Literature data on numerical values obtained for the parameters of the two most popular models for simulating the migration of radionuclides in undisturbed soils have been compiled and evaluated ...statistically. Due to restrictions on the applicability of compartmental models, the convection–dispersion equation and its parameter values should be preferred. For radiocaesium, recommended values are derived for its effective convection velocity and dispersion coefficient. Data deficiencies still exist for radionuclides other than caesium and for soils of non-temperate environments.
In 2020, the International Commission on Radiation Units & Measurements ICRU has released Report 95 on “Operational Quantities for External Radiation Exposure”. This publication introduced a new ...measurand, namely ambient dose H∗, as the operational quantity for external exposure to be applied in the future replacing ambient dose equivalent H∗(10).
It should be noted that this change will make it necessary to adjust previously used constants and coefficients or at least to review them with regard to the new measurand. Therefore, this recommendation represents a significant cut in implementation of radiation protection systems. The revision of all previously valid factors makes it possible to develop a consistent data set. The combination of experience gained in the last decades with more extensive data sets (e.g. on the spectra of individual radionuclides) with comparatively large computing power allows the definition of optimized data collections serving as input for Monte Carlo methods. Therefore, this publication is intended to lay a suitable foundation consisting of dose rate constants for more than 400 radionuclides concerning the future measurand ambient dose H∗ and to indicate differences to values related to the ambient dose equivalent H∗(10) used nowadays.
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•Calculation of dose rate constants in ambient dose for more than 400 radionuclides.•Comparison of different conversion coefficients published by ISO 4037-3 as well as ICRU 95.•Comparison of numerical values of dose rate constants with discussion of differences.
This study focuses on radiocesium storage in soil microbial biomass of undisturbed alpine meadow sites and its relation to the soil-to-plant transfer. Soil and plant samples were taken in August 1999 ...from an altitude transect (800–1600
m.a.s.l.) at Gastein valley, Austria. Soil samples were subdivided into 3-cm layers for analyses of total, K
2SO
4-extractable and microbially stored
137Cs. Microbial biomass was measured by the fumigation extraction method, and fungal biomass was quantified using ergosterol as biomarker molecule. In general, the quantity of
137Cs stored in the living soil microbial biomass was relatively small. At the high-altitude meadows, showing high amounts of fungal biomass, microbially stored
137Cs amounted to 0.64
±
0.14
kBq
m
−2 which corresponds to about 1.2–2.7% of the total
137Cs soil inventory. At lower altitudes, microbial
137Cs content was distinctly smaller and in most cases not measurable at all using the fumigation extraction method. However, a positive correlation between the observed soil-to-plant aggregated transfer factor, microbially stored
137Cs and fungal biomass was found, which indicates a possible role of fungal biomass in the storage and turnover of
137Cs in soils and in the
137Cs uptake by plants.
We modeled the behavior of an Austrian alpine forest ecosystem on calcareous soils under changing climate and atmospheric nitrogen deposition scenarios. The change of nitrate leaching, emission rates ...of nitrogen compounds, and forest productivity were calculated using four process-oriented models for the periods 1998-2002 and 2048-2052. Each model reflects with high detail a segment of the ecosystem: PnET-N-DNDC (photosynthesis-evapotranspiration-nitrification-denitrification-decomposition; short-term nitrogen cycling), BROOK90 (water balance for small and homogenous forest watersheds), HYDRUS (water flux in complex and heterogenous soils), and PICUS v1.3 (forest productivity). The nitrogen balance model (NBM) combines the individual results into a comprehensive picture and extends the specific values beyond the limits of the individual models. The evaluation of the findings was outlined with TRACE, a model enabling a long-term prognosis of nitrogen cycling in annual time steps. Temperature increase and nitrogen input are influenced by various components and processes of the forest ecosystem. An increase of the temperature of 2.5 degrees C led to an enhancement of the N2O emission rates and affected the mineralization and the nitrification rates with the consequence of increased nitrate leaching into the subsoil. Enhanced nitrogen input also showed notable effects on nitrate leaching.
Inductively coupled plasma mass spectrometry (ICP‐MS) analysis was used to determine iodine and bromine concentrations in several Austrian agricultural soils. The determined iodine concentrations in ...topsoils vary between 1.1 and 5.6 mg kg—1, the arithmetic mean amounted to 3.1 mg kg—1, bromine contents are always higher than the corresponding iodine values, varying between 2.4 and 11.9 mg kg—1 with an arithmetic mean of 5.7 mg kg—1. Due to their different geological origin lime‐free soils on average contained significantly less iodine and bromine than calcareous soils. In general the observed values are supported by literature values from other countries far from the sea. A correlation analysis of results with several soil parameters resulted in positive correlations with clay content and a negative relation to sand content. In the group of calcareous soils I and Br correlated positively with organic carbon contents and exchangeable calcium.
