Strong association of fallout plutonium with humic and fulvic acid as compared to uranium and137Cs in Nishiyama soils from Nagasaki, Japan

Abstract

To investigate the formation of mobile organic plutonium, we analyzed the plutonium contents of the fulvic (FA) and humic (HA) acids from the soil samples obtained at Nishiyama, Nagasaki, Japan. The percentages of the plutonium bound strongly to HA and to FA vs. the total plutonium in the soil were 5-10% and 1%, respectively, at the depth of 0-0.1 m, much higher values than those of 137Cs and uranium. After being weathered for 51 years under a temperate climate, the initial highfired oxides of fallout plutonium have become as chemically reactive plutonium from nuclear fuel reprocessing plants.

Radionuclides from Chernobyl hot particles in the environment of North-Eastern Poland - A leaching experiment

“…It rather suggests complexing by humic acid as the only reason of plutonium presence. This results strongly supports some earlier results by other authors [8][9][10][11] on the possibility of a humic acid complexation of plutonium, (but not the fulvic acid complexation) which then might be sometimes (in basic conditions) far more mobile in the environment then it was classically assumed. In Fig.…”

“…Then, after many years of a decomposition (corrosion) in environmental conditions radionuclides from HPs might be leached out and might go to different chemical forms. Pu, Am or Cm could be bio-available or more general speaking leachable mostly if they are complexed by humic or fulvic acids [8][9][10][11]. To prove this feature present experiment was performed.…”

On the study of Th(IV)-humic acid interactions by competition sorption studies with silica and determination of global interaction constants

“…The importance of colloidal matter on the facilitated transport of heavy metals in natural systems is now well accepted [1][2][3][4]. It is of particular importance to determine the influence of humic substances (HS, humic and fulvic acids, HA/FA), constituting nearly half of the dissolved organic matter present in groundwater [5][6][7], on the migration of radionuclides, particularly the actinide elements.…”

A study of the bioavailability of90Sr,137Cs, and239+240Pu in soils at two locations of Spain affected by different radionuclide contamination events

“…For 239+240 Pu, the exchangeable fraction was the least important in both soils. Whereas in Bazagona these isotopes were mainly bound to organic matter, as found by other authors [12,13,14], in Palomares they were mainly detected in the residual fraction. This different association is probably due to the chemical form of plutonium incorporated to each soil.…”

“…Given the associated uncertainty, this ratio is coherent with the value of 1.66 for global fallout at the latitude of Spain [9,11]. 137 Cs bound to the organic matter fraction is coherent with the low percentage of radiocaesium that binds to humic and fulvic acids, which are a significant component of the organic matter of soil [12,13]. For 239+240 Pu, the exchangeable fraction was the least important in both soils.…”