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

Fri Mar 8 14:38:47 EST 2024

John and Rob have stated the challenge very eloquently and thoroughly.  It is most important to understand that any light (UV, Visible and IR) will cause deterioration to many organic objects, including plastic. With LED lights we can eliminate the UV and the IR.  Testing with a light meter is often the easiest way to do it.  When you test - check both the UV and the visible levels.  As already mentioned, damage because of light exposure is directly related by the length of the exposure (cumulative) and by how close the object (in this case - the lids) is to the lights. The closer the object is to the light the more intense the light is and the more damage there will be.

Good Luck!
Gretchen

-----Original Message-----
From: Nhcoll-l <nhcoll-l-bounces at mailman.yale.edu> On Behalf Of Simon Moore
Sent: Friday, March 8, 2024 12:19 PM
To: robert Waller <rw at protectheritage.com>
Cc: NHCOLL-new <nhcoll-l at mailman.yale.edu>
Subject: Re: [Nhcoll-l] Failure of plastic lids in ethanol collections

CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe.

Oh yes, this is what (I suspect) prevented the Danish jar company from producing more of their otherwise very convenient-to-use jars! Some may disagree about this! These were PP lids and suffered from exactly the problems you describe.  One of their formulations however, worked very well and I still have specimens in ethanol stored successfully in the jars since the early 1990s with hardly any evaporation or plastic degradation.

Otherwise, John and Rob have covered the issue and I expect there will be others who will have their say.

With all good wishes, Simon

Simon Moore MIScT, RSci, FLS, ACR
Conservator of Natural Sciences and Cutlery Historian.

https://linkprotect.cudasvc.com/url?a=https%3a%2f%2fwww.natural-history-conservation.com&c=E,1,ryUxwOEkf0QEKiazAE5Gd_AsjIl1-vKamH3kHFtF-OhQSt1yleTVZdgTIaBXGyD1e-_ltwF6kDCcfb4-Pj4B-io9fsAnh_kbVMSHJN_xODadcZWhczA,&typo=1

