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|NKS Programme Area:||NKS-B|
|Report Title:||Natural Radioactivity in Nordic Fish and Shellfish – Summary report 2018|
|Authors:||Mari Komperød, Francisco Pinero, Kjartan Guðnason, Meerit Kämäräinen, Per Roos, Louise Kiel Jensen, Hilde Kristin Skjerdal, |
|Abstract:||Studies in several countries have identified fish and shellfish as the food group causing the largest contribution to the ingestion dose, due to relatively high levels of naturally occurring radionuclides. However, levels have been shown to vary drastically between species. The objective of the NANOD project is to fill knowledge gaps related to levels of naturally occurring radionuclides in the fish and shellfish species commonly consumed in the Nordic region, in order to enable more accurate dose assessments for seafood and the total diet in the Nordic countries.
Species-specific consumption data was collected from each of the Nordic countries. The mean total fish and shellfish consumption for adults varied from 37 to 57 g/d. There was also substantial variation in species composition among the countries.
Samples of commonly consumed fish and shellfish species from each of the Nordic countries were collected for analysis of 210Po, 210Pb, 226Ra, and 228Ra, as these radionuclides previously have been shown to be the main contributors to the ingestion dose. The results from analyses completed so far show 210Po concentrations in wild fish ranging from 0.079 to 1.9 Bq/kg, and from 0.94 to 77 Bq/kg in shellfish. Overall, preliminary results indicate higher 210Po levels in species with a 210Po-rich diet. This is in line with previous studies showing that 210Po enters the organisms primarily via ingestion. Moreover, farmed trout showed the lowest 210Po levels, likely due to a diet of plant-based feed with low 210Po content. Concentrations also varied significantly between samples of the same species. This may partly be related to geographic differences, although the direct cause of this is not apparent. Results of this and other work indicate that influences on 210Po concentrations in fish and shellfish are complex, and several factors may play a role.
Results of 226Ra and 228Ra analyses performed so far are mainly below the detection limits, but are sufficiently low to provide valuable information. Preliminary findings indicate highest level in blue mussels, with 1.1 and 1.5 Bq/kg, respectively. 210Pb and further results of 210Po, 210Pb, 226Ra, and 228Ra are expected in 2019. A better picture of variation and possible patterns among fish and shellfish may be possible remaining analyses are complete. The complete data set, further discussions and dose estimates will be presented in the 2019 Final Report, provided continued funding of the NANOD project.
Data on naturally occurring radionuclides in fish and shellfish is important not only due to the food group’s role in the Nordic diet, but also because the Nordic countries are important in the worldwide fish trade.|
|Keywords:||Gamma spectrometry, radioactive sources, activity determination, shielded sources, nuclear security|
|Publication date:||25 Jan 2019|
|Number of downloads:||41|