilization quantitatively to radiocesium released by the biomass. A reliable method to determine the amount of radiocesium incorporated in the fungal biomass of the soil samples which also contain clay minerals has, therefore, still to be developed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004110050034
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    Paper (German National Licenses)
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  • 9
    Electronic Resource
    Electronic Resource
    137Cs mobility in soils and its long-term effect on the external radiation exposure (1997)
    Springer
    Radiation and environmental biophysics 36 (1997), S. 31-37 
    Details
    ISSN: 1432-2099
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract To predict the external gamma-dose rate of Chernobyl-derived 137Cs for a period of about 100 years after its deposition, the vertical distribution of radiocesium in several meadow soils in the Chernobyl area and in Germany was determined, and the corresponding residence half-times of this radionuclide in the various soil layers were evaluated using a compartment model. The resulting residence half-times were subsequently used to calculate the vertical distribution of 137Cs in the soil as a function of time and finally to predict the external gamma-dose rates in air for these sites at various times. A regression analysis of the data obtained showed that the time dependence of the relative gamma-dose rate in air D(t) at the Chernobyl sites can be described by an exponential equation D(t) = a + b ⋅ exp(–t/c), where t is the time after deposition. For the ten German sites the best fit was obtained using the two-exponential equation D(t) = a ⋅ exp(–t/b) + c ⋅ exp(–t/d). The gamma-dose rate of 137Cs at the Chernobyl sites decreases significantly more slowly with time than at the German sites. This means that after e.g. 30 years the mean relative gamma-dose rate at the German sites will have decreased from 100% (corresponding to an infinite plane source on a smooth surface) to 9% (95% confidence interval 8%–10%), while at the sites in the Chernobyl area it will have decreased only to 21% (20%–23%). This difference is the result of the longer residence half-times of 137Cs in the soils at the Chernobyl sites. All results are compared with estimates from earlier studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004110050052
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    Paper (German National Licenses)
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  • 10
    Electronic Resource
    Electronic Resource
    Variability of water content and of depth profiles of global fallout 137Cs in grassland soils and the resulting external gamma-dose rates (1998)
    Springer
    Radiation and environmental biophysics 37 (1998), S. 27-33 
    Details
    ISSN: 1432-2099
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract 137Cs from global fallout of nuclear weapon testings in the 1950s and 1960s was determined in successive layers (0–30 cm) of eight undisturbed grassland soils in Bavaria, Germany. The maximum activity concentration was found in soil layers between 4 and 15 cm below the surface. Using the vertical distribution of the cesium activity, which varied considerably from site to site, the mean residence half-time of 137Cs from global fallout in each soil layer was evaluated with a compartment model. These values ranged from 1.0 to 6.3 years/cm. The mean residence half-time averaged over all soil layers and all sites was 2.7±1.4 years/cm and, thus, about twice the corresponding residence half-time of the Chernobyl-derived 137Cs as determined in the same soil layers (also in 1993). The dose rate of the external gamma-radiation due to 137Cs from global fallout in the soil determined from the depth distributions varied between 0.34 and 0.57 (mean: 0.45±0.07) nGy/h per kBq/m2. The effect of soil water content on the dose rate was studied by considering four states of the soil, from water content zero to complete water saturation of the total pore volume. It was shown that the difference between the dose rates at the permanent wilting point and the field capacity, which both represent the most relevant water contents of soils, was only 10% of the dose rate at the permanent wilting point for all sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004110050088
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    Paper (German National Licenses)
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