# Do you know if plastic is safe for regular use in frog tanks?



## earthfrog (May 18, 2008)

Many of you have heard already that vinyl, such as that used in shower curtains and flexible sports drink bottles, can be toxic to humans. It can be identified as that 'strong plastic smell'. What you are actually smelling is the plastic emitting hazardous compounds. We also are aware that even polycarbonate plastic is not entirely safe. Neoprene, a synthetic rubber, is used in creating chemical-resistant gloves, has been shown to mutate tads almost instantly upon contact 
I have noticed that film canister also have a 'plastic smell', but they are not made of the same type of plastic. Further studies suggest that plastics and other related products are not all that wholesome. 
Can anyone shed some light on this subject in lieu of the long-term of our frogs? We can all benefit from what you have to offer---give your opinions supported by studies where possible. Please cast your vote and make your voice heard as well.


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## earthfrog (May 18, 2008)

Based on what I know about plastic, I will try to limit its use in the vivarium. I do have a plastic drainage tube in the viv, but it is sequestered down low where the frogs typically do not go since they're arboreal. 
Also, I will not handle frog eggs with rubber/neoprene gloves since they each exude a harmful chemical (different to each susbstance) which may be readily absorbed into the egg's membrane. 
Any other thoughts, studies or findings that anyone can share?


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## pl259 (Feb 27, 2006)

I also try to minimize the use of synthetic materials. As a note, there was a report a while back about the negative effect latex had on tadpole development.


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## Ed (Sep 19, 2004)

Do you have a referance for the supposed toxicity of neoprene? I am unaware of any referances supporting toxicity from use of neoprene but I am aware that a lot of lab materials used with tadpoles are made from neoprene. I am aware of severe toxicity reports for vinyl and latex but not neoprene.

Ed


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## 64physhy (Jul 2, 2009)

I would think anything that's harmful to us would be harmful to frogs. As far a water bottles, or any plastic used with food or drinks, the toxins are released when they are heated, like if you leave a bottle of water in your car, or heat something wrapped in plastic in the microwave. When I went to Costa Rica, I found quite a few things, including frogs, living in water bottles, tires, etc.


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## ravengritz (Mar 2, 2009)

I would like to vote for "that depends". Whether plastic is safe for frogs depends on the type of plastic, what stressors it has undergone and how it is used. I will say that I've moved all of my fruit fly culturing to glass and am replacing my petri dishes with glass. It's much easier to sanitize and there are no contamination concerns.


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## earthfrog (May 18, 2008)

Ed said:


> Do you have a referance for the supposed toxicity of neoprene? I am unaware of any referances supporting toxicity from use of neoprene but I am aware that a lot of lab materials used with tadpoles are made from neoprene. I am aware of severe toxicity reports for vinyl and latex but not neoprene.
> 
> Ed


Sure thing---here you go. I'm sure there are other articles, but I have to go prepare for my childbirth class tonight---as a general rule, I've found that plastics, natural or synthetic rubber compounds, elastomers/polymers, vinyl, derivatives of plastics or chemical 'brothers' to them are all relatively unstable and produce varying levels of toxic effects when exposed to organic matter.

Chloroprene, the base component in polychloroprene, is a suspected carcinogenic factor.

From the following article, it is suggested that neoprene, short for polychloroprene, has DNA-adducting tendencies, which can cause harmful mutations similar to the ones described in the thread below:

http://www.colby.edu/chemistry/CUSRR/CUSRRprogram.pdf

Do a search within the document for 'polychloroprene':

Session ID:
1-7
Abstract Title:
DNA Cross-Linking Activity of (1-Chloroethenyl) Oxirane
with Synthetic DNA Oligomers
Presenting Author: Other Authors:
Brian A. Wadugu (’09) Rebecca J. Rowe, and Julie T. Millard
Department:
Department of Chemistry, Colby College, Waterville, ME
Abstract:
"Chloroprene is a large-scale industrial chemical used in the manufacture of polychloroprene, a solvent-resistant elastomer. Correlation between occupational exposure to chloroprene and lung cancer has been noted, leading to the compound's classification as a possible human carcinogen.
Chloroprene metabolites have been implicated in its carcinogenicity, with evidence that the bifunctional metabolite (1-chloroethenyl)oxirane forms DNA adducts. Because structurally similar compounds such as epichlorohydrin form DNA interstrand cross-links, we are investigating possible DNA cross-linking by (1-chloroethenyl)oxirane (COX). Following synthesis of this metabolite, we used denaturing polyacrylamide gel electrophoresis to investigate its DNA cross-linking. Our data suggest that COX cross-links DNA and is more efficient at lower pH."

Here is another related thread on Nitrile, vinyl and latex from 'days past':

http://www.dendroboard.com/forum/sc...fect-latex-nitrile-vinyl-gloves-tadpoles.html


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## DCreptiles (Jan 26, 2009)

i use small stackable plastic containers for all herps not just PDF's and of course some are in there longer then others but from personal expierence i have never had an issue with using them.

-Derek


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## Ed (Sep 19, 2004)

Hi Susan,

My background is in biochem and the article you provided indicates a toxicity to the ingredient used to make neoprene not the actual neoprene itself. As a polymerized item, the neoprene does not cause those toxicities of the monomer used to make the neoprene. 

The article can't be used as a reason to say neoprene is toxic. 

Ed


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## earthfrog (May 18, 2008)

Ed said:


> Hi Susan,
> 
> My background is in biochem and the article you provided indicates a toxicity to the ingredient used to make neoprene not the actual neoprene itself. As a polymerized item, the neoprene does not cause those toxicities of the monomer used to make the neoprene.
> 
> ...


