Didecyldimethyl ammonium chloride

In response to Karin von Lerber's query about treating mold
contaminated textiles (Conservation DistList Instance: 21:11 Sunday,
June 17, 2007) and in view of the response, I think we have to step
back a bit about the need for residual biocides in museum
collections.

One of the problems, however, in dealing with this sort of question
online is that neither contributor mentions their local climate.  In
most climates, textiles, particularly if they are reasonable clean,
will not grow mold if the humidity is not overpoweringly high *or*
if the air is not stagnant.  One question that should have been
asked (I don't recall whether it was or not) is the conditions that
caused the mold growth in the first place.  If those conditions were
unusual for the site, then all that is required to prevent further
growth is to assure that they don't happen again.  Killing mold
spores in the air is neither achievable, nor, possibly, even
desirable.  And leaving residual chemicals in museum objects is best
not done except, perhaps, in rain forest level humidities.  It may
be that even in extreme conditions, treating case material would be
preferable to treating the objects.

At the risk of beating a dead horse (and preaching to many in the
choir), the field of conservation has gone through cycles where
conservators were using really really bad stuff (cyanide, arsenic,
etc.) in museums to kill pests.  Despite the ferocious nature of
some of them, they do not even necessarily work.  As someone pointed
out to me early in my career, insects have to eat a lot of arsenic
infested object before they die!  In any case, I would hate to see
some of this sort of thing coming back because younger conservators
may have gotten complacent about the dangers.  More than one of the
chemicals that were considered safe early in my career have been
discredited because many existing "approved" fumigation facilities
were, in fact, unsafe, because the chemicals affected the chemistry
of objects over time, or because there is continued off gassing from
the treated object.

Environmental control not necessarily of the expensive, energy
intensive kind is a better approach in avoiding problems,
particularly since it helps collection in many other ways. Non
chemical means including microwaves, freezing, and oxygen
deprivation should always be considered before chemicals, and non
residual chemicals (like alcohol) before residual ones.  This topic
is better covered in the literature than many.  Don't forget AATA
is now *free*, and you don't even have to log in to do a search.

Barbara Appelbaum
Appelbaum and Himmelstein
444 Central Park West
New York, NY  10025
212-666-4630


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                  Conservation DistList Instance 21:16
                   Distributed: Friday, July 13, 2007
                       Message Id: cdl-21-16-002
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