Determining ²⁴¹Pu in environmental samples: case studies in alpine soils

Abstract

A procedure was developed for determining 241Pu activity in environmental samples. This beta emitter isotope of plutonium was measured by ultra low level liquid scintillation, after several separation and purification steps that involved the use of a highly selective extraction chromatographic resin (Eichrom-TEVA). Due to the lack of reference material for 241Pu, the method was nevertheless validated using four IAEA reference sediments with information values for 241Pu. Next, the method was used to determine the 241Pu activity in alpine soils of Switzerland and France. The 241Pu/239,240Pu and 238Pu/239,240Pu activity ratios confirmed that Pu contamination in the tested alpine soils originated mainly from global fallout from nuclear weapon tests conducted in the fifties and sixties. Estimation of the date of the contamination, using the 241Pu/241Am age-dating method, further confirmed this origin. However, the 241Pu/241Am dating method was limited to samples where Pu-Am fractionation was insignificant. If any, the contribution of the Chernobyl accident is negligible.

Rapid determination of plutonium isotopes in small samples using single anion exchange separation and ICP-MS/MS measurement in NH3–He mode for sediment dating

“…Since the 1940s, plutonium (Pu) isotopes have been released into the environment by a series of human nuclear activities. 239 Pu (T 1/2 = 24,100 y), 240 Pu (T 1/2 = 6561 y) and 241 Pu (T 1/2 = 14.4 y) have been not only the focus of the attention in the field of radioecology because of their high chemical toxicity and radiotoxicity [1,2], but also increasingly applied as powerful tracers for various environmental studies in recent years, such as ocean processes [3,4], lake deposition [5,6] and soil erosion [7][8][9]. More recently, plutonium isotopes were even suggested as a good primary marker for the Anthropocene by researchers [10,11].…”

Long-Term and Long-Range Migration of Radioactive Fallout in a Karst System

“…In Switzerland, some regions have been impacted by 137 Cs from Chernobyl, but no contribution of plutonium from Chernobyl has ever been determined. 238 Pu/ 239+240 Pu, 241 Am/ 239+240 Pu, and 241 Pu/ 239+240 Pu isotopic ratio in Swiss soils are respectively of 0.03, 0.39 , , and 1.5 . In addition, the Swiss population has incorporated plutonium with a 240 Pu/ 239 Pu isotopic ratio of 0.21 ± 0.06 in milk teeth and 0.18 ± 0.01 in vertebrae .…”

Characterization of 241Pu occurrence, distribution, and bioaccumulation in seabirds from northern Eurasia

“…Nuclear weapon-grade plutonium, which was another important source of this element in the environment, was characterized by a much lower 241 Pu/ 239+240 Pu activity ratio of about 0.5–4 (Irlweck and Hrnecek 1999 ; Salminen and Paatero 2009 ; Salminen-Paatero et al 2014 ). This is why the simultaneous determination of 241 Pu and the alpha emitting radioisotopes could be a useful tool for tracing plutonium sources in the environment (Corcho Alvarado et al 2011 ).…”