the soil results in a very markedly increased adsorption of strontium throughout the range of acidity or alkalinity studied. make plant uptake of strontium much less likely. The effect is to This phenomenon will be discussed more fully in a subsequent section on hazard evaluation. Movement of radioactive particles by wind erosion has been studied by the Hanford Group. This study was designed to investigate particle pickup as well as the relative efficiencies of various surfaces for re-~ taining small particles. Using a 20 foot circular sand plot as the contaminated study area, “it was found that the source was seriously de- pleted following two days of fresh surface winds of 15 to 25 mph, indicating that the natural surface of this particular type of soil is highly erodible and that particles deposited on such a surface are susceptible to subsequent translocation in windy weather. A second experiment was a study of the relative retentive efficiency of grasscovered, rock-covered, furrowed and fence-protected surfaces. Prelin- analysis of the data indicated that rock-covered and grass-covered surfaces retain particles equally well. The furrowed surface retained particles poorly when compared to the grass or rock-covered surfaces. The highest particle retention was observed in the immediate lee of the fence, but this result is somewhat open to question because these areas were shaded from the sun and were noticeably wetter than the other areas. Both strontium-89 and strontium-90 are examples of radioisotopes having gaseous precursors and are thus subject to a high degree of fractionation. To illustrate the decay chain, the following equations are shown: Krypton-89 sport Rubidium-89 min +--+ is eo Strontium-89 age ane aareete Krypton-90 sae 35 Rubidium-90 eo Strontium-90 sat Yttrium-90 14-4 ont Zirconiwi-90 (stable) Thus, the duration of the ‘fireball, at which time radioactive particles are being formed, will have a marked effect upon the availability of dL