Re: Re:Theroretical Drywall Question? 4

[Guest guest]

The same also applies for mycotoxin production.

Its my understanding that toxinogenic molds in general, produce mycotoxins

in order to kill other fungi.

(we are just collateral damage, as it were.) As RH rises, not only does mold

growth increase,

but toxin production increases as well.

This is why I think that some papers like the one below about " wall relative

humidity " are very important for understanding why people get ill when they

do.

There are many other other papers that show a similar relationship for

mycotoxin production and the average humidity at which the most toxins are

produced is even higher.. (one is below)

The papers show that the conditions that produce indicator molds of the

sickest buildings like stachybotrys - and then, those in which the most

*toxins* get produced, are almost always situations in which very high

relative humidity (~97% or more-) has existed for extended periods, not just

those situations in which there has been moisture ..

Sort of like rain forests for mold.. extremely competitive environments for

mold growth..

....... cut here .....

http://www.ncbi.nlm.nih.gov/pubmed/16119879

* *Bull Acad Natl Med. <javascript:AL_get(this, 'jour', 'Bull Acad Natl

Med.');> 2005 Jan;189(1):43-51; discussion

52-4.Links<javascript:PopUpMenu2_Set(Menu16119879);>

Wall relative humidity: a simple and reliable index for predicting

Stachybotrys chartarum infestation in dwellings [Article in French]

*Charpin

D*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed & Cmd=Search & Term=%22Charpin\

%20D%22%5BAuthor%5D & itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubme\

d_DiscoveryPanel.Pubmed_RVAbstractPlus>,

*Boutin-Forzano

S*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed & Cmd=Search & Term=%22Boutin-\

Forzano%20S%22%5BAuthor%5D & itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPane\

l.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus>,

*Chabbi

S*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed & Cmd=Search & Term=%22Chabbi%\

20S%22%5BAuthor%5D & itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed\

_DiscoveryPanel.Pubmed_RVAbstractPlus>,

*Dumon

H*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed & Cmd=Search & Term=%22Dumon%2\

0H%22%5BAuthor%5D & itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_\

DiscoveryPanel.Pubmed_RVAbstractPlus>,

*Charpin-Kadouch

C*<http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed & Cmd=Search & Term=%22Charpin\

-Kadouch%20C%22%5BAuthor%5D & itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPan\

el.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus>

..

Service de Pneumologie-allergologie, Hôpital Nord, Marseille.

As the indoor mold Stachybotrys chartarum (SC) has been linked to serious

health disorders, its identification in water-damaged dwellings is of utmost

importance. The aim of this work was to compare wall relative humidity (RH)

measurements with the results of mold identification studied on 458 samples

collected from 100 dwellings. Mold identification was based on direct

microscopic examination of wall samples collected by the gummed paper

technique. Mean (+/- SD) wall RH (%) was much higher (97.0 +/- 6.1) when SC

was identified (30 samples) than when other molds were identified (291

samples, 41.8 +/- 36.9) and when no molds were identified (137 samples, 38.9

+/- 34.8). There was a direct relationship between wall and room-air RH but

the scatter of results implies that the latter cannot be used as a surrogate

for the former. This study suggests that simple wall RH measurement can

serve as a reliable indicator of SC infestation of dwellings.

PMID: 16119879 [PubMed - indexed for MEDLINE]

Here is the second paper.. You can read the whole paper at this URL:

http://aem.asm.org/cgi/reprint/60/9/3421

Appl Environ Microbiol. 1994 September; 60(9): 3421-3424

Copyright © 1994, American Society for

Microbiology<http://aem.asm.org/misc/terms.shtml>.

.

*Stachybotrys atra* Growth and Toxin Production in Some Building Materials

and Fodder under Different Relative Humidities * Marjo Nikulin1,2,

-Liisa Pasanen3, Seija Berg1 and Eeva-Liisa Hintikka1,2,* *

1 National Veterinary and Food Research Institute, FIN-00231 Helsinki,

Finland

2 Department of Microbiology and Epizootology, College of Veterinary

Medicine, FIN-00581 Helsinki, Finland

3 Department of Environmental Sciences, University of Kuopio, FIN-70211

Kuopio, Finland

*ABSTRACT*

Growth of *Stachybotrys atra* and its toxin production on some building

materials and in animal fodder were studied at relative humidities ranging

from 78 to 100%. Toxins were detected by biological assays and chemical

methods. Strong growth of the fungus and presence of macrocyclic

trichothecenes, mainly satratoxins G and H, were detected on wallpaper and

gypsum boards and in hay and straw at saturation conditions. On pine panels,

*S. atra* grew well, but neither biological toxicity nor production of

macrocyclic

trichothecenes was observed.

------------------------------

*FOOTNOTES* * Corresponding author. Mailing address: National Veterinary and

Food Research Institute, P.O. Box 368, SF-00231 Helsinki, Finland. Phone:

358-0-3931 826. Fax: 358-0-3931 811.

On Sun, Jul 6, 2008 at 5:32 PM, May <jeff@...> wrote:

> Todd,

>

> The discoloration is probably just house dust that was trapped from

> small air flows by the roughness of the surfaces. (This is commonly

> seen at the edges of light-colored carpets.) If you are worried about

> it, I would agree with Carl that tape sampling would supply the answer

> to your question. Be carefeul where you send the sample. One lab

> identified soot, a possibility if you burn jar candles, as

> Stachybotrys mold!

>

> I would disagree with Carl's expert about drywall. There are millions

> of homes and commercial buildings that have been built with drywall

> where walls and ceilings do not have mold problems. Lots of folks even

> put wallpaper (with starch glue!) over plaster walls to no ill effect.

>

> Mold grows because of excess dampness, whether from leaks or high

> humidity. You don't even need paper for this to happen. Mold will grow

> in settled dust on steel and glass if the humidity is high enough. And

> dust is everywhere. This is why mold grows on foundation walls in

> basements and in carpets on concrete. Neither concrete nor plastic

> carpet fibers are biodegradable, but the dust is.

>

> So the key is to monitor the relative humidity. Therma-Stor now sells

> an " Alert " thermo-hygrometer that measures temperature and relative

> humidity (RH) and records the hours the RH is above a value that you

> set; it even rings a small alarm if the RH exceeds the preset value:

>

> http://www.thermastor.com/HA-DEH3000/HA_manual.pdf

>

> You can place one of these for a few days or weeks where you have

> concerns and see what is happening. Most molds can't grow under about

> 75% RH and don't really grow much until the RH is over 80%.

>

> Don't be confused by other advice I and others have given about

> basement RH, as

> you will hear that 50% RH is a recommended indoor value. This is

> because you want a large safety factor in the air; keep in mind that

> if the RH is 50% in the middle of a basement, it is likely to be

> higher at the cold foundation walls near the flor because RH INCREASES

> as you cool air.

>

> Some " green " builders are constructing houses with straw bales! (The

> first one was torn down after several years due to mold growth!)

>

>

>