Thanks for letting me know---I was wondering about that myself based upon that article. I had only a few minutes to look, but I'll post more when I have time. (My background is in natural childbirth education, so I had to go prepare for my class earlier and didn't have sufficient time to dig...) My hypothesis is that when man alters a natural substance, it is not entirely stable afterwards so there may often be unseen or subtle effects as a result. That will be nearly impossible to prove, obviously...
Do you have a study showing the 'harmlessness' or inert qualities of neoprene---does it not give off chemicals as it breaks down over time? If so, what are those? I will check it out, too.


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## earthfrog (May 18, 2008)

Ed said:


> Hi Susan,
> 
> My background is in biochem and the article you provided indicates a toxicity to the ingredient used to make neoprene not the actual neoprene itself. As a polymerized item, the neoprene does not cause those toxicities of the monomer used to make the neoprene.
> 
> ...




As I thought, the risk is in the breakdown of the product, albeit somewhat negligable. In my understanding, this generally occurs more readily with age (correct me if I'm wrong), and so mainly it would be advisable not to allow long-term exposure (such as use neoprene tubing in a viv), although this would not necessarily be a better option than PVC tubing. Although the risk is minimal, it is not nil. I wonder about the effects of handling all of the permeable frog eggs with any type of glove at this point. 


Here is an excerpt from the MSDS sheet:

NEO009 DuPont Performance Elastomers L.L.C. Page 6
Material Safety Data Sheet
(STABILITY AND REACTIVITY - Continued)
Incompatibility with Other Materials
None reasonably foreseeable.

Decomposition
*Hazardous gases or vapors can be released, including carbon
monoxide, hydrogen chloride (HCl), organic acids, aldehydes,
alcohols.*----------------------------------------------------------------------


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## Ed (Sep 19, 2004)

It depends on what you mean by unstable.. degradation products in and of themselves are not necessarily directly harmful.... look at glass.. it is man altered silica sand with one or more additives that is virtually immortal... then there is fired clay (like used in pots or ceramics)... 

I know for a fact that the use of neoprene mesh is a standard in laboratory anuran colonies ranging from Leopard frogs to various Xenopus species and has been included for decades. If it was leaching toxic byproducts then a lot of toxicological studys would have been skewed and it is tested for... 

Neoprene in and of itself is very resistent to a number of items that degrade plactics and rubbers like hydrocarbons.. It will age and breakdown with slow oxidation but it tends to break into smaller particles and not release polymers and even raw formulations are stable when exposed to heat (up to around 200 F for raw untreated formulations). 

Your listing under the MSDS is what happens if you burn it, expose it to a really corrosive material under activations conditions like permagenate under acidic conditions and some heat. It is not its natural breakdown product.



Ed


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## earthfrog (May 18, 2008)

Ed said:


> It depends on what you mean by unstable.. degradation products in and of themselves are not necessarily directly harmful.... look at glass.. it is man altered silica sand with one or more additives that is virtually immortal... then there is fired clay (like used in pots or ceramics)...
> 
> I know for a fact that the use of neoprene mesh is a standard in laboratory anuran colonies ranging from Leopard frogs to various Xenopus species and has been included for decades. If it was leaching toxic byproducts then a lot of toxicological studys would have been skewed and it is tested for...
> 
> ...


Thanks, Ed! It's a real privilege to have such expert info readily available, and really the only way to put two-and-two together in cases such as these. I feel OK about using neoprene gloves in my tank now. Otherwise, I have been washing with scalding water/soap and sterilizing a bit with white vinegar...
So, a rare product---I'm still a skeptic, but I'm a bit relieved...


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## Ed (Sep 19, 2004)

Basic handwashing is sufficient for use between tanks. There is actually a paper out that shows that in the field it is better to use bare hands and wash between specimens when testing for chytrid than to use rubber gloves (latex or vinyl) see Survival of the amphibian chytrid fungus Batrachoc...[Dis Aquat Organ. 2008] - PubMed Result

Ed


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## earthfrog (May 18, 2008)

Ed said:


> Basic handwashing is sufficient for use between tanks. There is actually a paper out that shows that in the field it is better to use bare hands and wash between specimens when testing for chytrid than to use rubber gloves (latex or vinyl) see Survival of the amphibian chytrid fungus Batrachoc...[Dis Aquat Organ. 2008] - PubMed Result
> 
> Ed


Yeah, I do remember reading that as well---I think washing with hot water is a key factor in sanitizing your hands as well b/c chytrid dies above body temps. Thanks again!


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## earthfrog (May 18, 2008)

I found these links on neoprene---if it can cause allergies by exposure to human skin, might there be other subtle effects on frogs?

http://www.crouse-hinds.com/crousehinds/resources/msds/1826190.pdf

Here's another article that shows that polychloroprene degrades when exposed to a ferrous-hydrogen peroxide solution and then polychromatic light, without having been heated to 200 degrees or exposed to caustic materials (known as the Photo-Fenton reaction)---I had to purchase this report to learn this:

ScienceDirect - Polymer Degradation and Stability : Polychloroprene degradation by a Photo-Fenton process

So, it is still an unstable compound, in isolated conditions but perhaps not as toxic as the other options when wearing gloves for working in a frog tank. Although it would be unusual for someone to be sterilizing an established tank with hydrogen peroxide, this might trigger the photodegradation process if there were iron-enriched supplements in the area. I think for the most part I will just be using the bare-hand route as usual.
Any thoughts, Ed? I am undoubtedly making some layman's error...


