Napthalene

Victoria Gill <victoria.gill<-a t->endangeredheritage< . >com> writes

>I am concerned about the recent increase in garments coming in for
>treatment which have been stored with Naphthalene/mothballs.

With respect to the issue of naphthalene vapour being emitted with
an increase in relative humidity, I was going to refer you to an
observation made by Jessica Johnson, who was the senior objects
conservator at the NMAI.  Jessica first voiced her concern at the
issue of increased release of naphthalene vapour with increased
humidity.

My own doctorate research was completed last year on methods of
mitigating naphthalene from herbarium collections using heat, freeze
drying and air drying in a fume cabinet at ambient temperature and
relative humidity.  My research concluded that cellulose matrices
bind naphthalene tightly within its structure and neither heat nor
freeze drying increased release of this compound.  Herbarium paper
matrices vary largely and this also effected rate of release of
naphthalene.  My research concluded that in ambient conditions,
within the National Museum Wales herbarium (monitored to be
averaging between 45-55% RH and 18-22 deg. C) in a simple filter
fume cabinet, the average naphthalene concentration was reduced by
50% in just 48 hours.  An economical and effective method of
reducing an eye, nose and throat irritant and suspected carcinogen.
The process is not exponential and complex matrix chemistry was
observed with all three of the different techniques studied.

The NMAI and Smithsonian Institute research suggest that increasing
the RH surrounding the object and airing in a fume cabinet would
further increase release and therefore mitigation of naphthalene and
that natural history collections could benefit from further research
being carried out to modify this technique to safely reduce
naphthalene concentrations from humidity sensitive material.

Dr Victoria Purewal
Pure Conservation


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                  Conservation DistList Instance 28:21
                 Distributed: Friday, October 24, 2014
                       Message Id: cdl-28-22-002
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