Heavy metals pollution and edible analysis of fish in the sub-alpine Dajiuhu Peatland, central China

【Objective】The Dajiuhu subalpine peatland in central China acts as a crucial sink for heavy metals through cold-condensation and immobilization. This study conducted an integrated multi-media assessment (topsoil, atmospheric deposition, pond sediments, and fish) to quantify contamination, infer sources, and evaluate food-safety risks. 【Results】Topsoil concentrations followed the order: Zn > Cr > Pb > Ni > Cu > As > Cd > Hg, with Zn, Cd, Pb, and Ni exceeding Hubei background values. Moss analysis confirmed significant atmosphere-driven inputs for Cd and Zn. Risk indices (Igeo and RI) indicated generally low-to-moderate contamination in topsoil, whereas pond sediments exhibited Cd-dominated high ecological risk. Multivariate statistics (PCC/PCA) resolved three primary sources: diffuse combustion/open-burning (As–Pb–Cr), construction-related activities (Cd–Cu), and a mixed dust/agricultural/traffic influence (Zn). In fish, essential metals (Zn, Cu) were higher than non-essential metals; Hg showed the highest BCF, whereas As was the most frequent metal exceeding guideline values in muscle, though PTWI-based intake risks remained low. Overall, Cd should be prioritized for sediment ecological risk management, while Hg and As warrant continued biomonitoring and speciation-focused risk evaluation to safeguard this protected wetland.