Assessment of edible mushroom bioaccumulation via portable XRF and micro-XRF: implications for environmental impact assessment, food quality evaluation and mineral resource prospecting

This case study employed portable X-ray fluorescence (pXRF) spectrometry to evaluate elemental concentrations in edible mushrooms from the Bailing Cu–Zn mining area, China, and micro-X-ray fluorescence (micro-XRF) imaging to document elemental spatial extent in mushroom samples. pXRF-determined concentrations were calibrated, and the mean relative errors (MREs) after calibration were <14% for all elements (S, K, Ca, Cu, Zn, As and Rb) except for Fe (MRE = 20%). Arsenic concentrations in Lepista nuda (wood blewit) from mining areas reached 42 mg kg⁻¹, significantly higher than nearby non-mining areas (2–5 mg kg⁻¹) and far exceeding the Chinese food safety limit of 0.5 mg kg⁻¹. Arsenic concentrations in wood blewits were positively correlated with soil As levels (coefficient of determination (R²) = 0.434, P < 0.01), highlighting their potential as bioindicators for mineral exploration. Copper concentrations in Lepista nuda were also high, with some reaching up to 548 mg kg⁻¹. Micro-XRF imaging reveal that Cu is primarily concentrated on the margin (edge) of the cap of wood blewits. Mining activities in the research area caused elevated As and Cu concentrations in wild edible mushrooms (Lepista nuda and Armillaria gallica), posing a significant health risk to local residents through mushroom consumption as a pathway for toxic exposure.