Evaluation of factors influencing accumulation of stable Sr and Cs in lake and coastal fish. (August 2016)

• Record Type: Journal Article
• Authors: Konovalenko, L.; Bradshaw, C.; Andersson, E.; Lindqvist, D.; Kautsky, U.
• Is Part Of: Journal of environmental radioactivity. Volume 160(2016:Oct.)
• Page Start: 64
• Page End: 79
• Publication Date: 2016-08
• Subjects: Caesium -- Strontium -- Bioaccumulation -- Biomagnification -- Fish -- Concentration ratio; Radioactivity -- Periodicals; Radiation, Background -- Periodicals; Radioecology -- Periodicals; Radioactive pollution -- Periodicals; Environmental Pollutants -- Periodicals; Radioactive Pollutants -- Periodicals; Radioactivity -- Periodicals; Radioécologie -- Périodiques; Pollution radioactive -- Périodiques; Fond de rayonnement -- Périodiques; 539.752
• DOI: 10.1016/j.jenvrad.2016.04.022
• Languages: English
• ISSNs: 0265-931X

Abstract

Abstract: As a result of nuclear accidents and weapons tests, the radionuclides Cs-137 and Sr-90 are common contaminants in aquatic ecosystems. Concentration ratios (CR) based on concentrations of stable Cs and Sr in biota and media are used for the estimation of transfer of their radioisotopes for radiation dose calculations in environmental and human safety assessments. Available element-specific CRs vary by over an order of magnitude for similar organisms, thus affecting the dose estimates proportionally. The variation could be reduced if they were based on a better understanding of the influence of the underlying data and how that affects accumulation and potential biomagnification of stable Cs and Sr in aquatic organisms. For fish, relationships have been identified between water concentrations of K and CR of Cs-137, and between water concentrations of Ca and CR of Sr-90. This has not been confirmed for stable Cs and Sr in European waters. In this study, we analysed an existing dataset for stable Cs and Sr, as well as K and Ca, in four Swedish lakes and three Baltic Sea coastal areas, in order to understand the behaviour of these elements and their radioisotopes in these ecosystems. We found significant seasonal variations in the water concentrations of Cs, Sr, K and Ca, and in electrical conductivity (EC), especially in the lakes. CR values based on measurements taken at single or few time points may, therefore, be inaccurate or introduce unnecessarily large variation into risk assessments. Instead, we recommend incorporating information about the underlying variation in water concentrations into the CR calculations, for example by using the variation of the mean. The inverse relationships between fish CR Cs –[K]water and fish CR Sr –[Ca]water, confirmed that stable Cs and Sr follow the same trends as their radioisotopes. Thus, they can be used as proxies when radioisotope data are lacking. EC was also strongly correlated with K and Ca concentrations in the water and could potentially be used as a quick and cost-effective method to estimate water chemistry to obtain less variable CR. We also recommend some simple improvements to data collection that would greatly enhance our ability to understand Cs and Sr uptake by fish. Highlights: Seasonal variations in [Sr], [Ca], [Cs], [K] in water is large and affects fish CRs. There was an inverse relationship between stable Sr CR for fish and [Ca] in water. There was an inverse relationship between stable Cs CR for fish and [K] in water. Piscivorous lake fish biomagnify stable Cs but not Sr. The CR for fish of stable Sr and Cs can be used as proxies for their radioisotopes.