# Thymol vs formic and oxalic acids



## Michael Bush (Aug 2, 2002)

Formic acid is the acid in an ant bite that makes it burn and the trail they leave everywhere. Thymol is that nasty taste in Listerine. Oxalic acid is the bite you taste in your rubarb pie.

Which do you want in your honey?


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## JohnBeeMan (Feb 24, 2004)

> Which do you want in your honey?

This supposes that the ppm (parts per million) of thymol in a mouthful of Listerine is the same ppm as a spoon full of honey.

Maybe a better way to ask the question would be:

Of oxalic acid, formic acid and thymol, which is the most toxic at same levels of concentration (ppm)?


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## Michael Bush (Aug 2, 2002)

Thymol is essential oils from the Thyme plant. Obviously in amounts large enough to taste them (listerine and food with Thyme as a apice) it's not toxic.

Oxalic acid is in many foods including rhubarb and honey. Oviously in amounts large enough to give these foods some bite (you can taste it) it's not too toxic, although there is some discussion about Oxalic acid as the cause of kidney stones, which are made of calcium oxalate.

I don't know what amounts of formic acid are in foods, but I have heard that there is some in some foods.

As for the issue of toxicity I think the information that would be useful would be this:

Toxicity levels (defined as levels at which there are measurable detrimental effects) (in PPM or other measurements) and mortality levels (defined as levels taht cause death) for:

Humans
Bees
Tracheal Mites
Varroa Mites

for each of the following:

Thymol
Oxalic acid
Formic acid
Apistan
Checkmite


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## BeeMiner (Aug 8, 2003)

>Toxicity levels (defined as levels at which there are measurable detrimental effects) (in PPM or other measurements) and mortality levels (defined as levels taht cause death) for:

This is sort of what I was looking for. I'm most concerned with what is harmful at the levels used for treatment and what might stay residually in the wax and/or honey.

The best source I found so far is the Swiss Bee Research Centre http://www.apis.admin.ch/index_e.htm 

Mark


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## Oxankle (Jan 8, 2004)

Let's back up a bit. 

First, Dr. R. has stated repeatedly that his method of treatment with FGMO leaves no detectable traces of either FGMO or thymol in wax or honey. 

Next, I do not believe that the amounts in honey or wax is what is under consideration here. The question would be "How much and how harmful would be the amount of either FGMO, oxalic acid or formic acid that one is likely to be exposed to while treating bees?"

FGMO would be fairly innocuous, dangerous only if one inhaled the oil, a lot of it.


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## BeeMiner (Aug 8, 2003)

Sorry. I knew the results of Dr. R's tests and should have stated that in my initial post about residual amounts. I just lumped the Thymol in with the Oxalic and Formic acids. I don't know much about those two, just what I've read on the Swiss site and some postings on Beesource.

Mark


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## Dr. Pedro Rodriguez (Feb 5, 2002)

Hello folks.
Spring has finally arrived in the plains of Spain! Brrr, it has been rough for our little honey bees!
Re: toxicity of treatments.
Thanks OX!
Thanks Mark for rectifying.
Goes to show what may happen if we "lump" topics. Generalization may obscure what has been carefully planned and executed. 
I agree that further testing of the benefits of FGMO and thymol are still necessary (and still ongoing) but as of now, FGMO and thymol are proving to be effective alternative valuable treatments.
We need to be really concerned with the effects to honey bees and the environment in general, what commercial products, such as "Poncho" or "Gaucho," may do.
Food for thought.
Best regards and God bless.
Dr Rodriguez


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## BeeMiner (Aug 8, 2003)

Well, I'd never heard of Poncho or Gaucho so naturally I did a Google search. One of the sites I visited had this list of pesticides. Check it out, it gave me the "willies" just reading it.
http://www.alanwood.net/pesticides/class_insecticides.html#nitroguanidine_insecticides 


Mark


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## Branman (Aug 20, 2003)

Doing google searches of 'LD50 Oxalic Acid' & 'LD50 Thymol', I find

Thymol - I keep finding LD50 for rats(oral) of 980 mg/kg but another site lists it as 5628 mg/kg

Oxalic Acid - I find 7500 mg/kg a few times for LD50 for rats(oral)...although I did find a site that listed it as 475 mg/kg

Can anyone back up with some more info? I would have thought this would be an easier search...I keep finding conflicting information

[This message has been edited by Branman (edited June 06, 2004).]


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## Michael Bush (Aug 2, 2002)

I bought a book on poisonous plants and was surprised to find almost every plant was also the ones in my edible plant books.

Seems like Oxalic acid, or Tannic acid or some of the other organic acids are the reason they are listed as poisonous. But it is all a question of amounts. In the early spring when these plants come up they are quite good. Later in the year when the acids build up in the leaves they are bitter and dangerous.


