[NHCOLL-L:4494] Re: Mould on fossils
Anderson, Gretchen
AndersonG at CarnegieMNH.Org
Tue Sep 1 16:25:07 EDT 2009
I agree completely with John and Cathy's approach. Since mold spoors
are omni present the most effective way to approach is improved RH
management. Either through controlling the relative humidity in the
building, the room or through microclimates.
Gretchen
________________________________
From: owner-nhcoll-l at lists.yale.edu
[mailto:owner-nhcoll-l at lists.yale.edu] On Behalf Of John E Simmons
Sent: Tuesday, September 01, 2009 1:33 PM
To: Ann M Molineux
Cc: cahawks at aol.com; Sally.Shelton at sdsmt.edu; hfourie at nfi.museum;
nhcoll-l at lists.yale.edu
Subject: [NHCOLL-L:4491] Re: Mould on fossils
If you can't reduce the relative humidity below 65% in the storage area,
and fans are not an option, you can try a micro-environment approach,
such as using silica gel to lower the RH inside containers or cabinets.
A good example of the application of micro-environments can be found in
the Museum of the Inca in Cuzco, Peru. The museum is located in a large
stone building that gets very damp inside. The supply of electricity is
too unreliable to use a dehumidifier, and in any case, as Cathy Hawks
has pointed out, using a dehumidifier in this situation would most
likely damage the walls of the building by drawing moisture through the
walls at a greater rate. The museum uses the type of silica gel that
changes color when saturated. The gel is used in both storage and
exhibit cases. A small grant from a European foundation enabled the
museum to purchase a good supply of the silica gel and a small microwave
oven to dry it when it becomes saturated.
--John
On Tue, Sep 1, 2009 at 12:37 PM, Ann M Molineux <annm at austin.utexas.edu>
wrote:
Heidi's question is turning into a really interesting dialogue.
In response to John's and others excellent points I'll add a bit more
about our problems.
We used the mild bleach only at the suggestion of our mycologist
advisor and then very limited, where the fossils were shells, the shell
portions were just dusted to remove the visible signs of mold. In the
light of your feedback comments we shall return to our former practice
and rely on ethanol solution.
We were, however, advised not to encase in plastic if the
specimens had to remain in the non-HVAC environment because that can
lead to other problems. This advice did seem reasonable as our own
limited testing of T and RH inside plastic bags found an increase in
humidity levels in the plastic bags if they were zipped, again this was
in a non-HVAC environment in Texas. We have not yet tested T&RH in
completely heat sealed bags in non HVAC. We do encase in plastic in the
HVAC zone.
We were also advised to take specimens into sunlight but that
was not feasible for us for many other reasons.
Although we cannot remove all specimens to HVAC conditions, we
do remove infected individuals to isolate in our available HVAC space.
In addition we map those cabinets producing these specimens, [we have a
GIS of the entire repository] and are tracking the outbreaks to see if
there is a geographic pattern (repository position) to them or a
geological pattern (composition). These are specimens that are very
rarely handled and drawers are seldom opened. We have been using fans,
as mentioned in one response, and if the outbreak appears to be
geographic we should be able to focus those fans more effectively.
Are fans the only solution to this problem if you are unable to
move all specimens into climate controlled environments?
ann
**********************************
Ann Molineux, PhD
Curator and Collections Manager, Non-vertebrate Paleontology
Texas Natural Science Center, The University of Texas at Austin
Phone: 512-232-5384, FAX: 512-471-6090
Web: http://www.utexas.edu.tmm/npl/
Mailing addresss: Non-vertebrate Paleontology Lab, Building 122
J. J. Pickle Research Campus, 10100 Burnet Road, Austin, TX
78758-4445
From: cahawks at aol.com [mailto:cahawks at aol.com]
Sent: Tuesday, September 01, 2009 6:37 AM
To: simmons.johne at gmail.com; Ann M Molineux
Cc: Sally.Shelton at sdsmt.edu; hfourie at nfi.museum;
nhcoll-l at lists.yale.edu
Subject: Re: [NHCOLL-L:4482] Re: Mould on fossils
I concur with John. Mold, if that is what it is, is an
indication of a fundamental problem in the environment. In general, you
do not have mold on collections - certainly not widespread mold - unless
you first have mold in the building fabric. Consequently, addressing the
source of the problem (e.g., poor drainage around the building,
whatever), is important.
