Bonczyk Michal, Michalik Boguslaw, Chmielewska Izabela
a Central Mining Institute , Silesian Centre for Environmental Radioactivity , Katowice , Poland.
Isotopes Environ Health Stud. 2017 Mar;53(1):104-110. doi: 10.1080/10256016.2016.1116987. Epub 2016 Feb 23.
The radioactive lead isotope Pb occurs in waste originating from metal smelting and refining industry, gas and oil extraction and sometimes from underground coal mines, which are deposited in natural environment very often. Radiation risk assessment requires accurate knowledge about the concentration of Pb in such materials. Laboratory measurements seem to be the only reliable method applicable in environmental Pb monitoring. One of the methods is gamma-ray spectrometry, which is a very fast and cost-effective method to determine Pb concentration. On the other hand, the self-attenuation of gamma ray from Pb (46.5 keV) in a sample is significant as it does not depend only on sample density but also on sample chemical composition (sample matrix). This phenomenon is responsible for the under-estimation of the Pb activity concentration level often when gamma spectrometry is applied with no regard to relevant corrections. Finally, the corresponding radiation risk can be also improperly evaluated. Sixty samples of coal mining solid tailings (sediments created from underground mining water) were analysed. Slightly modified and adapted to the existing laboratory condition, a transmission method has been applied for the accurate measurement of Pb concentration . The observed concentrations of Pb range between 42.2 ÷ 11,700 Bq·kg of dry mass. Experimentally obtained correction factors related to a sample density and elemental composition range between 1.11 and 6.97. Neglecting this factor can cause a significant error or underestimations in radiological risk assessment. The obtained results have been used for environmental radiation risk assessment performed by use of the ERICA tool assuming exposure conditions typical for the final destination of such kind of waste.
放射性铅同位素Pb存在于金属冶炼和精炼行业、天然气和石油开采产生的废物中，有时也存在于地下煤矿产生的废物中，这些废物经常被排放到自然环境中。辐射风险评估需要准确了解此类材料中Pb的浓度。实验室测量似乎是环境Pb监测中唯一适用的可靠方法。其中一种方法是伽马射线能谱法，这是一种测定Pb浓度的非常快速且经济高效的方法。另一方面，样品中来自Pb（46.5 keV）的伽马射线的自吸收很显著，因为它不仅取决于样品密度，还取决于样品的化学成分（样品基质）。当不考虑相关校正而应用伽马能谱法时，这种现象往往会导致Pb活度浓度水平被低估。最后，相应的辐射风险也可能被不当评估。对60个煤矿固体尾矿（由地下矿井水产生的沉积物）样本进行了分析。对现有实验室条件进行了轻微修改和调整后，采用了一种透射方法来准确测量Pb浓度。观测到的Pb浓度范围为42.2÷11,700 Bq·kg干质量。实验获得的与样品密度和元素组成相关的校正因子范围在1.11至6.97之间。忽略这个因素可能会在放射风险评估中导致重大误差或低估。所获得的结果已用于通过使用ERICA工具进行的环境辐射风险评估，该评估假设了此类废物最终处置地的典型暴露条件。