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## Dr. Pedro Rodriguez (Feb 5, 2002)

Hello folks.
Nice to see minds at work. Also nice to see your concerns about toxity for the substances that we use for treatment against honey bee parasites. Wonderful
Now lets talk a little bit about your findings in your search and analyze them a little. I will discuss only thymol since this is the only substance with which I have worked in my research. 
You cite the LD50 of 950 mg/Kg for rats. 
950 mgs is just under one gram. That is the amount of thymol, that if administered by mouth to 2 1/2 pound rats would kill 50 percent of the population of rats. Good and fine. No trouble so far, except that this would never happen in real life.
Now to consider honey bees and man where thymol is being used in real life. I have been extremenly careful not to use more than 50 mgs thymol per liter of FGMO. Those of you who use FGMO foggers know how long will take to use up a liter of FGMO for fogging,
a very long time even if you don´t follow instructions correctly. We also know that should we get a whif of the fog, per chance, it is just that, a whif. An infinitesimal amount of thymol in that whif. 
Accredited laboratories have certified that there were no residues of thymol in either wax or honey taken from hives that have been treated with thymol for three consecutive years previous to testing. Zilch, nothing, nada, nix, cero, zero residues. 
Let us take this dissertation a little further. If it takes (nearly) one gram of thymol fed orally to 2 1/2 pound rats, how many grams of thymol would it take for the LD50 for an average man, plus or minus 150 pounds? Given the circunstances, I do not think that this would ever happen. Hence, I think that we should not be concerned about LD50´for thymol. 
How about being concerned about LD 50´s for other pesticides being used regularly for the same illness of honey bees, such as SUPONA, AMITRAZ, etc. I should think so, but I have yet to see postings on LD 50´s for these substances on this forum. 
Do your searches and your math on them, please, and let us know your results.
Best regards and God bless. 
Dr. Rodriguez


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## Oxankle (Jan 8, 2004)

I think we are missing some of the important stuff here.

The concentration of any of the acaricides in honey or wax is going to be small and likely of no importance to us. What is important is the dose we get when applying the stuff. 

I agree with Dr. R; the thymol is going to be in a very low concentration when we get a whiff of it. Most of the time we will not get even a sniff, but when we do it is of no moment. Of course the continued inhalation of oil fogs, with or without thymol, is unhealthy and will lead to lung problems. Work from the upwind end of your rows. 

However, consider oxalic acid. We are dealing with the raw product; we spoon oxalic acid crystals into a pipe and vaporize them. The fumes are enough to bleach wood, leaving deposits on the frames where it is introduced into the hive. The material itself is very corrosive and the fumes can be deadly if inhaled in any quantity. In terms of hazard, a great increase over Thymol. 

I know nothing of formic acid or the method of use, but I would bet that it is similarly more hazardous to use than thymol.
Ox


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## Branman (Aug 20, 2003)

No disrespect, I'm just trying to do research and find out toxicity levels and stuff. I'm not advocating against using thymol/oxalic acid or for using it. But, how are you qualifying your statements? The LD50 levels seem similar to me. Concentrated thymol or oxalic acid is toxic. And while you are delivering a more pure form in the oxalic acid and you are diluting thymol in oil, you are delivering more material with the fogger. The oxalic acid is basically being diluted by air. And if you use Apilife Var, you are using a concentrated thymol product. Once again, data seems to show no traces of either, so again I'm not advocating for or against either. I'm just saying people assume since its 'thymol' from the 'thyme' plant, that it's somehow safer than 'oxalic acid' that happens to be present in rhubarb, spinach, tea, beets, parsley & sorrel because it has 'acid' in it. Are folic acid or citric acid bad for you? Nicotene is a plant product, but I'm certainly don't think its safer than either of these two products.

[This message has been edited by Branman (edited June 06, 2004).]


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## Dr. Pedro Rodriguez (Feb 5, 2002)

Hello folks.
I never thought that there was disrespect intended. I saw an inquiring mind. 
Once again, I commend your intentions in wanting to know. But one thing is wanting to know and another is interpolating findings.
It is like the old saying of mixing apples and oranges. The end result is not the same. 
Those LD 50´s that were reported for rats are extremely high, nearly one gram of pure thymol given by mouth to a hypothetical 2 1/2 pound rat. It is impossible to equate that LD50 to a full grown beekeeper, especially when we are talking about an occassional whif of the stuff if the wind happens to turn on you. 
Like I say, I appreciate your concerns, but you are being unduly quizzical about stated standards. And, definitely, I can not speak for the other brand name that is mentioned. I am sure that the originating laboratories have worked out their standards. It would be interesting if you were to request LD50 studies from them.
Best regards and God bless.
Dr. Rodriguez


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## Branman (Aug 20, 2003)

Agreed. I don't believe either present a hazard in practical, safe use. Commenting on the topic, I just don't think that oxalic, formic or thymol are necessarily more hazardous than another or the delivery mechanisms. At least what little data I've found doesn't support it. I was just commenting on how others are relying more on intuition rather than fact. I *want* to see more information. I *want* to be proven wrong or right. I just don't like the limbo







Once again, thanks for all you've done for the beekeeping community, Dr. Rodriguez

-B

ps. the 'how do you qualify your statement' was not referring to you, Dr R.

[This message has been edited by Branman (edited June 06, 2004).]


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## chemistbert (Mar 4, 2004)

Everyone should read the MSDS (Material Safty Data Sheet) on the product they are using. It is requied by law that the manufacture be able to produce on for you on request. Do a web search and you can generally find one. Really it comes down to don't eat it, breath it, or bathe in it and you'll be fine.


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