Project Black: from Forest to Sea, Gamma-ray Analysis of Sediments from the Danube River

      The second longest river in Europe along with its Delta (largest natural wetland) displays a sophisticated ecosystem with unique features which open the way for in-depth scientific research in the fields of geology, biology, ecology and many interdisciplinary subjects for which gamma-ray spectrometry is an essential technique. The Danube provides crucial data for raising awareness of the hazards induced by human activities, bringing significant contributions to improving methods and policies for environment preservation, wildlife protection and natural heritage conservation on a general basis, all of which being of great importance for science and society.

      Industrial pollution had a severe impact on air, water and soil/sediment quality. The TENORM nuclides dispersed in the atmosphere undergo dry/wet deposition, through complex sedimentation processes. Unsupported ²¹⁰Pb and anthropogenic radioelements concentration data help identifying the periods during which radionuclides and pollutants acumulated in sediment strata. Long term averaged effects are comparable, but on shorter scales, any floods or comparable events induce perturbations. Consequently, any data complementary to physical and chemical determinations must be considered for this interdisciplinary approach to nuclear and environmental science, as the scope is performing retrospective investigations and further prediction making by studying gradient modifications in spatial and time coordinates.

            We perform low background adaptative and customized analysis with high efficiency&resolution detectors and dedicated software in order to face different environmental samples: our protocols have a general structure, but different approaches for different matrices, potential inhomogeneity, variable background, low/high count rates and related issues for detection limits and coincidence summing corrections. Experimental results and Monte Carlo simulations enable hypothesis testing for homogeneity and uncertainty issues. Additional neutron activation brings precious information from initially non emitting isotopes. Timing is crucial given the half-life of our main dating reference (²¹⁰Pb): if the first sample sets from the course of the Danube are not measured quickly, the possibility of having time gradients for the beginning of the 20^th century will be lost.

      The goal is developing a reference sediment data repository for mapping and analyzing radionuclide and pollutant dynamics, in order to be able to make predictions regarding the evolution of radionuclide concentration in addition to the retrospective analysis, for which we have dedicated methods and an associated software under patenting [1]. We bring a unitary methodology mainly governed by the IAEA recommendations, from sampling to measurements and calculations, including experimental protocols, intercomparison schemes and uncertainty budget optimization, in order to grow the sediment database we started and the associated interactive map [2], which displays priorly available data [3] and our first contributions [4-6]. The consortium under construction started with four labs from Romanian Universities and R&D Institutes. Enhancing this collaboration between Danube River Basin countries is our target at EGU25.

 

References

[1] Suvaila et al., Romanian Patent State Office A100734/2024

[2] www.blackforesea.eu

[3] available on request

[4] Suvaila et al., DOI 10.1007/s13762-024-06128-z

[5] Olacel et al., DOI 10.1016/j.chphi.2022.100065

[6] Pojar et al., Nuclear Technology & Radiation Protection 39 (3), 2024