Atomic Weapons Establishment, Aldermaston, Reading, Berkshire RG7 4PR, UK.
J Environ Radioact. 2011 Apr;102(4):326-30. doi: 10.1016/j.jenvrad.2011.01.001.
A novel technique has been developed for determining the (212)Pb activity of fresh waters. This is of interest to environmental monitoring programmes that utilise gross α-activity methods to screen for anthropogenic radionuclides. The contribution from (212)Pb varies, and is difficult to experimentally measure due to its relatively short half-life (t(½) = 10.6 h) and low environmental activity (<0.1 Bq l(-1)). The use of a three-stage technique that encompasses a unique form of pre-concentration, separation and analysis by liquid scintillation counting allows a lower detection limit of 0.006 Bq l(-1) with a chemical yield of 92.5 ± 5.6%. The measurement can be obtained within 7 h of sample collection, and is calculated using the radioactive decay of (212)Bi. Other naturally occurring radionuclides may also be extracted using the pre-concentration stage of the technique, with efficiencies above 90% at a range of pH values.
一种新的技术已经被开发出来，用于测定新鲜水中的（212）Pb 活度。这对于利用总α-活度方法筛选人为放射性核素的环境监测计划具有重要意义。由于（212）Pb 的半衰期相对较短（t(½) = 10.6 h）且环境活度较低（<0.1 Bq l(-1))，其贡献难以通过实验测量。使用一种包含独特的预浓缩、分离和液体闪烁计数分析的三阶段技术，可以以 0.006 Bq l(-1)的更低检测限和 92.5 ± 5.6%的化学收率进行测量。该测量可以在样品采集后的 7 小时内获得，并使用（212）Bi 的放射性衰变进行计算。该技术的预浓缩阶段还可以提取其他天然放射性核素，在一系列 pH 值下效率超过 90%。
