Projects / Programmes
Natural and anthropogenic gamma and beta emitters in ground waters of Slovenia
| Code |
Science |
Field |
Subfield |
| 7.00.00 |
Interdisciplinary research |
|
|
| Code |
Science |
Field |
| P220 |
Natural sciences and mathematics |
Nuclear physics |
tritij, datiranje, gama sevalci, naravna radioaktivnost, antropogeni radionuklidi, podzemne vode, hidrogeologija, hidrogeokemijski parametri
Researchers (12)
Organisations (3)
Abstract
Ground waters are one of the most important strategic sources. Good knowledge and understanding of aquifer's behavior and its properties are therefore essential for their efficient protection and sustainable utilization. Number of specific analyses which are necessary for satisfactory description of ground water is therefore very high, up to 179. Several specific chemical analyses mean a lot of money. This is one of main reasons for missing data and poor
knowledge for almost 40 % of Slovene territory. We therefore propose new methodology, which will be able to determine groundwater age and will be able to find correlations between groundwater dynamics, litology of aquifers and hydrological circumstances. The methodology should be used also as a decision-making model for the state authorities for preparation of the monitoring programmes.
Accurately determined water age is essential for vulnerability estimation of water body and indispensable information for assessments, prescribed and demanded by European water guideline WFD. Tritium dating method will be performed for water age determination. But, the time set of measurements is needed for accurate result. Data base of tritium concentrations for Slovenian aquifers still doesn't exist. If at least the first, basic sampling won't be done as soon as possible, the powerful and useful tool for determination of water age and vulnerability will be lost for ever.
Correlation between ground water dynamics, litology of aquifers and hydrogeological circumstances will be searched trough concentrations of dissolved gamma emitters. They will be treated as hydrogeological tracers. Gamma emitters enter into natural water cycle trough different pathways, so one single measurement offers several independent information. Influences of hydrogeological conditions and litological structure on appearance of radionuclides will be studied.
Aims and expected results are therefore:
1. establishment of basic, crucial and systematic data base for tritium and gamma emitters for all important Slovenian aquifers,
2. development of a new method which will enable the correlation studies of hydrogeological circumstances, groundwater dynamics, litology of aquifers and
3. accurate determination of groundwater vulnerability.
Working methods:
1. Sampling of ground waters, control surface waters and precipitations. All Slovenian territory will be covered. Basic hydrogeochemical parameters will be determined.
2. Measurements of samples by high resolution gamma ray spectrometry and liquid scintillation after electrolytic enrichment. The most sensitive and accurate methods will be performed.
3. Development and performance of new methodology for searching of correlations among gamma emitters, water age, vulnerability and groundwater dynamics, hydrological circumstances and litology of aquifers.
Significance for science
The interpretation of measurement results in the vicinity of the detection limit in gamma-ray spectrometry is not satisfactory elaborated yet. In the framework of the project we have improved the interpretation of the results by use of the Bayesian statistics and by elaboration of an empirical procedure for determination of the probability for Type I errors in radionuclide detection. A manuscript dealing with systematic influences on results near the detection limit is in preparation.
Measurements of Ra-226 near the detection limit present an additional problem because of the time variance of the spectrometer background. Two manuscripts, dealing with the radon-induced background of gamma-ray spectrometers, are sent for publication.
The methodology elaborated suffices for drinking water measurements, complying with the recommendations of the European Commission for gamma-ray emitters. For the determination of hydrogeochemical conditions in aquifers the methodology has too be improved. The concentrations of thorium isotopes, except Th-228, are below the detection limit. For these isotopes a new measurement technique is required: liquid scintillation alpha and beta counting after thorium separation and determination of its isotopes from the time dependence of both count rates.
Improvement of the method for determination of tritium content after electrolytic enrichment will enable more accurate dating of groundwater all over the world. Diminishing of measurement uncertainties will be of cruicial importance in very near future, because the amounts of tritium, released during bomb testing, practically are not detectable in the athmosphere and thereforcan't be used as a clock any more. Water age determination will be based on naturally produced tritium in the upper layers of the atmosphere, whith quantities, which are much smaller than were the quantities of antropogenic »bombing« tritium. The improvement of the method is therefore cruicial.
Significance for the country
This is the most comprehensive investigation of natural radioactivity of ground water in Slovenia till now. Systematic set of data for all most important aquifers is the indispensable basis for dating of slovenian groundwaters. Deteremination of groundwater age is cruicial for assesment of water vulnerability and sustainable management with one of the most important strategic source of the state.
Our contribution is better understanding of the state of ground waters in Slovenia, which is aimed to support strategic decisions in the field of ground water management. In addition a detailed interpretation of radionuclide concentration in ground water will be given, relating with other parameters of the aquifers.
Most important scientific results
Annual report
2008,
2009,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
Annual report
2008,
2009,
final report,
complete report on dLib.si