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## earthfrog (May 18, 2008)

We all know that substances break down---nothing is indestructable. This study shows that, like natural rubber, synthetic rubber such as neoprene (polychloroprene) breaks down over time and can cause degradation just as neoprene can if it has been exposed to caustic materials, although it is much slower by simply aging:

ScienceDirect - Thermochimica Acta : Time–temperature dependence of the thermo-oxidative aging of polychloroprene rubber : : The time–temperature-transformation (TTT) superposition method and the lifetime prediction

So, replace neoprene gloves early if they will be used in long-term care, I think, and take care not to use them with other oxidizing agents such as hydrogen peroxide to protect their integrity. I'm done with the neoprene route now---you can all rest easy.


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## elmoisfive (Dec 31, 2004)

Susan,

As a chemist I can assure you that neoprene is a pretty inert substance under most normal conditions. Even the Photo-Fenton process you reference is not something that I hope you would have going on in your viv.

The allergic sensitivity attributed to neoprene is oftentimes due to other components found with neoprene based adhesives such as rosin, some byproducts of the manufacturing process, etc.

So poor quality neoprene I might be more concerned about but consider your standard film cannister which by the way used to have utility for storing film, not exactly inert to chemical reactions (ahh the good old days pre-digital cameras).

Ed is spot on that what goes into neoprene is far more noxious and the degradation product(s) of neoprene tend to be smaller chunks of neoprene. 

I work in the human health field and we have lots of info on what various plastics are or are not releasing when in contact with fluids or biological systems (called extractable/leachable testing). I'm always intrigued when I see reports that this or that material is dangerous and in truth nothing is absolutely safe. But I find that the scare tactics used to 'zip up' some of these reports are concerning and put the public in the position of trying to sort out conflicting datasets. 

I suppose the best path to take if one has issues is to use only natural materials in the viv but recognize that those natural materials may not be totally safe as well.

Good question though.

Bill


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## earthfrog (May 18, 2008)

Hey, thanks Bill!
I can't say that this particular report was used by anyone engaged in such 'scare tactics' to voluntarily promote its complete disuse, but I found it helpful in that I can find out for myself how much I want to trust something. I don't tend to 'jump' at reports touted by news organizations, especially considering their non-objective stance on things.
I think all froggers should be conscientious and research these things for themselves as well. 
I agree that nothing is safe, even natural things---I treat herbs with the same caution I treat drugs, for instance---but I am indeed far more concerned with plastics than with neoprene. All things break down, yes---human skin, gloves, film canisters---but the conundrum at the root of this is, I think, establishing firm protocol as to the safe use of such compounds in frog-husbandry, and further, circulating that information to the amateur frogger such as myself. 
(I misspoke earlier when referring to 'neoprene' in that I was alluding to 'nitrile' instead, but upon further investigation I am glad to learn that it is more stable than nitrile, vinyl and other compounds.)


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## frogfreak (Mar 4, 2009)

Laura and I prefer to wear neoprene when working in the vivs. How do you know you don't have the flu, cold, or virus? You can have these before showing symtoms.


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## Ed (Sep 19, 2004)

earthfrog said:


> (I misspoke earlier when referring to 'neoprene' in that I was alluding to 'nitrile' instead, but upon further investigation I am glad to learn that it is more stable than nitrile, vinyl and other compounds.)


Just make sure that anything you are using does not have talc on it as that will irritate the skin of the frogs. 

Ed


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## Ed (Sep 19, 2004)

earthfrog said:


> Here's another article that shows that polychloroprene degrades when exposed to a ferrous-hydrogen peroxide solution and then polychromatic light, without having been heated to 200 degrees or exposed to caustic materials (known as the Photo-Fenton reaction)---I had to purchase this report to learn this:


Sorry I had to laugh when I saw this one... how many hobbyists are going to be exposing thier neoprene (or anything else) to a ferrous hydrogen peroxide solution given that one of its main uses is in industrial waste treatment? 

Ed


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## earthfrog (May 18, 2008)

Ed said:


> Sorry I had to laugh when I saw this one... how many hobbyists are going to be exposing thier neoprene (or anything else) to a ferrous hydrogen peroxide solution given that one of its main uses is in industrial waste treatment?
> 
> Ed


[Yeah---a bit of a stretch, I know---but I've never researched any of this before, so I had to get my feelers into different studies. It was fun (especially watching me blunder around, I guess) doing the digging and getting to the bottom of things, though. I have to try and find things out for myself on stuff in addition to other opinions before I can make a judgment. Thanks for your patience, and good spirit, all.] 

Now that I've overdone that neoprene issue----onto plastics and the endocrine disruptor bit...BPA. I have read that the release of BPA occurs through freezing or heating plastic, such as would occur by dishwashing, boiling or putting into your home freezer. Also, it breaks down over time and releases bisphenol-A, which is also a synthetic estrogen. 
Could there also be additional plastic-related chemicals that have a residual trace from the film that used to be in film canisters?


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## earthfrog (May 18, 2008)

Ed said:


> Just make sure that anything you are using does not have talc on it as that will irritate the skin of the frogs.
> 
> Ed


yeah, I did read that was on the neoprene gloves, too---they put it on the inside sometimes to make it easy to put on, right? Or is it only on the outside? I guess it would depend on the brand, and it might be a good idea to wash the gloves before using them.


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## earthfrog (May 18, 2008)

frogfreak said:


> Laura and I prefer to wear neoprene when working in the vivs. How do you know you don't have the flu, cold, or virus? You can have these before showing symtoms.


Nice analogy---good point.


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## elmoisfive (Dec 31, 2004)

frogfreak said:


> Laura and I prefer to wear neoprene when working in the vivs. How do you know you don't have the flu, cold, or virus? You can have these before showing symtoms.


