Zero Nowhere said:

Dont worry man!

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Quote:

A research team from the University of Castilla-La Mancha (UCLM) has analysed the presence of heavy metals in 12 species of mushroom collected from non-contaminated natural areas, and has found that the levels vary depending on the type of mushroom. The results of the study, which appears this month in the journal Biometals, show that the largest quantities of lead and neodymium are found in chanterelles.

"The aim was to find out if there is a connection between the concentrations of specific heavy metals detected in the mushrooms, based on three factors: the type of substrate, the study area and the species of mushroom. The third was the determining factor", explains Juan Antonio Campos, principal author of the study and researcher at the Department of Crop Production and Agricultural Technology at UCLM.

The researchers have analysed the presence of lead (Pb), neodymium (Nd), thorium (Th) and uranium (U) in a hundred samples of 12 different species of common mushroom, both edible and non-edible, collected from non-contaminated zones in the Ciudad Real province. They were collected from wooded areas comprising Holm oak, Kermes oak, Pyrenean oak, Pine and Cistus.

The results of the study, published this month in the journal Biometals, reveal that there are 'considerable' quantities of the four metals in all the species examined, as well as significant differences in the capacity for accumulation of these elements depending on the species.

The analysis of these heavy metals - which can be toxic to humans - was carried out using X-ray fluorescence spectometry, a technique that enables a sample's composition to be detected and quantified using X-rays.

The highest levels of neodymium (7.1 micrograms/gram) and lead (4.86 μg/g) were found in the chanterelle (Cantharellus cibarius), a mushroom widely used in European cuisine. This mushroom grows in the shadow of Holm oaks, Cork oaks and oaks, and is ectomycorrhizal (it clings to the external roots of plants to exchange nutrients), thereby it has direct contact with the mineral particles of the soil.

For their part, thorium and uranium accumulated mostly in Hypholoma fasciculare, with concentrations of 3.63 and 4.13 μg/g, respectively, "despite being a species that lives on fallen tree trunks and is isolated from the mineral substances of the soil".

The scientists found no significant differences in the metal levels when comparing mushrooms collected from different substrates, habitats and localisations. The only exception was with thorium, which accumulates more in mushrooms which grow on wood (such as Hypholoma fasciculare or Gymnopilus spectabilis) than in those which have contact with the organic material of the soil (Tricoloma ustaloides and Pisolithus arrhizus).

New lines of research

To confirm that the type of substrate can take on a more important role than reflected in the study, the researchers have embarked on a new project in which they will analyse the presence of 19 chemical elements (toxic and non-toxic) in 15 species of edible mushroom.

"The real issue is that those mushrooms that form ectomycorrhizae are specially adapted to absorb chemical elements from the mineral particles of the soil, and give them to the plant. This is their contribution to symbiosis, and, the more effective they are in providing nutritional elements to the plant, the closer their connection to it, and the more sugars from photosynthesis they can access, which is what they are ultimately looking for", explains Juan Antonio Campos.

This type of mushroom carries out an indiscriminate acid attack on the mineral particles of the soil and absorbs elements in quantities relative to the mineralogical composition of the soil. "In some contaminated soils, or those with particular mineralogical characteristics, the mushrooms collected can reach such high concentrations of toxic elements that their consumption would be unadvisable", reveals the researcher.

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References.

Juan A. Campos, Noel A. Tejera y Carlos J. Sánchez. "Substrate role in the accumulation of heavy metals in sporocarps of wild fungi". Biometals 22 (5): 835-841, octubre de 2009.

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Quote:

Resistance levels to heavy metals in 21 mushrooms obtained mainly from Japan, but also from Thailand, were tested. The mushrooms were 7 Pleurotus species, 2 Pycnoporus and Pholiota species and one each of Agrocybe, Cryptoporus, Coriolus, Inonotus, Lampteromyces, Grifola, Flammulina, Lyophyllum, Agaricus, and Polyporus species. The Pleurotus species strains showed higher resistance to the heavy metals, copper, cadmium, zinc, nickel, cobalt, mercury than the other species. Pleurotus ostreatus exhibited the highest resistance to all these heavy metals.

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Quote:

The FDA has established the current IRL at 3 µg per day for children and 12.5 µg per day for adults. These levels allow for differences across populations and are set nearly ten-times less than the actual amount of intake from food required to reach the CDC’s blood reference level

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Take Lycoperdon perlatum, which appears to accumulate these metals at a much higher rate. One study shows a concentration of ~3.5 mg/kg in samples grown near a metal smelting facility (0.5 km). At that (high) concentration, you need to eat 280 grams of contaminated puffballs in a day to reach the IRL.

http://www.nipne.ro/rjp/2011_56_1-2/0257_0265.pdf

Grow oysters, don't sweat this stuff. I've been seeing a great deal of alarmist posting from you recently. No offence intended.

Whitelighter said:

Also, if you think about what you're saying about near a "concentrated source" I would think that the manure is the highest concentration source of toxic things and heavy metals because it's what the animal is eliminating, because of of, well, it's toxicity.

So if a horse is fed a bunch of crap and chemicals, the manure will most definitely be highly contaminated.

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teladi said:

Secondly, those heavy metals are not available in their elemental form, and as such have radically different effects.

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Quote:

Heavy metals in animal manures or in sludge
(bio solids) may be found in the form of metal ions
or of inorganic or organic complexes. In soil there
are the same metal forms which are also adsorbed to
the surface of clay minerals or clay-humus
complexes.

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https://pdfs.semanticscholar.org/c697/d925c94edd64f4ffb8d511e0d86d44c101e0.pdf


Still, none of this is anything I would ever worry about.

juniperus said:

teladi said:

Secondly, those heavy metals are not available in their elemental form, and as such have radically different effects.

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Quote:

Heavy metals in animal manures or in sludge
(bio solids) may be found in the form of metal ions
or of inorganic or organic complexes. In soil there
are the same metal forms which are also adsorbed to
the surface of clay minerals or clay-humus
complexes.

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https://pdfs.semanticscholar.org/c697/d925c94edd64f4ffb8d511e0d86d44c101e0.pdf


Still, none of this is anything I would ever worry about.

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Mr Piggy said:

Yes, Dr Jenny Mccarthy told us so.

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And that's not even to mention the dreaded cow pock

teladi said:

If you're this scared of heavy metals, you're going to freak out when you learn about Xenoestrogens. And that some fungi produce them as mycotoxins - Mycoestrogen - many of which are found in stored grains.

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Oh no LOL- Mr. Paranoid(me) has another thing to research and freak out about.. LOL.


Thanks Jk.

I will be looking into that.