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Retention of radioactive particles and associated effects in the filter-feeding marine mollusc Mytilus edulis
Stockholm University, Faculty of Science, Department of Systems Ecology. (Marine Ecotoxicology)
University of Life Sciences (UMB), Norway. (Dep. of Plant- and Env. Sciences)
Stockholm University, Faculty of Science. (Marine Ecotoxicology)
University of Life Sciences (UMB), Norway . (Dep. of Plant- and Env. Sciences)
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Radioactive particles are aggregates of radioactive atoms formed by, e.g., condensation or precipitation of radionuclides or breakdown of larger radioactive materials, and can contain significant radioactivity. They have been released into the environment from nuclear weapons tests, and from accidents and effluents within the fuel nuclear cycle.

Aquatic filter feeders can be expected to take up and potentially retain radioactive particles, which could then provide concentrated localised doses to nearby tissues. Despite the high potential for accumulation and the potency of radioactive exposure, studies of the retention of radioactive particles in filter feeders are scarce. This study experimentally investigated the retention and effects of radioactive particles in the blue mussel, Mytilus edulis.

The spent fuel particles, collected in the field, comprised of a U and Al alloy containing fission products such as 137Cs and 90Sr/90Y. The particles were introduced into mussels in suspension with plankton food or through implantation under the mantle tissue. Induced effects of the particle exposure were measured using micronucleus and Comet assays on haemocytes. Of those particles introduced with food, 37.5 % were retained for 70 h, and were found in the siphons and gills, with the notable exception of one particle that was ingested, found in the stomach. Those not retained seemed to have been actively rejected by the mussels. In several cases where particles were retained or implanted, white marks suggesting necrosis were seen in the tissues near the particles; these are thought to be caused by radiation and physical irritation. The largest and most radioactive particle (estimated dose rate 3.18 ±0.06 Gy.h-1) caused the largest such mark in the mantle tissue; in this case, increased micronucleus frequency and Comet tail DNA % was also observed in the haemolymph collected from the muscle, implying that non-targeted effects of radiation were induced by the high dose particle.

The results showed that radioactive particles can potentially be retained by blue mussels and retained high activity particles can potentially induce negative effects, particularly in tissues close to such particles. Thus, current methods which are used for risk assessment that calculate “no-effect dose” estimates and are based upon the absorbed dose equivalent limit are inadequate for radioactive particle exposures. In addition, knowledge is lacking about the ecological implications of radioactive particles, for example potential recycling within a population, or trophic transfer in the food chain.

National Category
Biological Sciences
URN: urn:nbn:se:su:diva-83399OAI: diva2:575575
Available from: 2012-12-10 Created: 2012-12-10 Last updated: 2012-12-11Bibliographically approved
In thesis
1. Exploring phenomena that affect the fate and impact of radioactive materials in the blue mussel
Open this publication in new window or tab >>Exploring phenomena that affect the fate and impact of radioactive materials in the blue mussel
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Current protection of the marine environment from radiation is based largely on measuring, estimating and modelling accumulation and impact(s) of radionuclides in a few marine species. Using a relevant marine organism, this thesis focusses on investigating some poorly described phenomena that could cause deviations from predicted measurements.

Paper I investigated the biological transformation of tritium (radioactive hydrogen) into an organic compound. The resulting organically bound tritium (OBT) showed increased accumulation in mussels, unique incorporation into a key biological molecule (DNA), extended persistence in tissues, and greater toxicity than the inorganic form. Paper II demonstrated significant disparity in OBT accumulation between functionally similar microalgae species and that OBT in algae is readily transferred to a consumer.

Highly radioactive particles are a complex issue in radioecology due to their concentrated dose geometry, potentially inducing very different impacts in organisms, compared to external irradiation. Paper III developed a method to introduce radioactive particles that would facilitate their recovery, improve dose-calculation, and aid the measurement of toxicological endpoints. It also showed that such particles can be incorporated into mussel tissues, causing significant effects.

In Paper IV, hypoxia – another major ecological hazard in the marine environment – was expected to reduce radiosensitivity. The minimal observable effect from radiation prevented identification of such an interaction, and indicates drawbacks in the (otherwise sensitive) endpoints used. It appears that stressors like hypoxia may be more of a health hazard to marine organisms than environmental levels of ionising radiation.

By understanding such causes of variation in accumulation and impact, it is possible to improve risk assessment, providing more justification for regulations chosen and minimising conservatism in setting environmental standards.

Place, publisher, year, edition, pages
Stockholm: Department of Ecology, Environment and Plant Sciences, Stockholm University, 2013. 93 p.
Radioecology, ionising radiation, environmental protection, Mytilus edulis, bioaccumulation, dose-response, ecotoxicology, tritium, particle, hypoxia
National Category
Biological Systematics
Research subject
Marine Ecotoxicology
urn:nbn:se:su:diva-83404 (URN)978-91-7447-616-3 (ISBN)
Public defence
2013-01-18, DeGeersalen, Geovetenskapens hus, Svante Arrhenius väg 14, Stockholm, 13:00 (English)

At the time of doctoral defense, the following papers were not published and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.

Available from: 2012-12-27 Created: 2012-12-10 Last updated: 2013-01-02Bibliographically approved

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Jaeschke, BenedictBradshaw, Clare
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