Jod‐ und Bromgehalte Österreichischer Ackerböden und Beziehungen zu ausgewählten Bodeneigenschaften
In einer Auswahl Österreichischer landwirtschaftlich genutzter Böden wurden die Jod‐ und Bromgehalte mittels ICP‐MS (Induktiv gekoppelte Plasma‐Massenspektrometrie) bestimmt. Die Jodgehalte lagen zwischen 1,1 and 5,6 mg kg—1 (arithmetischer Mittelwert: 3,1 mg kg—1), die Bromgehalte schwankten zwischen 2,4 und 11,9 mg kg—1 (Mittel: 5,7 mg kg—1). Aufgrund des unterschiedlichen geologischen Ursprungs enthalten carbonatfreie Böden signifikant weniger Jod und Brom als Böden aus carbonathaltigen Gesteinen. Insgesamt stimmen die Ergebnisse gut mit Literaturwerten anderer Binnenländer überein. Eine Korrelationsanalyse ergab signifikante Beziehungen zwischen J und Br‐Gehalten und Ton‐ (positiv) sowie Sandgehalten (negativ). In carbonathaltigen Böden ergab sich zusätzlich eine positive Korrelation mit den Gehalten an organischem Kohlenstoff und den austauschbaren Calciumgehalten.
In the mountainous “Hohe Tauern” region of Salzburg (Austria), milk samples have been collected in a long-term montitoring programme since 1988, at eight alpine sites used for extensive, seasonal ...stock farming. For this alpine environment with its acidic soils developed on silicate bedrock, high soil-to-plant transfer factors and long-lasting
137
Cs contamination levels in milk—the main product of seasonal agriculture at elevated altitudes—are characteristic features. The decrease in
137
Cs concentration in milk measured since 1988 turned out to be best described by one or two effective half-lives. For the period from 1993 to 2007, which can be modelled with one effective half-life for all sites, effective half-lives between 3.7 and 15.0 years (ecological half-lives: 4.3–29.9 years) were obtained. The effective half-life increases with mean altitude of the investigated graze pastures, probably due to reduced migration velocities of
137
Cs and low
137
Cs half-value depths of a few centimetres in the soil.
In the mountainous 'Hohe Tauern' region of Salzburg (Austria), milk samples have been collected in a long-term montitoring programme since 1988, at eight alpine sites used for extensive, seasonal ...stock farming. For this alpine environment with its acidic soils developed on silicate bedrock, high soil-to-plant transfer factors and long-lasting super(137)Cs contamination levels in milk-the main product of seasonal agriculture at elevated altitudes-are characteristic features. The decrease in super(137)Cs concentration in milk measured since 1988 turned out to be best described by one or two effective half-lives. For the period from 1993 to 2007, which can be modelled with one effective half-life for all sites, effective half-lives between 3.7 and 15.0years (ecological half-lives: 4.3-29.9years) were obtained. The effective half-life increases with mean altitude of the investigated graze pastures, probably due to reduced migration velocities of super(137)Cs and low super(137)Cs half-value depths of a few centimetres in the soil.
In Europe, non-allophanic Andosols are linked with Hercynian basic and metabasic rocks in smoothed highlands with a cool and humid climate. We describe an Andosol–Cambisol toposequence derived from ...Variscan coarse-grained granite in Northern Austria (Bohemian Massif), where Andosols have formed on plateaus and Cambisols on steep slopes. The climate is continental, cool and humid (mean annual temperature and rainfall: 5.4 °C and 914 mm), with a 100-day mean annual period of snow cover. The forest is dominated by beech and spruce trees. Both soils are rich in organic matter and strongly acidic, but the Andosol is more strongly weathered than the Cambisol. Below the 15-cm-thick litter in the Andosol, the 38-cm-thick AB-Bw solum is dark reddish brown to strong brown, has a large C content (9.0–4.4%), and meets all the requirements of an andic horizon. In these horizons, oxalate extractable iron content (1.6–2.8% Fe
o) represents 76–84% of free iron, and is much larger than Al
o (0.8–1.5%). Both biotite and plagioclase are sources of Fe and Al. The formation of non-allophanic Andosol from granite was likely due to the combination of the following factors: cool and humid climate, large accumulation of organic matter, high infiltration rate, intense water percolation during spring thawing and significant content of weatherable minerals. As such conditions are not rare in European highlands, andic soils are probably more widespread in Europe than is currently thought.
Background:
Long-term ecological studies provide reference data for evaluating the response of ecosystems to external factors over time.
Aims:
At the Mühleggerköpfl forest research site, Austria air ...pollution, bioindication, hydrology, and biogeochemistry have been studied over 20 years. This paper reports the biogeochemical budget for nitrogen and carbon.
Methods:
The site is a Norway spruce (Picea abies) stand on limestone that intercepts air pollutants from long-range transport. As the over-mature trees have a low ability to assimilate surplus nitrogen (N) the forest is vulnerable to N saturation and the forest overall may release N into the groundwater.
Results:
Nitrate concentrations in the soil solution of the upper mineral soil indicate a high nitrification rate. Nevertheless, the nitrogen content in spruce needles barely exceeds the threshold of deficiency.
Conclusions:
Potential N-leaching from the soil is reduced by the slowly increasing N demand of the regenerating European beech (Fagus sylvatica) forest that is establishing under the spruce stand. The release of NOx is low, yet significant for the greenhouse gas balance. With respect to CO
2
emissions, the forest currently is neutral, but as warming stimulates the decomposition of soil organic matter it can turn the forest into a carbon (C) source. In addition, disturbances, such as bark beetle (Ips typographus) attacks that cause tree mortality strongly affect ecosystem dynamics and the biogeochemistry of C and N.
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