Orywal et al. 2021 — Heavy metals in dried wild-grown mushrooms, Poland
This study measured mercury (Hg), lead (Pb), cadmium (Cd), and arsenic (As) in 80 samples of dried wild-grown mushrooms (Boletus edulis and Xerocomus badius) purchased at retail in Poland, and assessed the consumer health risk associated with standard portion consumption. Boletus edulis showed markedly higher Hg and Cd concentrations than Xerocomus badius. Consumption of a standard dried portion of Boletus edulis corresponded to 76.2%, 34.1%, 33.0%, and 4.3% of maximum daily doses for Hg, Cd, Pb, and As, respectively, indicating Hg and Cd as the primary concerns in this matrix. The study highlights a regulatory gap: EU law defines maximum levels for Cd and Hg only in fresh mushrooms and for Pb only in fresh cultivated mushrooms, leaving dried wild-grown mushrooms without enforceable limits.
Key numbers
Mean ± SD concentrations in dried mushrooms (mg/kg dry weight):
Boletus edulis (n=40):
- Hg: 3.039 ± 1.092 mg/kg
- Cd: 1.983 ± 1.145 mg/kg
- Pb: 1.156 ± 1.049 mg/kg
- As: 0.897 ± 0.469 mg/kg
Xerocomus badius (n=40):
- Hg: 0.102 ± 0.020 mg/kg
- Cd: 1.154 ± 0.596 mg/kg
- Pb: 0.928 ± 1.810 mg/kg
- As: 0.278 ± 0.108 mg/kg
Certified reference material CS-M-3 (Dried Mushroom Powder) recoveries: Hg 104%, Pb 107%, Cd 97.5%, As 105%. Precision: Hg 3.2%, Pb 2.6%, Cd 3.5%, As 3.7%.
LODs: Hg 0.003 ng/sample (AMA-254 AAS); Pb 0.16 µg/kg, Cd 0.017 µg/kg, As 0.019 µg/kg (ICP-MS).
Maximum daily dose percentages for a standard 10 g dried portion (Boletus edulis): Hg 76.2%, Cd 34.1%, Pb 33.0%, As 4.3%.
EU regulatory context: maximum Cd for mushrooms other than cultivated species is 1.0 mg/kg fresh weight; maximum Hg MRL for wild fungi excluding boletus is 0.5 mg/kg, for boletus is 0.9 mg/kg; these apply to fresh product (apply drying concentration factor before comparing to dried-weight data in this study).
Methods (brief)
80 dried mushroom samples purchased from 5 European supermarket chains (Auchan, Kaufland, Lidl, Carrefour, Tesco) in Białystok, Poland; 4–10 samples per species per supermarket. Samples homogenized mechanically and stored at −20°C. Hg measured directly by single-purpose AAS (AMA-254, Leco); dried at 600°C in oxygen atmosphere with gold amalgamator trap. Pb, Cd, As determined by ICP-MS (NexION 300D, PerkinElmer) following microwave acid mineralization (concentrated HNO3, 4-step temperature ramp 170–210°C). As measured in KED mode to correct polyatomic interferences. All concentrations expressed as dry weight. Health risk metrics: EDI, THQ, CR, HI; standard JECFA reference values for PTWI (Hg), PTMI (Cd), BMDL (As, Pb) applied.
Implications
Certification: Relevant to a mushroom ingredient page. Dried mushrooms are a commercially significant matrix in specialty food products. Boletus edulis concentrates Hg to levels approaching the PTWI with regular consumption; this makes Hg a primary analyte of concern for any product category using dried porcini. EU regulatory gap (no limits for dried wild-grown mushrooms) is a defensibility issue for any certification program addressing mushroom-containing products.
Courses: Useful for illustrating the drying-concentration effect on heavy metals and the regulatory gap for wild vs. cultivated mushrooms.
App: Boletus edulis and Xerocomus badius values can seed a dried-mushroom contamination profile, specifically for Hg (high concern), Cd (moderate), and Pb (moderate).