|Autoren des Beitrags|
|Titel des Beitrags||Long-term distribution and migration of Cs-137 in a small lake ecosystem with organic-rich catchment: A case study of Lake Vorsee (Southern Germany)|
|Titel veröffentlicht in ...||Journal of Environmental Radioactivity|
|Erscheinungsjahr||2019||Seite (von - bis)||89-103|
|ISBN||0265-931X||Publikations-Art||Peer-Reviewed Article||Band/Jahrgang/Volume||2019, Volume 198|
|Abstract :||In the shallow eutrophic Lake Vorsee with an organic-rich catchment the 137Cs activity concentration in water samples (n = 250) and different fish species (n = 631) was determined for a period of 30 years starting soon after the Chernobyl fallout. To understand the distribution and migration of 137Cs in the ecosystem of Lake Vorsee, also the 137Cs inventory in soils of the catchment area, in sediments, in suspended matter, in water plants, as well as its vertical distribution in soils and sediments were studied.
The time dependency of the 137Cs activity concentration in water and fish was modelled with a compartment model (AQUASCOPE) as well as with the sum of two exponential functions. Results for effective half-lives of 137Cs in water are T_"eff1" =1.2 a and T_"eff2" = 7.2 a; for small cyprinidae T_"eff1" = 0.6 a and T_"eff2" =8.9 a; and for pike T_"eff1" = 1.4 a and T_"eff2" = 12.1 a. The vertical distribution of 137Cs activity concentration in soils was described by a partial differential equation (diffusion constant D = (1.05 ± 1.16) cm2 a-1 and convection speed v = (0.14 ± 0.07) cm a-1) and its distribution in sediments by a system of two coupled partial differential equations (fixation rate f = 2.0 d-1; distribution coefficient K_"d" ^"ex" = (543 ± 140) L kg-1; sedimentation rate R_"S" = (0.030 ± 0.010) g(cm2 a)-1; bioturbation constant D_"bio" , decreasing linearly with depth with D_"bioabs" = (3.3 ± 1.0) cm2 a-1 at the surface).
According to the extended AQUASCOPE model, the following fractions of the total 137Cs inventory were found in the different compartments of the lake ecosystem in 2016: 9.0∙10‐1 in soils of the catchment area, 1.0∙10‐1 in sediments, 5.5∙10‐5 in water, 1.5∙10‐5 in suspended matter, 1.3∙10‐5 in watermilfoil, and 1.6∙10‐6 in fish.
Bachelorstudiengang Physikalische Technik
Masterstudiengang Umwelt- und Verfahrenstechnik
Fakultät Technologie und Management
Institut für Angewandte Forschung (IAF)
Schwerpunkt Energie und Umwelt (IAF)
Bachelorstudiengang Energie- und Umwelttechnik
Dr. rer. nat.
Radioökologische Studien und Untersuchungen