The long-distance transport of toxic elements is a crucial external source of metals accumulated in remote forest ecosystems. Due to the harsh environmental conditions and the complexity and diversity of influencing factors in remote alpine ecosystems, research on toxic elements is very limited, especially in the dry zone. In this regard, mercury (Hg) and arsenic (As) in soil and plant samples were investigated in a Qinghai spruce forest ecosystem at Sidalong Forest Farm (SDL), in the Qilian Mountains, northwest China. The results of the study showed a significant variation in the spatial distribution of Hg and As in soils, but a highly similar spatial distribution trend was found in mosses. High Hg and As concentrations in plants were found in moss, bark, and litterfall; the concentration of Hg was particularly high (BCF > 1). The Qilian Mountain spruce forest ecosystem was contaminated with exogenous Hg and As, with Hg, in particular, being the most serious form of contamination. The study results can provide baseline data for future forest management and research in the spruce forest ecosystem in Qinghai, northwest China. © 2022 by the authors.
