铅同位素比值法对污染同源性的研究

Determination of lead isotope ratios in soil by inductively coupled plasma mass spectrometry and source identification

目的采用电感耦合等离子体质谱法(ICP-MS)建立元素同位素比值测定方法,对不同污染水平土壤中总铅和铅的同位素研究,了解相应的铅污染情况,并开展可能污染源的追溯。方法土壤样品经微波消解、电感耦合等离子体发射质谱法测定铅总含量和铅的同位素比值。结果采用选择脉冲检测模式,当铅同位素浓度在20μg/L^50μg/L范围内所测得的同位素比值几乎恒定不变,RSD 0.10%(n=6)。铅同位素比值的短期稳定性206Pb/207Pb,206Pb/208Pb的RSD分别为0.15%、0.16%,长期稳定性分别为0.18%、0.13%。结论利用此方法可以对环境土壤样品中总铅及铅的同位素分析,并结合相关的现场调查,为污染源的判断提供科学依据。

Objective To establish the isotope ratio determination method and monitor the lead isotope in soil with inductively coupled plasma mass spectrometry （ICP -MS） to have a full understanding and trace the lead contamination. Methods The ratio of total lead content to lead isotope in soil is measured by ICP - MS after microwave digestion. Results Pulse detection mode was applied for sample determination. The concentration of lead isotopes ranged from 20 μg/L - 50 μg/L, and the ratio of lead isotope detected within this range was stable, the relative standard deviation was 0.10% （n = 6）, and the RSD of 206Pb/ 207 Pb and 206Pb/2os Pb with short - time stability were 0. 15% and 0.16% respectively, while the RSD of 206pb/207 Pb and 206Pb/2os Pb with long - time stability were 0, 18% and 0.13% respectively. Conclusion This method can be applied to ana- lyze the total lead content and lead isotopes in soil and trace the contamination source with the help of epidemiological investiga- tion.