Glenn,

The probability is low that a pathogen you harbor will infect the frogs or visa-versa. Many viruses are highly specialized for the species they infect. On the other hand if you have open cuts, sores etc. on your hands it's a good precaution to keep from getting all the junk from the viv off your skin.

To the point Ed raised earlier the biggest challenge from something like disposable plastic gloves is the other junk that comes with them. By and large they are designed to protect the wearer from the external environment not the other way around. The different chemical composition of the gloves speaks more to the protection given against various factors such as pathogens, chemicals etc.

In fairness though I can think of at least one very successful frogger from the Pacific Northwest who is pretty faithful about using gloves while working in his vivs and given his track record for husbandry/breeding it doesn't appear to be a major issue.

Bill


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## frogfreak (Mar 4, 2009)

elmoisfive said:


> Glenn,
> 
> The probability is low that a pathogen you harbor will infect the frogs or visa-versa. Many viruses are highly specialized for the species they infect. On the other hand if you have open cuts, sores etc. on your hands it's a good precaution to keep from getting all the junk from the viv off your skin.
> 
> ...


Hi Bill

I were a lot of different hats at work. Sometimes working on the road. Mostly in the office and I do a lot of lab work. Chemical formulations for plastics. I used to wear nitrile and have switched to talc free neoprene. I realize that the chances are low to transfer anything from us to the frogs. It just habit from working with chemicals. The convenience to take off a pair of going from one viv to another is much more convenient than hand washing between vivs. At any given time I do have cuts all over my hands as I still like to get dirty. Fixing machinery every chance I get. That's where I started many years ago.


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## frogfreak (Mar 4, 2009)

earthfrog said:


> yeah, I did read that was on the neoprene gloves, too---they put it on the inside sometimes to make it easy to put on, right? Or is it only on the outside? I guess it would depend on the brand, and it might be a good idea to wash the gloves before using them.


I wouldn't use talc at all. It's supposed to be on the inside. In reality it's all over the place. It helps the glove be put on and absorbs a bit of sweat. If you're working on a viv with disposable gloves you will have to have a rag to wipe your hands off so you can get the next pair on. If your hands are sweaty it's almost impossible to get them on.


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## earthfrog (May 18, 2008)

I want to make it clear that no one need be scared by the information we are discussing, but I think it's important to be sure we know the ins and outs of what we are using in our vivarium. That is the purpose of this thread, not simply to use 'scare tactics' to alarm everyone for no reason. That may be the purpose of the mass media, but it is certainly not the purpose here. Hopefully by reading this thread, you will learn the proper precautions to take when using neoprene, plastics, nitrile, vinyl or other items in your vivarium.


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## Ed (Sep 19, 2004)

elmoisfive said:


> In fairness though I can think of at least one very successful frogger from the Pacific Northwest who is pretty faithful about using gloves while working in his vivs and given his track record for husbandry/breeding it doesn't appear to be a major issue.
> 
> Bill


On this point raised by Bill, the toxicity issues raised by gloves with anurans has been pretty specifically linked to the tadpoles. I raised the issue about talc as we have a vet who insists on them and when working with her I make sure to rinse off the gloves after they are on to reduce talc etc and to moisten them before they contact the skin of the frogs. 

Ed


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## frogfreak (Mar 4, 2009)

earthfrog said:


> I want to make it clear that no one need be scared by the information we are discussing, but I think it's important to be sure we know the ins and outs of what we are using in our vivarium. That is the purpose of this thread, not simply to use 'scare tactics' to alarm everyone for no reason. That may be the purpose of the mass media, but it is certainly not the purpose here. Hopefully by reading this thread, you will learn the proper precautions to take when using neoprene, plastics, nitrile, vinyl or other items in your vivarium.


I don't think anyone is taking this as "scare tactics". I'm not. We've already learned that talc free neoprene are probably the best choice of glove, if people choose to wear them.


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## Homer (Feb 15, 2004)

earthfrog said:


> Many of you have heard already that vinyl, such as that used in shower curtains and flexible sports drink bottles, can be toxic to humans. It can be identified as that 'strong plastic smell'. What you are actually smelling is the plastic emitting hazardous compounds.


I'm guessing that you are referring to pthalates used in flexible vinyls as a plasticizer. My understanding is that these are a possible endocrine disruptor, but that studies are not entirely conclusive as to what levels cause deleterious effects in humans. 

I think this is one plastic I might try to stay away from, but I can't think of any flexible vinyl products I use with my frogs. On the other hand, Ken and Barbie dolls are made with vinyl having high amounts of pthalates in them.



earthfrog said:


> We also are aware that even polycarbonate plastic is not entirely safe.


While I agree that nothing is entirely safe, do you have references to support an assertion that polycarbonate is unsafe or dangerous? That would be helpful in discussing whether polycarbonate is unsafe for use in frog tanks. My understanidng is that the main question of safety with polycarbonate is Bisphenol A, but that it is emitted from polycarbonate at about 4000 times less than "the maximum acceptable or "reference" dose for BPA of 0.05 milligrams per kilogram body weight per day established by the U.S. Environmental Protection Agency." Polycarbonate Plastic and Bisphenol A .

Polycarbonate is often sold under the trade name "Lexan" or generically called "bullet proof glass", and has been used for high end fish tanks and aquaria, although it is usually more expensive than the typcial acrylic sheets, and therefore not commonly used. It's probably a non-issue to most froggers just because it isn't typically used, unless you have specific vivaria decorations that you know are polycarbonate. Even then, I would submit that there's not much indication that polycarb would be a negative to frogs.

