Long-term and long-range migration of radioactive fallout in a Karst system.

Details

Serval ID
serval:BIB_E312B463F053
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Long-term and long-range migration of radioactive fallout in a Karst system.
Journal
Environmental Science and Technology
Author(s)
Froidevaux P., Steinmann P., Pourcelot L.
ISSN
1520-5851 (Electronic)
ISSN-L
0013-936X
Publication state
Published
Issued date
2010
Volume
44
Number
22
Pages
8479-8484
Language
english
Abstract
Mountainous areas are often covered by little evolved soils from which deposited radionuclides can potentially leak into the vadose zone. In the Swiss Jura mountains, we observed unusual isotopic ratios of nuclear weapon test (NWTs) fallout with an apparent loss of NWTs plutonium relative to ¹³⁷Cs of Chernobyl origin in thinner soils. Here, we studied the karstic watershed of a vauclusian spring to determine the residence times of plutonium, ²⁴¹Am, and ⁹⁰Sr deposited by global fallout and their respective mobility in carbonaceous soils. The results show that ⁹⁰Sr is washed most efficiently from the watershed with a residence time of several hundred years. The estimated plutonium residence time is more than 10 times higher (in the range of 5000-10,000 years), and the ²⁴¹Am residence time is double that of plutonium. The spring water ²⁴¹Am/²³⁹+²⁴⁰Pu isotopic ratio is lower (0.12 - 0.28) than found in watershed soils (0.382 ± 0.077). Similar differences are found in aquatic mosses (²⁴¹Am/²³⁹+²⁴⁰Pu isotopic ratio 0.05-0.12), which are permanently submerged in spring waters. In contrast to plutonium, ⁹⁰Sr is leached from these mosses with 0.5M HCl, demonstrating that strontium is probably associated with calcium carbonate precipitations on the mosses. The higher plutonium to americium isotopic ratio found in the samples of spring water and mosses at the outlet of the karst shows that plutonium mobility is enhanced.
Keywords
Americium/analysis, Calcium Sulfate/chemistry, Cesium Radioisotopes/analysis, Chernobyl Nuclear Accident, Plutonium/analysis, Radiation Monitoring, Radioactive Fallout/analysis, Soil Pollutants, Radioactive/analysis, Strontium Radioisotopes/analysis
Pubmed
Web of science
Create date
16/02/2011 11:11
Last modification date
20/08/2019 16:06
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