Effect of coal mining activities on the environment of Tetraena mongolica in Wuhai, Inner Mongolia, China—A geochemical perspective

• We study soil geochemistry in Wuhai over time, with depth and horizontal distance.
• The range of leaching contamination of gob piles is 10 m with maximum impact at 2 m.
• The range of volatilization contamination is about 3–5 km.
• The inhabited area of Tetraena mongolica has a high Mo concentration.
• The distribution of Tetraena mongolica may be related to coal resources.

The main objective of this study is to investigate the geochemical impact of gob piles on the environment of Tetraena mongolica, a Chinese nationally protected plant. Twenty-five major and trace elements in samples of soil, gangue, roof and floor of coal seams collected from Wuhai, Inner Mongolia, China, were analyzed by atomic fluorescence spectrometry (AFS), X-ray fluorescence (XRF) and inductively coupled plasma mass spectrometry (ICP-MS). The results show that the elements, such as Cu, Pb, Mo, and As, were highly enriched in soil, coal and coal gangue. Between 2003 and 2012, heavy metal concentrations had increased in soil due to mining activities. Leaching and volatilization are the two main pathways that gob piles affect the environment, with the leaching range of the gob piles extending about 0–10 m while the range for volatilization is 3–5 km. The concentration of Cu, Pb, Mo, and As in T. mongolica also shows a positive correlation with the elemental compositions of the roof and floor of the coal seam, and adult individuals have a higher correlation than juveniles. Therefore, the distribution of coal resources and the local geology contribute to the restricted range of T. mongolica in Wuhai.