On second thought, it's possible that some of the petri dishes that I use for egg deposit sites are polycarbonate . . . I'll have to get back to you. Since I have some froglets that developed as eggs in those dishes, and are now breeding, my guess is that it's a non-issue, but I suppose there's always a possible negative side effect. Then again, my non-mercury tooth fillings have a certain amount of bisphenol-a in them, and long term studies indicate that no trace of this is found in the blood after fillings are put in place. ADA.org: Bisphenol A and Dental Materials



earthfrog said:


> Neoprene, a synthetic rubber, is used in creating chemical-resistant gloves, has been shown to mutate tads almost instantly upon contact


I think this was covered above, such that neoprene is not likely to be a problem. I personally don't use neoprene in my frog tanks, though.



earthfrog said:


> I have noticed that film canister also have a 'plastic smell', but they are not made of the same type of plastic.


If I remember correctly, most film canisters have a #2 on the bottom of them, indicating that they are composed of high density polyethylene. My understanding is that these do not contain Bisphenol A, which is probably at the heart of your concern with polycarbonate above. I am not aware of concerns surrounding HDPE, as I think these are generally considered safe. Please feel free to correct me here. 

I have also used film canisters in frog tanks for about 8 years without any noticeable negative effects. Other froggers have used these longer than that for tadpole deposit sites, etc. While this does not necessarily mean that there are no negative effects, it does make me feel better about my continued use of film canisters, as long as I can still get them (the digital camera age will eventually eliminate these as a viable source for egg deposit sites).



earthfrog said:


> Further studies suggest that plastics and other related products are not all that wholesome.


The term "plastics" covers a broad range of different products with vastly varying components. It's a little like trying to say that tuna is not all that wholesome because it contains high levels of mercury, therefore studies suggest that fish and seafood are not all that wholesome. (I'm not sure what you mean by using the term "wholesome") There are certainly plastics that one might be wary about, but it might be more useful to first identify the most common types of plastics that we would use with our frogs, then identify whether those plastics have potentially harmful results when used along with our frogs. 



earthfrog said:


> Can anyone shed some light on this subject in lieu of the long-term of our frogs? We can all benefit from what you have to offer---give your opinions supported by studies where possible. Please cast your vote and make your voice heard as well.


I can't really cast a vote, as there are so many different types of plastics. However, my guess is that most of the plastics that we use in frog tanks and in frog keeping are relatively innocuous for the long term health of the frogs, but I'd be happy to see studies that indicated otherwise.


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## earthfrog (May 18, 2008)

Thanks everyone. All of you have given very informative answers, and I thank you---your knowledge in this avenue certainly encompasses my own. I am always amazed at the careful consideration that froggers give to matters like these, and it is encouraging to this still novice frogger.


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## Ed (Sep 19, 2004)

Homer said:


> While I agree that nothing is entirely safe, do you have references to support an assertion that polycarbonate is unsafe or dangerous? That would be helpful in discussing whether polycarbonate is unsafe for use in frog tanks. My understanidng is that the main question of safety with polycarbonate is Bisphenol A, but that it is emitted from polycarbonate at about 4000 times less than "the maximum acceptable or "reference" dose for BPA of 0.05 milligrams per kilogram body weight per day established by the U.S. Environmental Protection Agency." Polycarbonate Plastic and Bisphenol A .
> 
> Polycarbonate is often sold under the trade name "Lexan" or generically called "bullet proof glass", and has been used for high end fish tanks and aquaria, although it is usually more expensive than the typcial acrylic sheets, and therefore not commonly used. It's probably a non-issue to most froggers just because it isn't typically used, unless you have specific vivaria decorations that you know are polycarbonate. Even then, I would submit that there's not much indication that polycarb would be a negative to frogs.
> 
> ...



Hi Homer,

Bisphenol A and frogs is a problem in levels designated safe by the goverment. For a couple of examples I refer you to the following two as a sample... 

Heimeier, R, B Das, DR Buchholz and YB Shi. 2009. The xenoestrogen bisphenol A inhibits postembryonic vertebrate development by antagonizing gene regulation by thyroid hormone. 

ScienceDirect - Environmental Research : Bisphenol A induces feminization in Xenopus laevis tadpoles*1

It must be noted that the release of bisphenol A from polycarbonate can be significantly modified by exposure to heat and/or acidic conditions. These conditions increase the rate of degredation and release of the bisphenol A into the localized enviroment. 

Ed


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## earthfrog (May 18, 2008)

Ed said:


> Hi Homer,
> 
> Bisphenol A and frogs is a problem in levels designated safe by the goverment. For a couple of examples I refer you to the following two as a sample...
> 
> ...


I thought that could happen with tads as well as with fish---as I understand it they also have sex-change abnormalities as a result of BPA contact. From what I understand about thumbnails, a few years ago they seemed heavy to males...but now it's hard to find males. I called around and asked vendors, and they were saying everyone was asking for males. Makes you wonder if there is some low-level effect going on there.


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## Homer (Feb 15, 2004)

Ed said:


> Hi Homer,
> 
> Bisphenol A and frogs is a problem in levels designated safe by the goverment. For a couple of examples I refer you to the following two as a sample...


Thanks, Ed. I cannot get to the actual results in the article, as only the abstract is published. Any idea as to whether the concentrations are within the general b-a levels secreted by polycarbs under near room conditions and the not-overly acidic conditions that we see in frog-friendly environments?



Earthfrog said:


> From what I understand about thumbnails, a few years ago they seemed heavy to males...but now it's hard to find males. I called around and asked vendors, and they were saying everyone was asking for males. Makes you wonder if there is some low-level effect going on there.


