Lead accumulation in wild mushrooms from Leicestershire, UK: species differences and implications for environmental monitoring

Lead (Pb) is a persistent neurotoxic metal(loid) with widespread occurrence in urban environments. This study evaluated Pb concentrations in wild mushrooms collected from 22 sites across Leicestershire, UK, with a focus on species-specific accumulation and intra-species tissue partitioning. A total of 106 mushrooms, representing 14 species, were analysed using ICP-MS following acid digestion. Species identification was confirmed through DNA barcoding. Pb was detected in 91% of the samples, with concentrations ranging from 0.30 to 10.57 mg/kg dry weight. The highest levels were observed in Coprinus atramentarius (mean: 6.64 mg/kg), followed by Mycena citrinomarginata (4.64), Panaeolus foenisecii (3.94), Agaricus bitorquis (2.37), and Marasmius oreades (1.32) (p < 0.05). Compared to earlier single-species studies focusing on A. bitorquis, this work provides a broader comparative analysis across multiple taxa. In M. citrinomarginata, Pb was significantly more concentrated in caps than stipes (4.23 vs. 2.51 mg/kg; p < 0.01), supporting known patterns of apical bioaccumulation. Pb concentrations exceeded the EU Maximum Allowable Concentration for cultivated mushrooms (0.3 mg/kg) in 38.5% of the dataset. Geospatial analysis identified elevated Pb levels in samples from the North-West and North-East quadrants of Leicester, consistent with legacy land-use patterns, although differences were not statistically significant. Updated health risk assessments confirmed no significant non-carcinogenic or carcinogenic risk for adults or children from occasional consumption. This study expands previous Pb biomonitoring in mushrooms by identifying additional high-accumulating species and reinforces the value of fungal biomonitors in environmental surveillance. These findings support the integration of wild mushroom data with soil and atmospheric Pb mapping in urban health policy and land management.