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Subject: Napthalene

Napthalene

From: Robyn Hodgkins <hodgkins<-a>
Date: Friday, October 10, 2014
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.
>Several garments have had no odor at all of the offending Napthalene
>until aqueous cleaning has been underway.  The sudden sublimation of
>napthalene has required heart stopping stressful adjustment to the
>wash water pH and poses a health risk.  Has anyone come across a
>pre-treatment test to determine the presence of Napthalene.

The National Museum of American Indian's (NMAI) textile conservation
lab has also experienced this large increase in mothball smell when
wet-cleaning and humidifying textiles that had slight or no mothball
odor when dry.  The problem of naphthalene residues on artifacts has
been studied at Smithsonian since around 2002.  Over the past few
years, a joint project between Smithsonian's Museum Conservation
Institute and NMAI examined this issue with naphthalene contaminated
textiles specifically.  Last month at International Council of
Museums-Committee for Conservation (ICOM-CC) we presented our latest
work to (1) quantify the concentration of naphthalene vapors and (2)
reduce the residues with a treatment we call Rapid Air Exchange.
This is detailed in the ICOM-CC preprints and three earlier
publications.

As a quick summary, we have used gas chromatography (GC) with solid
phase microextraction (SPME) sampling to measure concentrations of
naphthalene (1) when moth balls are present, (2) when textiles
exposed to naphthalene are present, and (3) at dry, ambient, and
high humidity. We found that when moth crystals are present (meaning
there's an excess of solid naphthalene), the maximum vapor
concentration depends on temperature.  At 22 deg. C, that could be
as high as 87 ppm, which is much higher than any published health
guidelines but also would be so smelly that we assume someone would
avoid working in the area. That's the concentration when the air is
saturated with naphthalene, and it didn't get any higher than that
with increased humidity.

However, when the vapor concentration is lower than the saturation
point, we found that the concentration of naphthalene vapor does go
up with humidity, and that this depended on the type of textile
fiber present. For example, with wool, our experiments showed the
vapor increased much more than with silk, cotton, or linen.

The point is that naphthalene vapors do increase with temperature
and humidity.

We rely on a wide range of health guidelines (from 15 parts per
billion up to 15 parts per million).  The odor threshold for
naphthalene is 85 ppb, but the textiles we measured usually exceed
this amount.  Our ICOM-CC publication also summarizes what we think
is the current consensus on health effects.

Our ultimate goal is to reduce naphthalene residues from artifacts
in a non-invasive way.  Our Rapid Air Exchange treatment is almost
ridiculously simple (we prefer to call it elegant).  We retrofitted
a museum storage cabinet to attach it to the NMAI conservation lab's
elephant trunk exhaust system.  We place a textile in the cabinet,
turn on the exhaust fans, and air it out rapidly.  We've been
running it for a couple days at a time.  The naphthalene smell is
significantly reduced. There is more research to be done to optimize
the treatment (like by adjusting the temperature and humidity), but
we've shown it works, and we hope it will become an accepted
treatment option.  NMAI's current procedure is to place a textile in
the extraction cabinet at least overnight or sometimes over a
weekend prior to commencing a wet-cleaning or humidification
treatment.

Here are the citations to our work.  If you can't access these,
please send an email to mciweb<-a t->si< . >edu

    Madden, O., R. Hodgkins, and S. Heald. 2014.
    "Substituting SPME for noses in the detection and quantification
    of mothball vapors from textiles in the National Museum of the
    American Indian collection".
    Preprints of the International Council of Museums Conservation
    Committee (ICOM-CC) 17th Triennial Conference, Melbourne,
    Australia, September 15-19, 2014.

    Heald, S. and O. Madden. 2011.
    "Investigations into naphthalene mitigation on museum objects".
    In 8th North American Textile Conservation Conference Preprints,
    Plying the Trades:  Pulling Together in the 21st Century, Oaxaca
    de Juarez

    Ormsby, M, J.S. Johnson, S. Heald, L. Chang, and J. Bosworth.
    2006.
    "Solid phase microextractions sampling for organic pesticide
    residues on museum collections".
    Collection Forum 20(1-2): 1-12.

    Heald, S., L. Chang, and J.S. Johnson.  2005.
    "Identification and quantification of organic pesticides on
    ethnographic textiles during treatment phases".
    In 5th North American Textile Conservation Conference Preprints,
    Conservation of Archaeological and Ethnographic Textiles, Mexico
    City 2005, 85-95.

Odile Madden
Research Materials Scientist
Smithsonian Museum Conservation Institute

Susan Heald
Senior Textile Conservator
National Museum of the American Indian, Smithsonian Institution

Robyn Hodgkins
Charles E. Culpeper Fellow, Scientific Research Department
National Gallery of Art
Washington DC


                                  ***
                  Conservation DistList Instance 28:19
                Distributed: Saturday, October 11, 2014
                       Message Id: cdl-28-19-006
                                  ***
Received on Friday, 10 October, 2014

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