I doubt any sex ratio skewing is occuring due to exposure to polycarbonates, unless you can point to a standard polycarbonate piece that we all use in rearing thumbnails. While petri dishes might possibly be polycarb, as pointed out above, film canisters are not (and these are what I believe most use for collecting eggs in egg feeders, if any plastic piece at all is used).

I still think that rather than discussing in general what "plastics" are dangerous, it would be more constructive to look at which plastics we use in standard frog husbandry, then consider whether those particular plastics are dangerous. Otherwise, we have so broadly defined the area of concern in this inquiry--i.e. "plastics"--that we cause concern where one should not be.

If we want to talk in generalities about the most likely carrier for endocrine disruptors that can have deleterious effects in almost immesurable quantities, we should be far more concerned about the water that we use rather than the fixtures in our set-ups. Considering that I know several in the hobby swear by and use "spring water", this would be far more of a concern to me.

At the end of the day, I guess my comments to this thread come down to the practical consideration that the only two plastic components that I use in my frog tanks (which are almost all glass tanks) are petri dishes and film canisters. Since (1) I do not see any assertion that HDPE is a likely endocrine disruptor or other danger to frogs, and (2) I know of several froggers that have used the plastic petri dishes for over a decade with no apparent problems, I have no real concern.


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## Ed (Sep 19, 2004)

Hi Homer,

This article has the right references even though its not up the standard I would normally post 

http://www.tecniplast.it/_assets/panorama/03-04 winter.pdf

Ed


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## james67 (Jun 28, 2008)

ok being an industrial design student i thought i would get out the old GE plastics book and list commonly used plastics (commonly for products not necessarily frogs)

here goes
ABS 
PC/ABS
ASA
PC
modified PPO
PEI

when trying to determine which plastic you have simply look at the little recycle symbol, it will have a number in the middle..
1=PET (Polyethylene Terephthalate)
2=HDPE (High Density Polyethylene)
3=PVC (Polyvinyl Chloride)
4=LDPE (Low Density Polyethylene)
5=PP (Polypropylene) 
6=other (usually a combination of different plastics)

there are 2 types of plastic, thermoset, and thermoplastic. the ones you are likley to encounter in viv building are thermoplastic, so you can narrow it down

james


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## Dragonfly (Dec 5, 2007)

My education limits my easily following all the scientic discussion, although I find it beneficial to read and read again. Then follow up what I read with what I do know of scientic method.

So other than an aestheic response I will not weigh in on plastics. 

And where can I reliable get glass petri dishes - There are some good things I can do with the plastic ones, but would love to get some good glass ones.

However I will weigh in on talc. In my humble opinion knowing how it is carcenigenic for women and thus taken out of "higher" end baby powder here in the States - now mostly cornstarch, I think we should all just stay away from talc. 

As to the natural vs man-made argument, Susan, I am glad you pay attention to the dangers of the herbal, etc. I recall earlier in the move to more natural "medicine" people touting willow bark as the safe natural alternative to aspirin. With the chemical similarities, the complications to persons with medically significant contraindications to the use of salicylates were rather major as willow bark is essentially a salicylate.

And even within species, there are some significant differences in what is or is not harmful. For example, I know the effects of a common beer on me or any ETOH are rather seriously negative.


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## james67 (Jun 28, 2008)

Dragonfly said:


> And where can I reliable get glass petri dishes - There are some good things I can do with the plastic ones, but would love to get some good glass ones.


try amazon.

they have good cheap boro-glass (ive had mixed results with shipping as some pyrex is rather thin)

Amazon.com: Glass Petri Dishes: Toys & Games

james


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## earthfrog (May 18, 2008)

Ed said:


> Hi Homer,
> 
> This article has the right references even though its not up the standard I would normally post
> 
> ...


So, based on that article and the consequent release of BPA from HDPE with high temps, would you assert that it may not be a good idea to 'superheat' HDPE to sterilize or clean it, but rather just use room-temp, sterile water and dish soap to clean instead?

Also, could there be residual chemicals from the film canisters/HDPE that need to be cleaned off prior to the first use? (I can smell a difference before and after washing with natural dish soap and water, that's why I'm asking.)


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## Homer (Feb 15, 2004)

earthfrog said:


> So, based on that article and the consequent release of BPA from HDPE with high temps, would you assert that it may not be a good idea to 'superheat' HDPE to sterilize or clean it, but rather just use room-temp, sterile water and dish soap to clean instead?
> 
> Also, could there be residual chemicals from the film canisters/HDPE that need to be cleaned off prior to the first use? (I can smell a difference before and after washing with natural dish soap and water, that's why I'm asking.)


Where are you seeing that BPA is being released from HDPE? My reading of the article indicates that polycarbonates are being compared to polysulfones and polyerithimides. Further, the article goes on to say that new polycarbonates can release up to about 300 parts per billion when they have been heat sterilized (polycarbs have a melting point above 250 C, where sterilizing temp is usually at about 130 C--well above the boiling point of water). I still have not seen the actual numbers that indicate where the endocrine disrupting effects begin in amphibians, as the cited references require a membership to a database to see the full results.

Regardless, the plastics in the cited article are not the same as high density polyethylenes (HDPE), which are usually touted as a safer plastic alternative to those who are concerned about polycarbonates leaching BPA. 

This is where I see this thread being a potential cause of paranoia--there is an assumption in the beginning post that all plastics are inherently unsafe for frog use, and that all plastics contain BPA, which is simply not the case. This follow-up post continues to muddy the water by mixing up HDPE with polycarbonate. As such, I think this is a confusing thread for any beginners that may be trying to figure out what they can or cannot use in their frog tanks, as there are incorrect assumptions beginning in the first post.

