Nicholas School of the Environment, Duke University, Durham, North Carolina 27708, United States.
College of Geoscience and Survey Engineering, China University of Mining and Technology, Beijing 100083, China.
Environ Sci Technol. 2023 Aug 22;57(33):12259-12269. doi: 10.1021/acs.est.3c03456. Epub 2023 Aug 9.
Despite extensive research and technology to reduce the atmospheric emission of Pb from burning coal for power generation, minimal attention has been paid to Pb associated with coal ash disposal in the environment. This study investigates the isotopic signatures and output rates of Pb in fly ash disposal in China, India, and the United States. Pairwise comparison between feed coal and fly ash samples collected from coal-fired power plants from each country shows that the Pb isotope composition of fly ash largely resembles that of feed coal, and its isotopic distinction allows for tracing the release of Pb from coal fly ash into the environment. Between 2000 and 2020, approx. 236, 56, and 46 Gg Pb from fly ash have been disposed in China, India, and the U.S., respectively, posing a significant environmental burden. A Bayesian Pb isotope mixing model shows that during the past 40 to 70 years, coal fly ash has contributed significantly higher Pb (∼26%) than leaded gasoline (∼7%) to Pb accumulation in the sediments of five freshwater lakes in North Carolina, U.S.A. This implies that the release of disposed coal fly ash Pb at local and regional scales can outweigh that of other anthropogenic Pb sources.
尽管有大量的研究和技术致力于减少发电用煤燃烧过程中的大气铅排放，但对于与煤灰处置相关的铅问题，人们关注甚少。本研究调查了中国、印度和美国的粉煤灰处置中铅的同位素特征和排放量。对来自每个国家的燃煤电厂的入炉煤和粉煤灰样品进行的两两比较表明，粉煤灰的铅同位素组成在很大程度上与入炉煤相似，其同位素差异可用于追踪从煤飞灰中释放到环境中的铅。在 2000 年至 2020 年期间，中国、印度和美国分别处理了约 236、56 和 46 吉克铅的粉煤灰，这对环境造成了重大负担。贝叶斯铅同位素混合模型表明，在过去的 40 到 70 年中，煤灰对美国北卡罗来纳州五个淡水湖沉积物中铅积累的贡献显著高于含铅汽油（约 26%比约 7%）。这意味着在当地和区域范围内，处置煤灰中的铅释放量可能超过其他人为铅源的释放量。
