Overview
Zhou et al. evaluated whether chicken-manure biogas residue could be used as a substrate component for cultivating edible oyster mushrooms (Pleurotus ostreatus). The study measured cadmium, lead, mercury, and arsenic in the raw materials and in dried first-flush mushroom fruiting bodies across seven substrate treatments.
Key numbers
| Finding | Source-reported value |
|---|---|
| Highest mushroom Pb | 1.1550 +/- 0.0550 mg/kg dry weight in treatment T1 |
| Lowest mushroom Pb | 0.7850 +/- 0.0350 mg/kg dry weight in treatment T4 |
| Highest mushroom Cd | 0.1400 +/- 0.0100 mg/kg dry weight in treatment T3 |
| Lowest mushroom Cd | 0.0550 +/- 0.0000 mg/kg dry weight in treatment T6 |
| Highest mushroom Hg | 0.0074 +/- 0.0000 mg/kg dry weight in treatment T6 |
| Highest mushroom As | 0.1650 +/- 0.0050 mg/kg dry weight in treatment T6 |
| Raw biogas residue before fermentation | Cd 0.0665 +/- 0.0005 mg/kg; Pb 2.6800 +/- 0.0500; Hg 0.0225 +/- 0.0005; As 0.6800 +/- 0.1000 |
| Raw biogas residue after fermentation | Cd 0.0635 +/- 0.0015 mg/kg; Pb 2.7600 +/- 0.0300; Hg 0.0210 +/- 0.0000; As 0.6550 +/- 0.0050 |
The authors state that Pb, Cd, Hg, and As in all dried Pleurotus fruiting bodies were within China’s Green Food edible-mushroom limits for dried mushrooms: Pb 2.0 mg/kg, Cd 1.0 mg/kg, Hg 0.2 mg/kg, and As 1.0 mg/kg.
Methods (brief)
Pleurotus ostreatus (strain Huimei No. 2) was cultivated on seven substrate formulas using cottonseed hull, wheat bran, lime, water, and increasing fractions of chicken-manure biogas residue (0 to 60%). Three flushes were harvested; chemical composition and heavy metals were measured in dried first-flush fruiting bodies. Heavy metals were analyzed by Pony Testing International Group (Beijing, China); results are reported as dry-weight mg/kg. Differences among treatment means were assessed by Duncan’s multiple range test at the 95% confidence level using IBM SPSS Statistics V22.0. The paper does not name the analytical instrument or report LODs, and reports total arsenic and total mercury without speciation.
Implications
This source contributes cultivated edible-mushroom occurrence context for Pb, Cd, Hg, and total arsenic under experimental substrate conditions. It is useful for ingredient-level mushroom contamination and substrate-transfer context, but it should not be treated as routine retail-market evidence.
Related evidence
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