Soil organic matter and migration properties of ^239,240Pu and ²⁴¹Am

Belarusian State University, Radiochemistry Laboratory, F. Skariny Ave. 4, 220050 Minsk, Belarus

Abstract

Humus influence on mobility of plutonium and americium in soil has been investigated. To do this the entrance of radionuclides into soil water solutions with different organic matter concentration and the distribution of ^239,240Pu and ²⁴¹Am between humus fractions of soil has been analyzed. The mineral and organic soils with distinct quantitative and qualitative composition of humus, contaminated by radionuclides of Chernobyl origin have been studied. The groups of fulvic (FA) and humic acids (HA) which differ in their composition and solubility in water were extracted from soils and the content of ^239,240Pu and ²⁴¹Am in these organic fractions was detected. It was established that humus substances (HS) mainly promote the fixation of ^239,240Pu and ²⁴¹Am in solid phase of soil. The humus of organic soils promotes the fixation of plutonium and americium to a greater extent than HS of mineral soils. That is one of the reasons of lower mobility of ^239,240Pu and ²⁴¹Am in organic soils. A higher ability of plutonium to form the difficultly soluble complexes with HS compare to americium may be a factor of higher mobility of americium in soil.