I, too, discourage the use of chlorine bleach on specimens.
While this will theoretically kill mold, in reality, the fungi involved
are part of the aeromycoflora and "killing" in this sense is at best a
temporary and very localized solution. Use of 95% ethanol is certainly a
better choice if HEPA vacuum still leaves you with persistent residues,
and will do far less damage to the specimens.
If the mold is pervasive in the space, you may need to consult
with a professional mycologist specializing in mold abatement in
buildings. Cleaning the specimens and leaving them in the same space
will likely result in re-contamination. Also, avoid using dehumidifiers
in subsurface spaces - these can actually exacerbate the problem if they
are causing moisture to be pulled in through a porous building fabric.
When you have a serious mold problem and there is no obvious localized
source (a leak, for instance), you probably do need an expert to help
mitigate the problem.
Cathy
-----Original Message-----
From: John E Simmons <simmons.johne at gmail. com>
To: Ann M Molineux <annm at austin.utexas.edu>
Cc: Sally.Shelton at sdsmt.edu <Sally.Shelton at sdsmt.edu>;
hfourie at nfi.museum <hfourie at nfi.museum>; nhcoll-l at lists.yale.edu
<nhcoll-l at lists.yale.edu>
Sent: Mon, Aug 31, 2009 11:03 pm
Subject: [NHCOLL-L:4482] Re: Mould on fossils
The underlying theme of all the messages that Heidi's post
prompted is that mold is an indication of a problem in the storage
environment--the appearance of mold means something has gone wrong.
Mold spores are around us all the time, but they only grow and spread as
mildew when the environmental conditions are right. The only way to
prevent mold outbreaks is by controlling the environmental conditions
the mold needs to grow. Most mold needs a relative humidity of 65% or
higher (a few species will grow at 55%) and a nutrient base. If you
have a situation where you cannot lower your RH below 65 (e.g., in the
tropics) you may be able to prevent mold growth by improving air
circulation (for example, with fans).
When a mold outbreak occurs in a collection, the first question
to ask is not how to clean it up, but rather, what caused the mold to
start growing. A mold outbreak means something has changed in the
storage environment that is not good for the collections. The sudden
appearance of mold may be the first evidence you see of more serious
drainage or leakage problems. Determining where the mold is growing can
provide clues to what is wrong and can help you establish cleanup
priorities. Mold must have a nutrient base, which is why mold growing
on leather is a much more serious problem than mold that has spread over
fossils (the mold will damage the leather faster than the fossils).
Isolate the affected specimens if you can (for example, in polyethylene
bags) or affected area, then deal with cleanup. At any rate, cleaning
up the mold won't help unless you can fix the environmental problem,
too.
I do not recommend using bleach for cleaning mold from
scientific specimens. In general, it is much safer to lightly swab the
surface of most specimens with cotton swabs dipped in 95% ethyl alcohol.
The alcohol will kill the active mold and evaporate quickly from the
surface of the specimen. Bleach will probably damage whatever it comes
in contact with, and is harder to remove. Before you clean any mold
from the surface of a specimen, make sure that your cleaning procedure
and cleaning chemicals will not cause worse damage than the mold already
has.
Good luck dealing with this problem, Heidi, and please let us
know what the solution to your problem was.
--John
John E. Simmons
Museologica
128 E. Burnside Street
Bellefonte, Pennsylvania 16823-2010
simmons.johne at gmail.com
303-681-5708
www.museologica.com <http://www.museologica.com/>
and
Adjunct Curator of Collections
Earth and Mineral Science Museum & Art Gallery
Penn State University
19 Deike Building
University Park, Pennsylvania 16802-2709
jes67 at psu.edu
On Mon, Aug 31, 2009 at 5:14 PM, Ann M Molineux
<annm at austin.utexas.edu> wrote:
Heidi,
We have also noted instances of various molds on our historic
Tertiary fossil collection located in a non-HVAC zone. Our Microbiology
department verified that it was mold and appeared to be from common
spores found in air and soil. According to them we would need specimen
sterilization and sealing within moisture free chambers to completely
protect them.
In our situation that translated into gently dusting off the
mold, light swabbing with a mild bleach solution (if the specimen could
withstand such treatment), and transfer as many as feasible to our HVAC
zone.
We have limited space in the HVAC zone but we assigned this
collection as a priority for any additional space when available.
Luckily for us some additional space may shortly be available and we are
currently searching for funding to achieve the transfer and upgrade.
