Change search
ReferencesLink to record
Permanent link

Direct link
An ecosystem model of the environmental transport and fate of carbon-14 in a bay of the Baltic Sea
Stockholm University, Faculty of Science, Department of Systems Ecology.
Södertörns University College.
Stockholm University, Faculty of Science, Department of Systems Ecology.
Swedish Nuclear Fuel and Waste Management Co.
2003 (English)In: Ecological Modelling, ISSN 0304-3800, Vol. 166, no 3, 193-210 p.Article in journal (Refereed) Published
Abstract [en]

The environmental transport and fate of a hypothetical discharge of radioactive 14C from the Swedish final repository for radioactive operational waste (SFR) was investigated using an ecosystem modelling approach. It involved identification, quantification and dynamic modelling of the main flows and storages of carbon both in the physical environment and in the food web of a bay in the Baltic Sea. In the model, 14C was introduced into the food web via photosynthesising organisms. Contamination of the modelled ecosystem was assessed assuming a release of 51.3 MBq per year for 1000 years. The implications of changes of two parameters on the 14C fate were examined: route of 14C entry in the food web and water exchange. Modelling results were also used to estimate steady-state 14C-concentrations in biota, to investigate the time needed to reach steady-state and to calculate the ecological half-life of the radionuclide for the modelled compartments and the ecosystem. Since the modelled area is characterised by a fast water exchange, most of the discharged 14C was flushed out of the system (99.8%), and diluted in a much larger recipient. However, a small fraction of the discharge was assimilated by primary producers, which enabled subsequent transfer of 14C to organisms at higher trophic levels (e.g. fish, seals and humans). In general, the highest 14C-concentrations were observed in benthic plants and benthic macrograzers followed by fish and other organisms. An assumption of 14C entry into the food web via benthic primary producers was found to lead to increased concentrations in biota (especially benthic organisms) and reduced rates of water exchange were also observed to significantly increase the 14C exposure of the organisms.

Place, publisher, year, edition, pages
Elsevier , 2003. Vol. 166, no 3, 193-210 p.
Keyword [en]
Ecosystem dynamics; Ecosystem modelling; Carbon flow model; 14C; Radionuclides; Safety assessment; Baltic Sea; MATLAB/SIMULINK Article Outline
National Category
Biological Sciences
URN: urn:nbn:se:su:diva-23174DOI: 10.1016/S0304-3800(03)00135-2OAI: diva2:190514
Part of urn:nbn:se:su:diva-175Available from: 2004-05-13 Created: 2004-05-13 Last updated: 2009-12-28Bibliographically approved
In thesis
1. Radionuclides in the Baltic Sea: Ecosystem models and experiments on transport and fate
Open this publication in new window or tab >>Radionuclides in the Baltic Sea: Ecosystem models and experiments on transport and fate
2004 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Manmade radionuclides have been introduced to the environment for almost a century. The main source has been the nuclear weapons testing programmes, but accidental releases from the nuclear power production industries have also contributed. The risk to humans from potential releases from nuclear facilities is evaluated in safety assessments. Essential components of these assessments are exposure models, which estimate the transport of radionuclides in the environment, the uptake in biota, and transfer to humans. Recently, there has been a growing concern for radiological protection of the whole environment, not only humans, and a first attempt has been to employ model approaches based on stylised environments and transfer functions to biota based exclusively on bioconcentration factors. They are generally of a non-mechanistic nature and involve no knowledge of the actual processes involved, which is a severe limitation when assessing real ecosystems.

The research presented in this thesis attempts to introduce a methodology for modelling exposure of biota that is based on systems ecological theories and concepts. All presented papers concern bioaccumulation and circulation of radionuclides in coastal areas of the Baltic Sea, which is a sea surrounded by several nuclear power plants, waste repositories and reprocessing facilities. Paper I illustrates how an ecosystem model can be used to predict the fate of C-14 in a bay, and to explore the influence of uptake route and water exchange on the concentrations in biota. Due to the longevity of many radionuclides, time spans of thousands of years need to be considered in assessments of nuclear waste facilities. In Paper II, the methodological problems associated with these long timescales are discussed and a new modelling approach is proposed. An extension and generalisation of the C-14 flow model into a generic model for other radionuclides is described and tested in Paper III. This paper also explores the importance of three radionuclide specific mechanisms (plant uptake, excretion and adsorption to organic surfaces) for the concentrations in biota. In Paper IV, the bioaccumulation kinetics of three radionuclides in three key benthic species of the Baltic Sea is studied experimentally. Paper V considers remobilisation and redistribution of sediment-associated radionuclides due to biological mixing, in a microcosm study.

The findings in this thesis show both that it was possible to use an ecosystem approach to assess the exposure to biota, and that this approach can handle many of the problems identified in the use of traditional exposure models for radionuclides. To conclude, frameworks for the protection of the environment from ionising radiation would benefit from implementing methodologies based on ecologically sound principles and modelling techniques.

Place, publisher, year, edition, pages
Stockholm: Institutionen för systemekologi, 2004. 150 p.
radionuclide, baltic sea, ecosystem model, ecosystem dynamics, risk assessment, safety assessment, benthic invertebrates, bioturbation, bioaccumulation, remobilisation
National Category
urn:nbn:se:su:diva-175 (URN)91-7265-891-6 (ISBN)
Public defence
2004-06-04, Nordenskiöldsalen, Geovetenskapens hus, Svante Arrhenius väg 8 C, Stockholm, 13:00 (English)
Available from: 2004-05-13 Created: 2004-05-13 Last updated: 2009-04-22Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Kumblad, Linda
By organisation
Department of Systems Ecology
Biological Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 138 hits
ReferencesLink to record
Permanent link

Direct link