Garger E K, Kashpur V, Paretzke H G, Tschiersch J
Institute of Radioecology UAAS, Kiev, Ukraine.
Radiat Environ Biophys. 1998 Feb;36(4):275-83. doi: 10.1007/s004110050082.
Size distribution measurements of particulate radionuclides were performed at two sites in the Chernobyl 30-km exclusion zone using several cascade impactors. The results obtained in the period September 1986 till June 1993 were discussed with regard to the general assumption of a log-normal activity size distribution in inhalation dose assessment. At Zapolie (a site 14 km from the Chernobyl reactor) a bimodal distribution was observed in 91% of all measured distributions. In most cases the medians were about 4 microns and in the range 20-30 microns. According to soil granulometric data this finding was explained by superimposing two processes: local resuspension and advective transport of radioactive aerosol from highly contaminated territories. The mean air concentration showed an increasing proportion of inhalable particles over the years since the accident. In 1993 the inhalable fraction was about 48% of the total concentration. At Pripyat, a site situated within a highly contaminated area, unimodal types of size distributions were predominant with the median diameters in the range 5-10 microns for 137Cs. For the three nuclides 137Cs, 144Ce and 106Ru, very similar types of distribution were observed. Apparently, the radioactive aerosol was of fuel origin. During a forest fire at a distance of 17 km, the majority of the radioactivity was associated with submicrometer particles with median diameters in the range 0.28-0.50 micron.
利用多个级联撞击器，在切尔诺贝利30公里禁区内的两个地点对颗粒放射性核素进行了尺寸分布测量。针对吸入剂量评估中对数正态活度尺寸分布的一般假设，讨论了1986年9月至1993年6月期间获得的结果。在扎波列（距离切尔诺贝利反应堆14公里的一个地点），在所有测量分布中有91%观察到双峰分布。在大多数情况下，中位数约为4微米，范围在20 - 30微米。根据土壤粒度数据，这一发现可通过叠加两个过程来解释：局部再悬浮和来自高污染地区的放射性气溶胶的平流输送。自事故发生以来，多年来平均空气浓度显示可吸入颗粒的比例在增加。1993年，可吸入部分约占总浓度的48%。在普里皮亚季，一个位于高污染区域内的地点，单峰尺寸分布类型占主导，137Cs的中位直径在5 - 10微米范围内。对于137Cs、144Ce和106Ru这三种核素，观察到非常相似的分布类型。显然，放射性气溶胶来自燃料。在距离17公里处发生森林火灾期间，大部分放射性与中位直径在0.28 - 0.50微米范围内的亚微米颗粒有关。