None of our specimens were plant fossils but we will go ahead and move
our more important plant specimens currently stored in similar
conditions, into the HVAC zone.
I think the take home message from our viewpoint was that this
was a problem that had to be addressed if we wished to retain these very
valuable early collections.
Ann
**********************************
Ann Molineux, PhD
Curator and Collections Manager, Non-vertebrate Paleontology
Texas Natural Science Center, The Univ ersity of Texas at Austin
Phone: 512-232-5384, FAX: 512-471-6090
Web: http://www.utexas.edu.tmm/npl/
Mailing addresss: Non-vertebrate Paleontology Lab, Building 122
J. J. Pickle Research Campus, 10100 Burnet Road, Austin, TX
78758-4445
From: owner-nhcoll-l at lists.yale.edu
[mailto:owner-nhcoll-l at lists.yale.edu] On Behalf Of Shelton, Sally Y.
Sent: Monday, August 31, 2009 9:39 AM
To: Simmons, John; hfourie at nfi.museum
Cc: nhcoll-l at lists.yale.edu
Subject: [NHCOLL-L:4477] Re: Mould on fossils
I would also check to make sure that, as John says, this is not
Byne's "disease" or other mineral efflorescence. The scenario you
describe does not sound like pyrite breakdown, but does suggest the
possibility of mineral efflorescence.
I hate to engage in shameless self-promotion and am not trying
to do so, but here is a reference:
http://www.nps.gov/history/museum/publications/conserveogram/11-15.pdf.
This can affect fossil as well as Recent specimens.
Sally Y. Shelton, Collections Manager and Faculty Instructor
Museum of Geology, O'Harra 307
South Dakota School of Mines and Technology
501 E. St. Joseph
Rapid City, SD 57701
phone 605.394.2487
email Sally.Shelton at sdsmt.edu
From: owner-nhcoll-l at lists.yale.edu
[mailto:owner-nhcoll-l at lists.yale.edu] On Behalf Of John E Simmons
Sent: Monday, August 31, 2009 8:14 AM
To: hfourie at nfi.museum
Cc: nhcoll-l at lists.yale.edu
Subject: [NHCOLL-L:4476] Re: Mould on fossils
Are you positive that this is mold? Mold needs a nutrient base
to grow, as well as high humidity (>65% for most species). There are
very little nutrients on fossils, unless the mold is eating some
organic-based coating. You might be seeing a salt efflorescence or
crystallization of minerals in the rock matrix (e.g., pyrit e disease)
rather than mold--try scraping some off and looking at it under a
microscope.
--John
John E. Simmons
Museologica
128 E. Burnside Street
Bellefonte, Pennsylvania 16823-2010
simmons.johne at gmail.com
303-681-5708
www.museologica.com <http://www.museologica.com/>
and
Adjunct Curator of Collections
Earth and Mineral Science Museum & Art Gallery
Penn State University
19 Deike Building
University Park, Pennsylvania 16802-2709
jes67 at psu.edu
---------- Forwarded message ----------
From: Dr Heidi Fourie <hfourie at nfi.museum>
Date: Sat, Aug 29, 2009 at 7:36 AM
Subject: [NHCOLL-L:4474] Mould on fossils
To: nhcoll-l at lists.yale.edu
I've discovered mould growing on fossils we stored in our
basement. These are invertebrate fossils in blocks mounted in wooden
frames. Both the frame and fossil are covered in mould. The mould is
whitish grey wooly and round in pattern. It even grows on the Glyptal.
My question is, what is the safest chemical to clean this with
or is water and soap safest. The storage room that it is going to has a
very low humidity so I don't think the mould will reappear and how safe
is th e fossil plants in the same basement storeroom?
Heidi
Dr H. Fourie
Curator: Vertebrate Palaeontology
Transvaal Museum
Tel: 012 3227632
--
--
--
John E. Simmons
Museologica
128 E. Burnside Street
Bellefonte, Pennsylvania 16823-2010
simmons.johne at gmail.com
303-681-5708
www.museologica.com
and
Adjunct Curator of Collections
Earth and Mineral Science Museum & Art Gallery
Penn State University
19 Deike Building
University Park, Pennsylvania 16802-2709
jes67 at psu.edu
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.yale.edu/mailman/private/nhcoll-l/attachments/20090901/43ee8c19/attachment.html
More information about the Nhcoll-l
mailing list