Wehner A P, Wilerson C L, Stevens D L
Environ Res. 1984 Oct;35(1):211-7. doi: 10.1016/0013-9351(84)90129-4.
To determine pulmonary deposition and clearance of inhaled volcanic ash, rats received a single 60-min, nose-only exposure to neutron-activated ash. Over a period of 128 days after exposure, the rats were sacrificed in groups of five animals. Lungs were analyzed for the radionuclide tracers 46Sc, 59Fe, and 60Co by gamma-ray spectrometry. The alveolar ash burdens, determined by the radionuclides 46Sc and 59Fe, are in good agreement for the majority of samples analyzed, indicating ash particulate levels in the lungs, rather than leached radionuclides. The ash deposition estimates based on 60Co were appreciably lower for the lungs, indicating that 60Co leached from the ash. Approximately 110 micrograms ash, or 6% of the inhaled ash, was initially retained in the deep lung. The biological half-time of the alveolar ash burden was 39 days. After 90 days, the mean lung burden had decreased to about 20% of its initial value; 128 days after exposure, about 10% remained.
为了确定吸入火山灰在肺部的沉积和清除情况，大鼠接受了单次60分钟的仅经鼻暴露于中子活化灰的实验。在暴露后的128天内，将大鼠按每组5只动物进行处死。通过γ射线能谱法分析肺组织中的放射性核素示踪剂46Sc、59Fe和60Co。由放射性核素46Sc和59Fe测定的肺泡灰负荷，在大多数分析样本中结果吻合良好，表明肺部的灰颗粒水平，而非浸出的放射性核素。基于60Co的灰沉积估计值在肺部明显较低，表明60Co从灰中浸出。最初约110微克的灰，即吸入灰的6%，保留在深部肺组织中。肺泡灰负荷的生物学半衰期为39天。90天后，平均肺负荷降至其初始值的约20%；暴露128天后，约10%的灰负荷仍留存。
