[NHCOLL-L:2109] PDB and naphthalene

[Tom Wendt]

Please pardon cross-posting--the reason is explained in the following 
paragraph.  This posting is fairly long.

In mid-August, I posted an inquiry about the use of PDB and 
Naphthalene in herbaria to NH-COLL.  I received a number of 
responses, mostly I think off-list, and I solicited a few more from 
specific curators.  Below, I include edited excerpts that I think 
will be of interest to some on the list.  I haven't done any further 
research, but I suspect some people on the list will have further 
comments to add.  I'm posting this to both NH-COLL and the HERBARIA 
list--the latter came into existence a few days after my post, and 
that is where I would have posted it originally if it had only 
existed at the time! I would suggest that responses be sent to the 
HERBARIA list.  A number of people contacted me saying that they were 
very interested in responses, so there is some general interest. I 
very much thank all who replied.

A general summary based on responses: PDB and naphthalene are still 
around and used, for various reasons, but mostly because: it works 
and nothing else (available and legal) seems to in particular 
situations.  Those who don't use it have to deal with it occasionally 
in loans, returned loans, incoming exchange, etc., and although at 
times a hassle, it's the price of doing business, and other problems 
are more serious or pressing.  Several curators essentially take on 
the "burden" themselves to avoid possible health problems for or 
complaints from herbarium workers/student workers/etc.  One further 
point of interest, though (or perhaps just coincidence, or different 
circumstances):  I received emails from two curators wondering if the 
shipment that generated my original email was from them.  In one 
case, it indeed was (using naphthalene--my error in original 
posting); in the other case (using PDB), we don't even smell fumes on 
returned material.  So overdosing with PDB or naphthalene may be the 
real problem; or maybe it's PDB versus naphthalene.

Tom Wendt

******************************

My original posting was:
We recently received a return of loaned herbarium specimens from an 
herbarium that obviously uses PDB as part of their insect-control 
protocol.  This has caused a fair amount of work and bother here as 
we try to allow the specimens to "off-fume" before refiling.  I was 
of the impression that almost no major herbaria still use PDB (or 
naphthalene, either) as a fumigant, and that it was quite discouraged 
for health reasons (as well as only moderate efficacy at best).  Are 
there other of you out there who use it routinely?  Any who fairly 
commonly have the problem of returned material with PDB fumes? 
Comments?

 From Travis Marsico (Univ. Arkansas Herbarium):
...at my alma mater, Arkansas Tech University, the curator of the 
herbarium (a relatively small-- maybe 20,000 specimens--but active 
herbarium)...still uses moth balls and swears by them.  As you can 
imagine, I hated working in the collections there.  I don't know if 
he likes the smell, or simply has no regard for his health, but even 
though I tried to find out why he still uses the method, the best I 
could come up with is "it works".
My hope is that the use of moth balls will soon fade out 
entirely--unlike the smell!!!

 From Susan Woodward (Royal Ontario Museum):
Although I do not permit use of either chemical IN the collection,
napthelene is routinely used in the field to protect study skins from
insect pests.  I designed and built a mobile cabinet that permits us lay
out skins on mesh drawers to off-gassing of the fumes; an "elephant
trunk" vents the air from the top of the unit and 2 screened slots at
the base permit the introduction of "clean" ambient air.  I presented
it's design and use as a poster at the SPNHC meetings in Montreal last
year.
I know that many insect collections still actively use nasties because
their specimens are so vulnerable to dermestid attack.  I suspect many
herbaria do as well.

 From Ann Pinzl (Carson City, Nevada):
     ...V. Purewal (Collection Forum
2001 16(1-2);77-86) reports herbaria using PDB - however from her table it
is unclear if these are "major" herbaria (maybe mostly European as she is
located in Wales) or if the number "6" reflects literature references or
results from her (contemporary) survey [I suspect the latter].  The only
other chemical to score higher (with a 7) was Naphthalene.  So it is still
in use - we herbarium folk tend to be conservative in our practices and do
not necessarily embrace change too much (but then I would think the other
disciplines, e.g. mammalogy, paleo, are also mired in their own time warps
of practices).
     By the way, I have been told (and don't know how valid this evaluation
is) that if you can smell it, you've already overdosed the situation, and I
know at my previous place of employment, the practice (at least for the
zoological material) had been to keep adding PDB until the smell drove you
out of the room.
     So, I imagine that PDB fumeswill be around for a good while yet.


 From Bob Glotzhober (Ohio Historical Society):
We still use PDB, though in small amounts.  We have not been able to 
find a reasonable alternative, and have not the staff to run 
specimens through a freezer or to fund anoxic cabinets, etc.  We 
typically use it more like a fumigant for any new material, or any 
incoming material, and rarely add it to existing material unless we 
suspect a problem.

 From Mike Vincent (Miami University of Ohio):
We have not used PDB for over 20 years.  We have had no insect 
infestations since we started using naphthalene about 15 years ago, 
while we had many before that while using "No-Pest strips."