Regardless, answering the question above, I personally would agree that you do NOT want to superheat or sterilize HDPE with heat, mostly because it has a melting temperature right around the temperature that is required to sterilize (about 130 degrees C), and you'll end up with a pile of plastic goo instead of a film canister if you heat sterilize the containers. 

I personally just wash my film canisters with hot soapy water, rinse well, and use one set of film canisters for one particular tank--then you have no worries about cross-contamination. Film canisters are inexpensive enough now that if you're concerned about contamination you can simply recycle any that you might considered contaminated.


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## Homer (Feb 15, 2004)

In the interest of full disclosure, and as a counterpoint to my post above, I should note that I personally try to avoid drinking out of polycarb containers, don't use any polycarb tanks, and generally try to stay away from polycarb in my frog tanks for two reasons: (1) it's expensive, and (2) I agree that there is no reason to expose myself or frogs to an estrogen mimic like BPA. I'd probably feel the same way about using soft vinyl tank decorations, but I haven't seen the need to use any such decorations.

The plastics that I do use in my tanks are polypropylene tubing for water features, abs components in some of my tanks where there is a water feature, acrylic petri dishes, and HDPE film canisters. Am I concerned about their effects on frogs? Not so much, as I haven't seen a detrimental effect on the frogs. In fact, the use of film canisters in the thumbnail tanks allows me to pull tads and raise them myself, which leads to bigger froglets at morphing and lower mortality.

Maybe that's the answer I should have given first. The rest, in my book is just hashing out details that really don't have a place in my brand of husbandry, more out of practicality than any other reason.


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## earthfrog (May 18, 2008)

Hi Homer,

Thanks for the advice. I found this---it's a good layman's site for a general guide to plastic safety, and we are focusing more on PC and HDPE than the other plastics, here:

Step 5: Be wise with plastics | The 5 Easy Steps | Healthy Child Healthy World

It mentions not microwaving plastic, so those of you with FF containers, nuke the cultures in glass, not plastic.


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## earthfrog (May 18, 2008)

Hi Homer, Ed, James and all who have given their good advice thus far, 

I created this thread with the understanding that educated persons would be giving their opinion. Obviously, the thread title reveals some ignorance on my part, but if I was knowledgeable in the first place, why then would I be asking the questions? (I was also the one in class that everyone made fun of for asking questions...)
I thank you for your patience and generous advice. I have a great deal of respect for those of you who have taken the time to answer on this thread, and I now have a more positive outlook on plastics, in that I see what good conclusions we have established (or re-established) so far:

*Neoprene is safe to use as long as it is not very old
*Vinyl, talc and nitrile are questionable for use in frog husbandry
*Polycarbonate (PC) and polyethylene (PE) are 'safer' plastics to use w/frogs
*It's important to explore your options and to become educated.
*Don't microwave plastics as they may decompose faster.

Feel free to add to or edit this list so that every reader need not sort through all of our discussions to reach a conclusion.


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## Homer (Feb 15, 2004)

earthfrog said:


> Hi Homer, Ed, James and all who have given their good advice thus far,
> 
> I created this thread with the understanding that educated persons would be giving their opinion. Obviously, the thread title reveals some ignorance on my part, but if I was knowledgeable in the first place, why then would I be asking the questions? (I was also the one in class that everyone made fun of for asking questions...)
> I thank you for your patience and generous advice. I have a great deal of respect for those of you who have taken the time to answer on this thread, and I now have a more positive outlook on plastics, in that I see what good conclusions we have established (or re-established) so far:
> ...


I would amend the conclusions as noted:

*Neoprene is safe to use as long as it is not very old
*Vinyl, talc and nitrile are questionable for use in frog husbandry--*Where did we ding nitrile*?
*Polycarbonate (PC) and polyethylene (PE) are 'safer' plastics to use w/frogs--*Polycarbonate is one that we noted has BPA, which MAY (or may not) have deleterious effects. I have seen no issues listed with Polyethylene.*
*It's important to explore your options and to become educated.*Agreed*
*Don't microwave plastics as they may decompose faster.*I still don't see the problem with nuking your fly cultures*

If we all learn something, or question something we thought we knew (I've now got a question about BPA concentrations in polycarbs), I consider it a decent thread. Thanks, Susan. It's just very easy for a thread like this to become a confusing string for any newbies that may be searching for something like "is plastic safe for frogs", and I would hate for that to be a basis for someone to decide that the hobby is just too complicated or confusing and decide to keep leopard geckos instead.


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## Ed (Sep 19, 2004)

Hi Homer,

Check out the effective levels of effect in this article ScienceDirect - General and Comparative Endocrinology : Developmental and triiodothyronine-induced expression of genes encoding preprotemporins in the skin of Tago’s brown frog Rana tagoi

snip "Exposure of the animals to 10−8 M T3 and 10−6 M bisphenol A, an endocrine disrupting chemical that potently inhibits the action of thyroid hormones (THs), reduced expression of the preprotemporin-1TGb gene by 10-fold and the preprotemporin-1TGa gene by threefold. We propose that T3-stimulated synthesis of antimicrobial peptides is important in protecting the animal against microorganisms, particularly at metamorphosis and during skin moulting, but environmental pollutants can inhibit peptide synthesis and render the animal susceptible to invasion by pathogens."endsnip

BPA has multiple potential effects in anurans.. and some can be very subtle particuarly when dealing with the microexposure effects. 

Ed


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## Ed (Sep 19, 2004)

The standard insect culture containers typically used for fruit flies are autoclavable with no problems and as such should not have a problem with the microwave. 

They are sold as autoclavable by the biosupply companies... 

