Spitz H B, Rajaretnam G
National Institute for Occupational Safety and Health, Robert A. Taft Laboratories, Cincinnati, OH 45226-1998, USA.
Am Ind Hyg Assoc J. 1998 Jul;59(7):471-7. doi: 10.1080/15428119891010226.
Samples of aerosolized coal slag were collected during an abrasive blasting operation to determine the concentration of naturally occurring radioactive materials (NORM) in the respirable and nonrespirable fractions. Each slag fraction was analyzed using alpha and gamma spectrometry. Since the slag is insoluble, it was necessary to dissolve samples completely by fusion with potassium fluoride and, after additional transposing and separation, mount the precipitate containing radium (Ra), the main radioactive component in NORM, on a membrane filter for alpha counting. The concentration of 226Ra in coal slag was independent of the particle size fraction and equal to 2.28 picocuries/gram (pCi/g) +/- 0.43 pCi/g, which is approximately twice the typical concentration of NORM in uncontaminated soil. Analysis of NORM by gamma spectrometry identified low concentrations of uranium, thorium, and potassium, all primordial radioactive materials that are commonly encountered in normal background soil. Integral exposure to workers from inhalation of NORM during abrasive blasting with coal slag is extremely low and could be essentially eliminated by use of appropriate respiratory protection. External radiation exposure to workers handling large quantities of NORM-contaminated coal slag during shipping or storage is also low, but would vary depending on the concentration of NORM in the slag.
在喷砂作业期间收集了雾化煤渣样本，以确定可吸入部分和不可吸入部分中天然存在的放射性物质（NORM）的浓度。使用α和γ能谱分析法对每个煤渣部分进行了分析。由于煤渣不溶，有必要通过与氟化钾熔融将样本完全溶解，经过进一步转移和分离后，将含有镭（Ra）（NORM中的主要放射性成分）的沉淀物置于膜滤器上进行α计数。煤渣中226Ra的浓度与颗粒大小部分无关，等于2.28皮居里/克（pCi/g）±0.43 pCi/g，这大约是未受污染土壤中NORM典型浓度的两倍。通过γ能谱分析法对NORM进行分析，确定了低浓度的铀、钍和钾，这些都是在正常背景土壤中常见的所有原生放射性物质。在使用煤渣进行喷砂作业期间，工人因吸入NORM而产生的累积暴露极低，通过使用适当的呼吸防护基本上可以消除。在运输或储存期间处理大量受NORM污染的煤渣的工人所受到的外部辐射暴露也很低，但会因煤渣中NORM的浓度而异。
