[NHCOLL-L:4495] Re: Mould on fossils

Tue Sep 1 16:27:34 EDT 2009

John, As with your Cusco Museum example, the RH cannot be controlled in this building either and we have been using indicator silica gel (with a small drying oven) for specimens with known pyrite problems. We'd be interested to know the extent of the Peru problem and the number of staff required to keep it active.
We had considered creating local microclimates and keeping a 'silica gel drawer' within all enclosed cabinets (100 mostly metal) but there are almost 400 additional wooden cases with individual drawers which would need to be individually assessed.
After timing how long the gel remained active and the FTE required to achieve a reasonable silica gel exchange rate, we opted for removing as many susceptible specimens to our limited HVAC space. This approach seems to be feasible for pyrite and Byne's problems, however, the mold cases so far appear more unpredictable. We cannot yet get ahead of them!  And hence the mapping strategy.
We could try to install lowered ceiling fans (our ceiling is very high) over the cabinets and generate continuous airflow, although the building is already well-aerated. It is a large shared warehouse with doors that remain open during the daytime and vehicles drive through to various storage areas. We often wondered about those vehicle emissions and their potential effects on the specimens quite apart from the dirt particles that enter through the doorway.

ann
From: John E Simmons [mailto:simmons.johne at gmail.com]
Sent: Tuesday, September 01, 2009 12:33 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: Re: [NHCOLL-L:4482] 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<mailto: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> [mailto:cahawks at aol.com<mailto:cahawks at aol.com>]
Sent: Tuesday, September 01, 2009 6:37 AM
To: simmons.johne at gmail.com<mailto:simmons.johne at gmail.com>; Ann M Molineux
Cc: Sally.Shelton at sdsmt.edu<mailto:Sally.Shelton at sdsmt.edu>; hfourie at nfi.museum<mailto:hfourie at nfi.museum>; nhcoll-l at lists.yale.edu<mailto: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<mailto:annm at austin.utexas.edu>>
Cc: Sally.Shelton at sdsmt.edu<mailto:Sally.Shelton at sdsmt.edu> <Sally.Shelton at sdsmt.edu<mailto:Sally.Shelton at sdsmt.edu>>; hfourie at nfi.museum<mailto:hfourie at nfi.museum> <hfourie at nfi.museum<mailto:hfourie at nfi.museum>>; nhcoll-l at lists.yale.edu<mailto:nhcoll-l at lists.yale.edu> <nhcoll-l at lists.yale.edu<mailto: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<mailto: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<mailto:jes67 at psu.edu>

On Mon, Aug 31, 2009 at 5:14 PM, Ann M Molineux <annm at austin.utexas.edu<mailto: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> [mailto: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<mailto:hfourie at nfi.museum>

Cc: nhcoll-l at lists.yale.edu<mailto: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<mailto:Sally.Shelton at sdsmt.edu>

From: owner-nhcoll-l at lists.yale.edu<mailto:owner-nhcoll-l at lists.yale.edu> [mailto: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<mailto:hfourie at nfi.museum>
Cc: nhcoll-l at lists.yale.edu<mailto: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<mailto: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<mailto:jes67 at psu.edu>

---------- Forwarded message ----------
From: Dr Heidi Fourie <hfourie at nfi.museum<mailto: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<mailto: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<mailto: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<mailto:jes67 at psu.edu>
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