> On 8 Mar 2024, at 17:12, Robert Waller <rw at protectheritage.com> wrote:
>
> John offers lots of good advice here but let me add a little to it. These common plastics (like PE or PP or PVC) are all subject to light induced oxidation, not just UV light but visible light as well. They will all contain antioxidants within their formulation to reduce photooxidation rates but some of those may be extracted into ethanol solutions over time. It is important, when new lighting is installed or lights changed, to ensure they are low in UV and John’s recommendation to just borrow a meter for a few hours to do that is great advice. Still, I expect that the main issue is the dose (combination of intensity and duration) of visible light received by lids. I suggest laying a light meter on the top of a selection of top shelf lids to obtain a range of lux (or foot candle) measurements, then do the same for lids on the lowest shelves. Note it is important to have the light sensor in a plane parallel to the lids and try to not block light with parts of your body. I suspect that the difference in light intensities will be on the order of at least 10 to 1, maybe even 100 to 1. It is fair to first assume that lid degradation is roughly linearly proportional to light dose. Therefore, where we see a light intensity difference of 500 lux top shelf to 50 lux bottom shelf, we might first assume that the lid degradation seen in 3 years on the top shelf would take 30 years on the bottom shelf. Unfortunately, your collection provides what is termed a “natural experiment” for observing light damage rates.
>  At the Canadian Museum of Nature, we encountered a similar problem with one bank of lights on emergency power and on 24/7 for emergency egress. It was challenging and costly but we were able to rewire the lights so all lights would be turned off when the rooms were unoccupied. To avoid having someone left in any room, or back part of a room, when the lights were turned off by someone else leaving, the room lights would blink repeatedly to signal the need for the remaining person to turn the lights on again. I think they had 30 minutes to accomplish turning the lights on again. It is not just damage to plastic lids, but unnecessary bleaching of fluid preserved specimens that was a concern to us. We were able to demonstrate that not just colours, but even patterns could be lost to light exposure over time, and that this needless (i.e., not use-related risk) was a substantial risk (expected loss of value) to our collections over time. You may want to contact Luci Cipera, Conservator at CMN for more information and a link to the CMN’s excellent facility manager, Martin Leclerc, who worked hard with us to resolve the issue.
>  Best,
> Rob Waller
>  From: Nhcoll-l <nhcoll-l-bounces at mailman.yale.edu> On Behalf Of John
> E Simmons
> Sent: Friday, March 8, 2024 11:22 AM
> To: Lance McBrayer <lancemcbrayer at georgiasouthern.edu>
> Cc: NHCOLL-new <nhcoll-l at mailman.yale.edu>
> Subject: Re: [Nhcoll-l] Failure of plastic lids in ethanol collections
> 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://linkprotect.cudasvc.com/url?a=https%3a%2f%2fsperdirect.com%2fp
> roducts%2fuv-light-meter-uva-uvb%3fcurrency%3dUSD%26variant%3d35844887
> 183517%26utm_medium%3dcpc%26utm_source%3dgoogle%26utm_campaign%3dGoogl
> e%2520Shopping%26stkn%3d73545bd6da0d%26gclid%3dCjwKCAiAi6uvBhADEiwAWiy
> RdkHLwdavqvr0uJVZTX3dFYrsVsKxD6N89Yn8uEpzWIin29DS-5JBsRoC77AQAvD_BwE%2
> 6gad_source%3d1&c=E,1,VEadjhYguAbbsEBTSHK-CmvBAHvY3xWh8vUIM1SMe8j4dCTg
> 0RIRkHPNltzEfaPPQ6NH7PXjA0ksHuxw3WuschVB5f40q9jWMizXPsVMPadHVY6w&typo=
> 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
> _______________________________________________
> Nhcoll-l mailing list
> Nhcoll-l at mailman.yale.edu
> https://mailman.yale.edu/mailman/listinfo/nhcoll-l
>
> _______________________________________________
> NHCOLL-L is brought to you by the Society for the Preservation of
> Natural History Collections (SPNHC), an international society whose
> mission is to improve the preservation, conservation and management of
> natural history collections to ensure their continuing value to
> society. See https://linkprotect.cudasvc.com/url?a=http%3a%2f%2fwww.spnhc.org&c=E,1,bwf1TlVzS7SQzBDisUmYNmUX_lgL3RnPuAixeyDleyDNDLNjVbvlxigdvuTUJMtCy7xL_Oe9eCpc_zBbvXfX5qKgSJvQpNvzlhRF7W5PfWhfxUU,&typo=1 for membership information.
> Advertising on NH-COLL-L is inappropriate.
> _______________________________________________
> Nhcoll-l mailing list
> Nhcoll-l at mailman.yale.edu
> https://mailman.yale.edu/mailman/listinfo/nhcoll-l
>
> _______________________________________________
> NHCOLL-L is brought to you by the Society for the Preservation of
> Natural History Collections (SPNHC), an international society whose
> mission is to improve the preservation, conservation and management of
> natural history collections to ensure their continuing value to
> society. See https://linkprotect.cudasvc.com/url?a=http%3a%2f%2fwww.spnhc.org&c=E,1,lhkamN7TS3uHAISZz3iMZcbyrx4NPCUuTll5bOqBwXY3Hul2gVNy9UxxiQsO4CpU4548kCpAhqWtfnQ-ZqHAqWzcyHPcnaNUtnvp9ZSF8FKHG-28o2I2KYeSfg,,&typo=1 for membership information.
> Advertising on NH-COLL-L is inappropriate.

_______________________________________________
Nhcoll-l mailing list
Nhcoll-l at mailman.yale.edu
https://mailman.yale.edu/mailman/listinfo/nhcoll-l

_______________________________________________
NHCOLL-L is brought to you by the Society for the Preservation of Natural History Collections (SPNHC), an international society whose mission is to improve the preservation, conservation and management of natural history collections to ensure their continuing value to society. See https://linkprotect.cudasvc.com/url?a=http%3a%2f%2fwww.spnhc.org&c=E,1,gyhmpUFOypvIrU0xKarsdma_f0ZU4UT9kRTl7vVx2P0-un5TfPkzW5fOIFhnwB-lMsWahY2SZnuHkvw-vNGh1WMPmJIDK8zD1dWYXuzMPwnPqgu39g,,&typo=1 for membership information.
Advertising on NH-COLL-L is inappropriate.

The information contained in this message and/or attachments is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from any system and destroy any copies. Any views expressed in this message are those of the individual sender.