137Cs in Soil and Fallout Around Zagreb (Croatia) at the Time of the Fukushima Accident

Abstract

This paper addresses the noticeable increase of 137Cs activity concentrations in soil and fallout in the area surrounding Zagreb (Croatia) that occurred at the time of the 2011 Fukushima accident. This topic is important for public health as 137Cs is highly toxic due to its long half-life of radioactive decay and chemical similarity to potassium. 137Cs concentrations in fallout were much greater than in soil, but remained present longer in the latter. While being detectable in our measurements, 137Cs did not spread through the food chain in amounts exceeding the maximum allowed level of radioactive food contamination. However, more thorough and consistent measurements need to be done in order to establish the precise activity trends of 137Cs in Zagreb soil and fallout.

Radioactivity of soil in Croatia I: naturally occurring decay chains

“…However, there are considerable variations of these quantities in the data for Europe, and our finding, therefore, does not represent an anomaly. Since 226 Ra and 210 Pb appear in the chain later than 238 U and have shorter T 1/2 , their activities were expected to be lower or equal to that of 238 U ( 16 ).…”

“…Even though soil radioactivity research has a long history, the interest in this matter has not diminished. In recent years, for instance, activity concentrations of radionuclides in soil have been studied for agricultural soil ( 4 , 5 ), in mining areas ( 6 ), close to industrial facilities ( 7 , 8 ) or deposits of radioactive matter ( 9 , 10 ), and after the Fukushima accident ( 11 ). Other studies focus on soil that is not directly affected by human activities ( 12 , 13 ) not only to asses the related radiological risk but also obtain baseline data as reference for the future.…”

“…We use maps to present our results, since this makes it easier to compare measured activity concentrations with the environmental diversity of Croatia. Detailed numerical data can be found elsewhere ( 16 ) and are also available from the authors upon request. Consequences of soil radioactivity for living organisms are discussed throughout the two papers, e.g., we identify regions where elevated concentrations of 222 Rn might be expected, those where the atmospheric deposition of its decay product 210 Pb is significant, or where 137 Cs propagation through food chains is more likely than elsewhere.…”

Measuring and modelling the radiological impact of a phosphogypsum deposition site on the surrounding environment / Mjerenje i modeliranje radiološkog utjecaja odlagališta fosfogipsa na okoliš

“…The results were compared to measurements of radioactivity in soil samples from the Zagreb region (NW Croatia) (12,13). The nearby area of the PG deposition site is used by local inhabitants for pasture (cattle and sheep).…”

The role of physics in radioecology and radiotoxicology

“…These are, first of all, isotopes of Ra and Rn, most notably those with the longest T 1/2 , that is, 226 Ra (T 1/2 =1600 years) and 222 Rn (T 1/2 =3.8 days) from the 238 U decay chain. 226 Ra is chemically similar to Ca and can substitute it both in geological formations, including soil (26), and in organic matter. Therefore, its migrations through the environment more or less follow those of Ca, Petrinec B, Šoštarić M, Babić D. The role of physics in radioecology and radiotoxicology Arh Hig Rada Toksikol 2019;70:3-13 which also applies to its uptake into living organisms.…”