Accumulation, transport and potential sources of chemical elements in the soil-mushroom systems in a temperate forest

Mushrooms, as key components of forest ecosystems, have the ability to accumulate chemical elements (CMs) but their biogeochemical processes and element sources remain poorly understood. This study investigated the contents and sources of K, Ca, Na, Mg, Fe, Cu, Zn, Mn, Ni, Pb, Cd, As, Al, Co, and Ba in 34 mushroom species and their rhizosphere soils (RS) from the central Qilian Mountains, and the associated health and ecological risks. The results revealed that Al, Fe, and Zn exhibited the highest contents among the studied tissues, including the pileus, stipe, and whole mushrooms, ranging from 53.0 to 794, 27.7-1.19 × 10³, and 74.0-2.85 × 10³ mg kg^-1, 65.3-851, 34.1-950, and 122-720 mg kg^-1; and 20.2-233, 25.6-444, and 80.1-245 mg kg^-1. K, Zn, and Cd exhibited high accumulation abilities in most species, but there are obvious differences in the accumulation ability in the pileus and stipes. Health Risk model showed that children consuming these mushrooms had greater potential health risks than adults. Results further demonstrated that the soil pollution was generally slight, and Pb and Cd as the primary contributors. Principal Component Analysis (PCA), Positive Matrix Factorization (PMF), and correlation analysis identified five major sources of soil CMs: natural geological processes, soil dust, traffic emissions, industrial and agricultural activities. This study shows that Na, Cu, and As in mushrooms may mainly originate from atmospheric deposition, and soil pH, organic carbon (SOC), and carbonate (CaCO₃) were also found to be important factors influencing the accumulation of elements in mushrooms.