PLUTONIUM DISTRIBUTION IN ROCKY FLATS SOIL

Plutonium concentrations in Rocky Flats soil were inversely proportional to distance from the plutonium source, to depth of the sample, and to particle size of sieved soil samples. Coefficients of variation ranged to more than 300%, and frequency distributions of plutonium concentrations in samples were highly skewed. The plutonium distribution patterns and known characteristics of the plutonium source indicated that the mechanisms of environmental dispersion may have involved the attachment of plutonium oxide to soil particles; primary dissemination of contaminant from the source by wind; and weathering, microdispersal, and penetration into soil of deposited particles. The high degree of spatial variability, in particular, suggested that the most common functional form of the contaminated soil during dissemination was probably an agglomerated particle containing many plutonium oxide and soil particles bound together. © 1978 Health Physics Society.