Spatial Distribution and Soil-to-Fungus Transfer of Cadmium, Copper, and Zinc in Urban and Rural Green Spaces of Leicestershire, UK

Urban and rural green spaces can accumulate potentially toxic elements in topsoil and support wild mushrooms that concentrate metals. This study quantified Cd, Cu, and Zn in topsoil and naturally growing wild mushrooms from Leicestershire, UK, and evaluated spatial patterns, species- and tissue-specific accumulation, apparent soil-to-fungus transfer, and a screening dietary exposure scenario. Samples were acid-digested and analysed by ICP-MS; left-censored data were treated using R/NADA, and apparent bioconcentration factors (BCFs) were calculated from matched quadrant-level medians. Urban topsoils showed higher median Cu and Zn than rural topsoils, whereas Cd medians were similar; the SW quadrant had the highest topsoil medians for all three metals. Mushroom patterns were more heterogeneous: SW had the highest median Cd (3.15 mg kg−1 dw), while NW had the highest median Cu and Zn, particularly Zn (301.29 mg kg−1 dw). Agaricus bitorquis caps showed the highest median Cd and Cu among retained taxa, whereas Mycena citrinomarginata showed the highest median Zn. Cd showed the strongest apparent transfer, with a pooled urban BCF of 4.66. Median Cd concentrations were below the approximate dry-weight equivalent of the European maximum level for wild fungi, although some A. bitorquis caps exceeded it. Occasional adult-consumption estimates remained below selected health-based guidance values. Wild mushrooms provide useful complementary biomonitors of biologically expressed metal availability in public green spaces.