Radiocesium Distribution in Soils of Tenerife Island (Canary Islands, Spain)

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EGU21-3171, updated on 26 Sep 2021 https://doi.org/10.5194/egusphere-egu21-3171 EGU General Assembly 2021 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License.

Radiocesium distribution in soils of Tenerife Island (Canary Islands, Spain)

María López Pérez1, Pedro Ángel Salazar Carballo1,2, María Candelaria Martín Luis3, Francisco Javier Hernández1, Esperanza Liger4, José Carlos Fernández de Aldecoa1, Antonio Catalán Acosta1,2, and Elisa Gordo4 1Servicio General de Apoyo a la Investigación,Universidad de La Laguna, Spain ([email protected]) 2Departamento de Medicina Física y Farmacología, Universidad de La Laguna,Spain ( [email protected]) 3Departamento Biología Animal, Edafología y Geología, Universidad de La Laguna,Spain ([email protected]) 4Grupo de Geoquímica y Radioactividad Ambiental, Universidad de Málaga, Spain ([email protected])

Tenerife is the largest and most populated island of the Canary Islands; with a surface of 2,034 km2 and 917,841 inhabitants (in January 2019), it hosts 43% of the total population of the archipelago.

Large amounts of 137Cs, an artificial radionuclide with a half-life of 30.2 years, were released into the environment due to the nuclear weapon tests carried out from the 1950s to the 1970s and by nuclear power plant accidents, such as the Chernobyl in 1986. The most recent137 Cs release into the environment was due to the Fukushima Daiichi Nuclear Power Plant accident, following the earthquake and tsunami of 11 March 2011. Radionuclides released by this accident were measured in air filters collected in the Canary Islands despite the tremendous distance to the source (López-Pérez et al., 2013).

In this work, we provide the concentrations of 137Cs measured in 73 soil samples collected in 2013 in Tenerife. Besides, a second dataset of137 Cs concentrations recorded in 103 soil samples collected in 1991 (22 years before) have been used to provide information on the spatial and temporal variability of this anthropogenic radionuclide at this site.

In both surveys, sampling sites were randomly selected on a predefined 3x3 km sampling grid covering the whole island and superficial samples were collected from uncultivated fields. Radiometric measurements were performed by gamma spectrometry with a coaxial-type germanium detector (Canberra Industries Inc., USA). The activity concentration of137 Cs was directly measured by its gamma-ray photopeak at 661.65 KeV. The Minimum Detectable Activity was 0.08 Bq kg-1.

137Cs activity concentrations in the 1991 survey ranged from 0.08 to 100.90 Bq kg-1 and from 0.08 to 88.85 Bq kg-1 in 2013. Comparing the results of both campaigns,137 Cs activity concentrations were found to be rather similar, despite the 22 years gap between the measurements. We believe that, in addition to the137 Cs atmospheric fallout, there is an additional contribution to the inventory of this radionuclide in the soils of this island produced by the deposition of 137Cs-loaded dust particles frequently transported from the Sahara Desert as dust storms (Karlsson et al, 2008).

In terms of radiological risk, in some few locations, the contribution to the outdoor gamma absorbed dose from the137 Cs activity concentrations present in the soils were as high as 50%. Therefore, it is important to identify the various sources of this radionuclide to the studied sites in order to enhance the understanding of the radiological hazard produced by this man-made radionuclide.

References:

Karlsson L, Hernandez F, Rodríguez S, López-Pérez M, Hernandez-Armas J, Alonso-Pérez S, Cuevas, E. (2008). Using 137Cs and40 K to identify natural Saharan dust contributions to PM10 concentrations and air quality impairment in the Canary Islands. Atmospheric Environment, 42: 7034-7042

López-Pérez M, Ramos-López R, Perestelo NR, Duarte-Rodriguez X, Bustos JJ, Alonso-Pérez S, E. Cuevas, J. Hernández-Armas. (2013). Arrival of radionuclides released by the Fukushima accident to Tenerife (Canary Islands). Journal of Environmental Radioactivity, 116: 180-186