Spatial distribution of harmful trace elements in Chinese coals

The potential impact of harmful trace elements in coal on the ecological environment and human health is one of the hot topics in the fields of geochemistry and energy environment. Geochemical mapping plays an important role in the deep understanding of geochemical processes and their changing laws. However, previous studies have not provided the national geochemical maps of harmful trace elements in Chinese coals. In this study, the content data of 1 167 Be, 1 315 Co, 1 406 Cu, 1 191 Mo, 1 247 Th, and 1 390 Zn in Chinese coal samples are analyzed, and their average contents are measured. The supporting data are obtained from the trace elements in coal of China (TECC) database. The geochemical maps of Be, Co, Cu, Mo, Th, and Zn in Chinese coals have been published by using ArcGIS mapping. The main conclusions are as follows. The content of harmful trace elements in Chinese coals has a large span and the data distribution is positively biased, which does not conform to the normal distribution. The average content of Be, Co, Cu, Mo, Th and Zn in Chinese coals is 2.10, 5.53, 21.36, 2.19, 7.35 and 30.02 mg/kg, respectively. The spatial distribution of the content of harmful trace elements in Chinese coals is extremely uneven. The spatial distribution pattern of the content of harmful trace elements in coal is dependent on many factors, such as source-rock, hydrothermal action, water migration, etc. Among them, hydrothermal action is a typical feature of abnormal concentration of harmful trace elements in coal. This study can provide intuitive and effective references for geochemical research and environmental management of coal mines.