[Nhcoll-l] Failure of plastic lids in ethanol collections

[John E Simmons]

Lance,
All plastic deteriorates over time, so what you are experiencing may not be
due to UV exposure. Even if the storage room is UV free, however, the
plastic lids may have been exposed to UV before you got them, and there are
several other factors that could cause rapid deterioration of the plastic.

The first thing to do is confirm what kind of plastic they are made from.
There will probably be a mold mark inside the lids that says something like
PE or PP or PVC. These are three different types of plastic that are
commonly used for lids, and each has its own deterioration patterns.

The lifespan of plastic lids is highly variable, depending on how they are
used, the temperature they are exposed to, light exposure (both visible and
UV), and the composition of the batch of plastic used to make the lids.
Even a normally "good" plastic such as polyethylene may have undesirable
components in it. The one thing that probably does not affect the lifespan
of the lids in any significant way is exposure to ethanol. So, first check
what the mold mark (if any) says. Let me know if there are not any mold
marks.

If the lighting is LED, the chance of it producing UV is slim, but the
emergency lights may be the culprit as you suspect. The best thing to do is
check them with a UV meter (you can purchase a good one for around $200,
perhaps less if you shop around. For example, this model is available from
a number of sellers (I did not attempt ot find the lowest price--this link
is just to show you what it looks like):
https://sperdirect.com/products/uv-light-meter-uva-uvb?currency=USD&variant=35844887183517&utm_medium=cpc&utm_source=google&utm_campaign=Google%20Shopping&stkn=73545bd6da0d&gclid=CjwKCAiAi6uvBhADEiwAWiyRdkHLwdavqvr0uJVZTX3dFYrsVsKxD6N89Yn8uEpzWIin29DS-5JBsRoC77AQAvD_BwE&gad_source=1

If you have no budget for a UV meter, check with your university's health
and safety office, or see if a local museum might have one you can borrow.
I think every museum should have a good UV meter and a good visible light
meter for monitoring collection storage and exhibition areas.

Concerning the safety lights, this is a growing problem in museums I have
worked with. The problem comes from the standards used by the safety folks
vs what is good for the collection. There is no reason to have lights
burning 24/7 in a collection storage area and there is plenty of
information in the literature about why this is bad. What you can do is ask
to have the lights changed for motion-activated safety lights, that only
come on when someone enters the room, and you can insist on having the
safety lights UV-filtered (the UV filtering does not affect the brightness
of the lights). You will need to make a good case for the importance of the
collection as well as the importance of keeping it in the dark most of the
time, and you will have to cajole and persuade the people in charge
(arguing will get you nowhere).

--John

John E. Simmons
Writer and Museum Consultant
Museologica
*and*
Investigador Asociado, Departamento de Ornitologia
Museo de Historia Natural, Universidad Nacional Mayor de San Marcos, Lima


On Fri, Mar 8, 2024 at 10:42 AM Lance McBrayer <
lancemcbrayer at georgiasouthern.edu> wrote:

> Greetings
> I have noticed a systematic failure of plastic lids on the top shelves of
> our wet collection.  The plastic is drying and cracking, or crumbling if
> the lid is pressed in the middle.  Luckily I noticed this and only had 3
> specimens dry out.  But, I'm learning the problem is
> widespread, particularly on the top shelf.
>
> These lids were replaced in about 2010, and since 2013 been have been kept
> in a new storage facility with a consistent temp in the 60-69 degree F
> range.
>
> The facility has shock-proof LED lighting that was *supposed to* emit
> little to no UV radiation.
>
> I suspect the lighting is in fact emitting UV. The problem is much less
> common on the lower shelving racks where they are 'shaded' by jars above.
> I have also guessed there may be a known 'lifespan' for plastic lids. I
> bought the lids from O Berk like many collections do in the USA.
>
>  Is anyone aware of this problem? That is:
> 1 - What have others experienced as the lifespan of plastic lids on
> specimens in 70% ethanol?
> 2 - Does anyone have suggestions as to how to remedy a UV light issue?
> There are no windows in the facility. BUT, the safety officer INSISTED on
> having 2 lights on in the room at all times in case some was in the room
> and the lights were turned off. I protested, but lost. I think it is time
> to revisit...?
>
> Any advice forward is welcomed...
> Thanks
> lm
>
> --
> Lance McBrayer
> Professor & Curator of Herpetology
> Department of Biology
> Georgia Southern University
> TEL: 912.478.0545
> *Webpage
> <https://sites.google.com/a/georgiasouthern.edu/lance-d-mcbrayer/>*
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