 From Emily Wood (Gray Herbarium, Harvard):
We deal with a lot of places in the Old World for exchange as well as 
loans, and several of them come to mind when I think of that lovely 
PDB/naphthalene smell!  It is on the way out in many places, but 
habits die hard, I think, and for some herbaria there may not be many 
viable alternatives except for chemicals that are even worse.
When a shipment is returned that has mothballs in it (or, even more 
insidious, moth *crystals*), the first thing I do is let the 
curatorial staff member responsible that I will be happy to unpack it 
myself -- and I often do, by choice, even if they say "it's okay". 
(I do have a respirator that was fitted for my use by our EHS dept. 
many years ago, but I think I've used it only once.)  The mothballs 
are easy enough, as we just toss them into a ziploc as we're 
unpacking and usually get most of them.  The residue seems to 
sublimate pretty quickly, relatively speaking, and if it's a matter 
of letting material air out a few weeks before we put it away, no 
biggie.  Crystals impregnate the specimens much more thoroughly and 
have to be shaken out of every specimen (I'm thinking exchange, 
mostly), so they're a pain, but there are still places that use them, 
and if we want their material we have to pay the "price".
To my knowledge, we have never considered NOT doing business with a 
place that uses PDB or naphthalene....I personally am not too 
concerned about the hazard to me, and I think I do what I can to 
minimize exposure for those who work with me.  There is less I can do 
to minimize exposure to specimens dipped in mercuric-chloride over 
the last several hundred years, or to specimens treated with 
who-knows-what, as the latter don't advertise themselves (save 
mottled paper) nearly as well as PDB.

 From Rich Rabeler, Univ. of Michigan Herbarium:
In the vascular side of MICH we stopped using PDB many years ago.  We are
now using the AC and humidity controls to try to accomplish protection from
bugs.  It was used heavily in our fungus collection and it is still in many
of the collections.  We don't have the resources to go through the entire
collection and remove it, but are doing so as specimens are either databased
or sent out on loan.  We try to maintain continual fresh air exchange in the
collection area to make sure the outgasing fumes don't build up.
We rarely get material that has been "mothballed".  I would follow Emily on
her comments as to what I'd suggest (and what we would likely do) when it
does arise.
One thing that we as a herbarium community don't do is communicate to others
about procedures we would not like our specimens subjected to.  I do
remember one loan document that crossed my desk several years ago that
stated that this herbarium (can't recall which one) did not want its
specimens to come in contact with PDB since it would soften the adhesive
holding the plant to the sheet.   Should we start thinking along those
lines?
[Later note added about fungus collection: We do have some fragile specimens
  that are encased in Naph -it may be more damaging to remove it than to slowly
let it sublimate away.]

 From Barbara Ertter (Univ. of California at Berkeley Herbarium):
Although we also phased out our previously heavy use of PDB because 
of potential health (and liability) concerns, I don't consider either 
the still-lingering odor or input from returned specimens to be a 
high priority concern.  Not only because of all the higher priority 
battles to fight, but because my research into fumigants years ago 
indicated that the human nose is extremely sensitive to PDB and 
napthalene, so that detectable quantities do not necessarily 
translate into anything that can affect health except in particularly 
sensitive individuals.  Which is why I would also do as Emily does 
and not require a sensitive or reluctant staff member to deal with a 
reeking loan return, though we also bring up the lingering PDB odor 
as something to disclose to prospective candidates when we interview 
new staff members in the first place.

 From Kent Perkins (Univ. of Florida Herbarium):
There are quite a few herbaria still using PDB and napthalene. 
Insect pests are still a problem although I think some curators would 
like to believe it won't happen in their collection.  I know of two 
institutions that had severe outbreaks in the last few years.  I hear 
Lucinda McDade gave a talk on the big problems at PH at the Mobile 
meetings.
We had a fairly good situation in Rolfs Hall until we moved in 1997. 
I had mostly phased out PDB.  UF Pest Control periodically fogged the 
collection with a synthetic pyrethroid combined with methoprene, a 
juvenile hormone.  I think the hormone really worked well.  Plus, I 
could keep the environment fairly cold and dry.
Prior to using the pyrethroid we used drione (silica and pyrethrum). 
That really worked well but we had problems with eye irritation and 
one person had an allergic reaction to it.
We moved to the FLMNH building in Oct. 1997.  Our main collection is 
compactorized in a room that is surrounded by landscaped berms 
(sunken in the ground.  The humidity in the room was 60%+ at times 
and the ceiling would occasionally drip condensation.  All of a 
sudden we had a huge outbreak of book lice in the collection.  They 
do cause damage to flowers and we feel lucky we caught them fairly 
soon on as they are hard to spot.  I tried using pyrethrum spray but 
got no results at all.  Pest control suggested we use PDB. It works. 
We had Environmental Health check the levels and told us they were 
within EPA limits.
We've gotten a new HVAC system in that room now but to be safe rotate 
low levels of PDB through the collection.
Our other areas of specimen storage don't have the new system. These 
areas are not as humid.   To be safe we still use low levels there 
too.
Our pest control unit won't use methoprene anymore for some reason 
and advises us that PDB is our only effective deterrent / control for 
cigarette beetles and book lice.  If you know of any alternatives I 
would appreciate your insight.
Of course we do the standard freezing of all incoming shipments and 
not leaving specimens out overnight.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.yale.edu/mailman/private/nhcoll-l/attachments/20031020/f3bcb571/attachment.html