Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Environ Pollut. 2022 Feb 15;295:118605. doi: 10.1016/j.envpol.2021.118605. Epub 2021 Dec 8.
The lack of emission data of major Cd-emitting enterprises has long limited the source apportionment of soil cadmium (Cd). Non-ferrous metal enterprises (NMEs) contribute the most Cd emissions in China in recent years. We estimated the cumulative Cd emission of 8750 NMEs across China through public data collection and material balance methods for the first time. The results showed that the total Cd emissions were estimated at 133,177 tons, of which 78.68% contributed by zinc primary smelting and mining. The emission hotspots are mainly concentrated in the south of the Yangtze River, such as Nanling Mountain areas, Nanpan River Basin, and Jincheng River Basin, as well as a few parts of the North and Northwest China. Then a significant positive spatial correlation was furtherly detected between NMEs and soil Cd, except for secondary smelting enterprises. Moreover, the hotspots of soil Cd pollution caused by NMEs were identified across China. By promoting the accounting calibrator from annual emission intensity of regional (mainly provincial) scale to the cumulative emission of site-specific enterprise in its entire life cycle, this study realized the finer description of the spatial heterogeneity of Cd emission from non-ferrous industry on a large scale and make it possible to refine the reliability of follow-up site-specific source apportionment, by introducing the emission intensity instead of the enterprise sites density. Finally, a modified approach for the regional source apportionment of soil pollution was proposed to obtain a more realistic and precise drawing. The results pointed out key NMEs subcategories and the affected hotspots which require continuous strengthening of Cd-related rectification. This methodological framework is expected to contribute to the precise management and differential sources control of Cd pollution and can be further extended to other pollutants for the precise targeting of key industries and hotspots during source pollution control in the future.
主要镉排放企业排放数据的缺乏长期以来限制了土壤镉（Cd）的来源解析。近年来，有色金属企业（NMEs）在中国的镉排放量最大。我们首次通过公开数据收集和物料平衡方法估算了中国 8750 家 NMEs 的累积 Cd 排放量。结果表明，总 Cd 排放量估计为 133177 吨，其中锌初级冶炼和采矿贡献了 78.68%。排放热点主要集中在长江以南，如南岭地区、南盘江流域和金成河流域，以及中国北方和西北部的一些地区。然后，进一步检测到 NMEs 与土壤 Cd 之间存在显著的正空间相关性，除了二次冶炼企业。此外，还在中国各地确定了由 NMEs 引起的土壤 Cd 污染热点。通过将区域（主要是省级）尺度的年度排放强度核算校准器推广到整个生命周期中特定企业的累积排放量，可以实现对大规模有色金属行业 Cd 排放空间异质性的更精细描述，并通过引入排放强度而不是企业地点密度来提高后续特定地点源分配的可靠性。最后，提出了一种改进的区域土壤污染源分配方法，以获得更真实和精确的结果。研究结果指出了需要持续加强 Cd 相关整改的关键 NMEs 亚类和受影响的热点。该方法框架有望为 Cd 污染的精确管理和差异源控制做出贡献，并可进一步扩展到其他污染物，以便在未来的污染源控制中针对关键行业和热点进行精确瞄准。
