Size fractionation methods: measuring plutonium in respirable dust.

Methods used to evaluate the inhalation hazard of soil contaminated with plutonium were investigated. Four soil fractionation procedures were used to separate three size fractions of soil particles taken from two locations at the Department of Energy's Rocky Flats facility. The results show that increasing amounts of soil mass and plutonium activity (0.5 to 38 percent and 7 to 84 percent, respectively) remain in the fraction of soil smaller than 10 micrometers as the in situ particle associations are increasingly disrupted by physical and chemical forces. The introduction of forces of dispersion unrelated to ambient conditions yields results that are unrelated to the original particle associations.