Species- and Tissue-Specific Accumulation of Cd, Cu and Zn in Wild Mushrooms from Leicestershire, UK

Introduction: Metal accumulation in wild mushroom fruiting bodies is influenced by fungal taxonomy, fruiting-body structure and the environmental metal burden of the habitats where they develop. This study assessed species- and tissue-specific patterns of cadmium (Cd), copper (Cu) and zinc (Zn) accumulation in wild mushrooms from urban and rural green spaces in Leicestershire, UK, and interpreted them in relation to local topsoil metal concentrations.

Methods: Wild mushroom fruiting bodies were collected from public green spaces in Leicester and Bradgate Park. Species identity was confirmed by macroscopic assessment and DNA barcoding. The retained dataset included Agaricus bitorquis, Panaeolus foenisecii, Marasmius oreades, Coprinopsis atramentaria and Mycena citrinomarginata. Samples were cleaned, dried, homogenised, digested and analysed for Cd, Cu and Zn by ICP–MS. Where sufficient biomass was available, caps and stipes were analysed separately.

Results and Discussion: Urban topsoils showed higher median Cu and Zn concentrations than rural topsoils, whereas Cd medians were similar. The SW sector showed the highest topsoil medians for all three metals, indicating spatial heterogeneity in environmental metal burden. Mushroom accumulation differed markedly between taxa and did not simply mirror topsoil concentrations. A. bitorquis showed the highest median Cd concentration (3.878 mg kg⁻¹ dry weight) and Cu concentration (114.908 mg kg⁻¹ dry weight), whereas C. atramentaria and M. oreades showed the lowest Cd medians. Median Zn was highest in M. citrinomarginata (111.359 mg kg⁻¹ dry weight), followed by C. atramentaria (104.036 mg kg⁻¹ dry weight). In A. bitorquis from St Augustine Road, caps showed higher median concentrations than stipes for Cd, Cu and Zn.

Conclusions: Cd, Cu and Zn accumulation in wild mushrooms from Leicestershire was species- and tissue-dependent and occurred against a spatially heterogeneous topsoil metal background. These findings support considering fungal identity, fruiting-body tissue and local environmental metal concentrations when interpreting wild mushrooms as food-safety matrices or environmental biomonitors.