Johnson C J, Tidball R R, Severson R C
Science. 1976 Aug 6;193(4252):488-90. doi: 10.1126/science.941018.
Plutonium-239 in the fine particulate soil fraction of surface dust is subject to suspension by air currents and is a potential health hazard to humans who may inhale it. This respirable particulate fraction is defined as particles less than or equal to 5 micrometers. The respirable fraction of surface dust was separated by ultrasonic dispersion and a standard water-sedimentation procedure. Plutonium concentration in this fraction of off-site soils located downwind from the Rocky Flats Nuclear Weapons Plant (Jefferson County, Colorado) were as much as 380 times the background concentration. It is prposed that this method of evaluation defines more precisely the potential health hazard from the respirable fraction of plutonium-contaminated soils.
地表灰尘细颗粒土壤部分中的钚-239易被气流悬浮，对可能吸入它的人类存在潜在健康危害。这种可吸入颗粒物部分被定义为直径小于或等于5微米的颗粒。通过超声分散和标准水沉降程序分离地表灰尘的可吸入部分。落基弗拉特核武器工厂（科罗拉多州杰斐逊县）下风处场外土壤的这一部分中的钚浓度比背景浓度高多达380倍。有人提出，这种评估方法能更精确地界定受钚污染土壤可吸入部分带来的潜在健康危害。
