Re:stachybotrys - spore testing of air fails to show it - new paper sho

[Guest guest]

Quack,

Most indoor Stachybotrys mold colonies are on drywall paper, the majority of

which are within wall cavities. There are few mechanisms for dispersal other

than the occasional rodent disturbance. (I often find mites feeding on

Stachybotrys but I don't think that they would be a great source of spore

aerosol.)

The most common source of Stachybotrys spore distribution into the indoor

environment is disperal either by individuals such as careless contractors

(who remove the drywall) or unknowing homeowners (who disturb the mold when

it is on the finish side of a wall). The reservoir for these mechanically

aerosolized and then settled spores is often carpeting. The spores are not

pulverized but most often remain intact, though there are occasionally

damaged spores.

Stachybotrys hyphae are also rather sturdy and occur in large fragments that

are not readily aerosolized or inhaled.

I do not recall that the microparticles alluded to in the Straus study of

moldy ceiling tiles were ever identified but in typical indoor environments

most of such particles would probably be associated with the substrate for

the mold and not the mold itself.

For example, gypsum in proximity to drywall paper with mold growth could

easily acquire allergenic enzymes. The dust from this gypsum could serve as

respirable, surrogate allergen. If toxigenic growth is present, gypsum dust

could also acquire mold metabolites such as mycotoxins excreted into the

substrate.

Mold does not grow through the gypsum and the common growth in the paper at

both sides of a section of drywall is the result of independent

colonization. Thus only the gypsum and paper at the surface have the

potential to become surrogates.

To get an idea of how difficult it is to aerosolize Stachybotrys, consider

this. I took an air sample in a kitchen sink-base cabinet in which all the

exposed, unpainted drywall paper at the back of the cabinet was black with

Stachybotrys growth (from a long-term leak). I did not observe a single

Stachybotrys spore in the six-minute air sample, even after opening and

closing the cabinet door a few times. Of course, had I disturbed the mold,

the results would have been very different.

C. May, M.A., CIAQP

May Indoor Air Investigations LLC

3 Tolkien Lane

Tyngsborough, MA 01879

617-354-1055

www.mayindoorair.com

www.myhouseiskillingme.com

>stachybotrys - spore testing of air fails to show it - new paper sho

>Posted by: " LiveSimply " quackadillian@...

>Date: Sun Sep 23, 2007 7:55 pm ((PDT))

>I just found this..

>My reading of this is that after the initial first sporulation in

>which 1% of the sores fly off, the remaining 99% of the spores just

>stay on the surface of the mold colony.. remaining toxic for a long

>time, until they completely dry out and get pulverized into

>(microscopically) unrecognizable but toxic dust, with the strong

>potential of making people very ill..

>Fungal Genet Biol. 2007 Jul;44(7):641-7. Epub 2006 Dec 24.

>Biomechanics of conidial dispersal in the toxic mold Stachybotrys

>chartarum.

>Tucker K, Stolze JL, Kennedy AH, Money NP.

>Department of Botany, Miami University, Oxford, OH 45056, USA.

>Conidial dispersal in Stachybotrys chartarum in response to

>low-velocity airflow was studied using a microflow apparatus. The

>maximum rate of spore release occurred during the first 5 min of

>airflow, followed by a dramatic reduction in dispersal that left more

>than 99% of the conidia attached to their conidiophores.

>Micromanipulation of undisturbed colonies showed that micronewton

>(microN) forces were needed to dislodge spore clusters from their

>supporting conidiophores. Calculations show that airspeeds that

>normally prevail in the indoor environment disturb colonies with

>forces that are 1000-fold lower, in the nanonewton (nN) range.

>Low-velocity airflow does not, therefore, cause sufficient disturbance

>to disperse a large proportion of the conidia of S. chartarum.

[Guest guest]

Jeff,

Thank you for responding to my post!

Yes thats what I was getting at. If stachy is found in any kind of testing

that should give everyone involved with the job a heads up that they need to

be EXTRA careful with spore test results because the possibility of false

negatives with stachy is much higher than the possibility of accurate

results, it seems. Unless there are multiple methods of testing being done

that hopefully include ERMI and spore testing done with

aggressive efforts to disturb spores to find them. (banging on walls, etc.)

I'm not a mycologist and some of the terms in these papers I don't

understand but I think the 99% figure was pretty clear.

99% of the mold was STILL THERE with no spores showing up in the tests. And

you think that the only way they are going to get revealed to a spore trap

test is IF a mouse scurrys through the wall at exactly the right moment

(right before the air pump that draws air into the spore trap is running,

assuming that the air that the trap sucks up is able to gather it)

IMO its like a smack on the side of the head to everyone when we see this

just how few stachy spores make it out into the air to be picked up by spore

testing. But they can still be there.

Thank you!

Would you mind if I forward that assessment of the non-efficacy of spore

trap testing for stachybotrys to some public officials I've been trying to

convince of how spore trap tests are inadequate for clearance testing of

stachy situations.