Oxford Resilient Buildings and Landscapes Laboratory (OxRBL), School of Geography and the Environment, University of Oxford, South Parks Road, Oxford, OX1 3QY, U.K.
Marine Isotope Geochemistry, Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany.
Environ Sci Technol. 2023 Aug 22;57(33):12362-12375. doi: 10.1021/acs.est.3c00153. Epub 2023 Jul 12.
This study introduces a novel methodology for utilizing historic built environments as reliable long-term geochemical archives, addressing a gap in the reconstruction of past anthropogenic pollution levels in urban settings. For the first time, we employ high-resolution laser ablation mass spectrometry for lead isotope (Pb/Pb and Pb/Pb) analysis on 350-year-old black crust stratigraphies found on historic built structures, providing insights into past air pollution signatures. Our findings reveal a gradual shift in the crust stratigraphy toward lower Pb/Pb and higher Pb/Pb isotope ratios from the older to the younger layers, indicating changes in lead sources over time. Mass balance analysis of the isotope data shows black crust layers formed since 1669 primarily contain over 90% Pb from coal burning, while other lead sources from a set of modern pollution including but not limited to leaded gasoline (introduced after 1920) become dominant (up to 60%) from 1875 onward. In contrast to global archives such as ice cores that provide integrated signals of long-distance pollution, our study contributes to a deeper understanding of localized pollution levels, specifically in urban settings. Our approach complements multiple sources of evidence, enhancing our understanding of air pollution dynamics and trends, and the impact of human activities on urban environments.
本研究提出了一种利用历史建筑环境作为可靠的长期地球化学档案的新方法，解决了在城市环境中重建过去人为污染水平的空白。我们首次在 350 年历史的建筑结构上发现的黑色积层中使用高分辨率激光烧蚀质谱法对铅同位素（Pb/Pb 和 Pb/Pb）进行分析，深入了解过去的空气污染特征。我们的研究结果表明，随着时间的推移，铅源发生了变化，在从旧层到新层的过程中，壳层的 Pb/Pb 和 Pb/Pb 同位素比值逐渐降低。对同位素数据的质量平衡分析表明，自 1669 年以来形成的黑色积层主要含有 90%以上来自燃煤的 Pb，而其他一系列现代污染源（包括但不限于 1920 年后引入的含铅汽油）的 Pb 源则从 1875 年开始变得占主导地位（高达 60%）。与提供长距离污染综合信号的全球档案（如冰芯）不同，本研究有助于更深入地了解局部污染水平，特别是在城市环境中。我们的方法补充了多种证据来源，增进了我们对空气污染动态和趋势以及人类活动对城市环境影响的理解。