Ed


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## Ed (Sep 19, 2004)

Nitrile is listed as causing tadpole death here (full article) http://www.parcplace.org/Cashins_etal_2008_glovesandtads .pdf


HDPE (high density polyethylenes are safe as they do not contain pthalates as softeners). 

Ed


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## earthfrog (May 18, 2008)

*Plastic analysis outcome*

Updated summary outcome of this thread (Edit as needed):

*Neoprene is safe to use as long as it is not very old and has begun to decompose.
*Vinyl, talc (sometimes present on neoprene--buy talc-free neoprene gloves) and nitrile are not very safe for use in frog husbandry
**High-density Polyethylene (HDPE) and Polypropylene (PP) are two of the the 'safest' plastics to use w/frogs.* 
*Boiling/freezing HDPE, PC or other less stable plastic containing BPA can greatly accelerate the release of BPA, which has multiple harmful effects on frogs.
*It's important to explore your options and to become educated.


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## Homer (Feb 15, 2004)

Ed said:


> Hi Homer,
> 
> Check out the effective levels of effect in this article . . .
> snip "Exposure of the animals to 10−8 M T3 and 10−6 M bisphenol A, . . . endsnip
> ...


That's the type of info I was looking for! Okay, now let's put it in perspective to see if we have a likely problem (I'm doing the math while I type, so bear with me). The exposure to BPA that resulted in deleterious effects in the experiment was 1x10 to the -6 Molar BPA. According to the article you cited earlier, regular ole' polycarbonate when heat sterilized can release about 300 parts per billion BPA, which was not enough to make a statistical difference in rats; but we're talking about anurians, which we all know to be the canaries in the coal mine when it comes to endocrine disruptors. Oh, joy, the fun of converting . . . brings me back to Chem I.

Molarity is moles per liter of total solution. BPA has a mass of 228 g/mol. So, a 1 x 10-6 M solution would be 228 grams of BPA in one million liters of solution. Let's assume the total solution is water (yes, not technically correct, but close enough to get us in the ball park) in converting Molarity to compare to the parts per billion reference. Water has a mass of about 18 g/mol, so we're looking at 228 grams of BPA per 18,000,000 grams of solution (approximately). That's a concentration of about 1.3 x 10-5 that was found to be deleterious. Compared to the 300 parts per billion BPA that is the high end of what normal polycarbonate exudes after sterilization, which is 300 grams BPA per 1 x 10-9 grams solution = 3 x 10-7.

It looks to me like normal polycarbonate exposure would still be a few hundred times less BPA than what has been found to be deleterious, unless my math is off. That's not exactly what I would call no worries, but it is quite significantly lower.


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## Homer (Feb 15, 2004)

*Re: Plastic analysis outcome*



earthfrog said:


> Updated summary outcome of this thread (Edit as needed):
> 
> *Boiling/freezing HDPE, PC or other less stable plastic containing BPA can greatly accelerate the release of BPA, which has multiple harmful effects on frogs.


No. Remember, HDPE does not contain BPA. You can melt it, freeze it, turn it into a plasma, or eat it for dinner, but it won't release BPA. Polycarbonate (PC) contains BPA.


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## Homer (Feb 15, 2004)

Ed said:


> Nitrile is listed as causing tadpole death here (full article) http://www.parcplace.org/Cashins_etal_2008_glovesandtads .pdf
> 
> 
> HDPE (high density polyethylenes are safe as they do not contain pthalates as softeners).
> ...


It looks to me like it isn't necessarily nitrile per se that is deadly, but some of the chemical residues that may be found on nitrile gloves, unless I am reading it wrong. They went on to test vinyl gloves and found them toxic as well unless they were washed first.


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## Ed (Sep 19, 2004)

Let me work my way through this from a different angle.. 

300 ppb is the equivalent to 300 micrograms per liter (1000 grams of water at STP is by definition of one liter) and a microgram is 10-6 grams 

so 300 micrograms/liter x 1 gram/1000 micrograms x 1 mol/228 grams BPA = 0.0013 mol BPA/liter which is a significantly higher concentration than the reported doses of 10-6 to 10-8. 

I think that is correct but it has been a long time since I had to convert anything by hand... 

Ed


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## Ed (Sep 19, 2004)

Homer said:


> It looks to me like it isn't necessarily nitrile per se that is deadly, but some of the chemical residues that may be found on nitrile gloves, unless I am reading it wrong. They went on to test vinyl gloves and found them toxic as well unless they were washed first.


Hi Howard,

There isn't any mention of the toxicity of washed nitrile gloves in the paper so that is an assumption that they are safe.. 

It was only washed vinyl gloves that are safer (but if I remember correctly, one species still showed toxicity issues with the washed gloves). 

Ed


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## earthfrog (May 18, 2008)

Homer said:


> It looks to me like it isn't necessarily nitrile per se that is deadly, but some of the chemical residues that may be found on nitrile gloves, unless I am reading it wrong. They went on to test vinyl gloves and found them toxic as well unless they were washed first.


Can there be chemical residues on otherwise 'harmless' plastics from the mfg. process that should be cleaned before use, such as on the HDPE film canisters?


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## earthfrog (May 18, 2008)

Updated summary outcome of this thread (Edit as needed):

*Neoprene is safe to use as long as it is not very old and has begun to decompose.
*Vinyl, talc (sometimes present on neoprene--buy talc-free neoprene gloves) and nitrile are not very safe for use in frog husbandry
*High-density Polyethylene (HDPE) and Polypropylene (PP) are two of the the 'safest' plastics to use w/frogs. 
*Boiling/freezing Polycarbonate (PC) or other less stable plastic containing BPA can greatly accelerate the release of BPA, which has multiple harmful effects on frogs.
*It's important to explore your options and to become educated.


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