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Subject: Re: Oxalic Acid Evaporation
From: allen
Reply-To: Informed Discussion of Beekeeping Issues and Bee Biology
Date: Fri, 12 Mar 2010 08:48:33 -0700

> This will be a very useful URL:
> http://www.agroscope.admin.ch/imkerei/00316/00329/02081/index.html?lang=en
> From the Swiss institute for bee research in Liebefeld.

Thanks for that. It seems to confirm that the risks are minimal.

Here is an excerpt from a URL on that page.  The entire article is worth reading.

Evaporation of oxalic acid - a safe method for the user?
T. Gumpp, K.Drysch, M. Radjaipour, P. C. Dartsch (2003)
Last modification: 02.02.2006 | Size: 330 kb | Type: PDF


Result: All measurements clearly underneath exposure-limit

Evaluation of data led to a clear result: None of the 20 participating
beekeepers reached even half the exposure-limit of 1.0 mg/rn3. (tab. 1). The
average value of the 10 measurements on evaporation procedure was 0.23
mg/rn3, the average value of the 10 measurements on spraying procedure was
0.22 mg/rn3. There was no significant difference between both methods (fig.

To better comprehend these results we must briefly concern ourselves with
the definition of the exposure- limit (MAK-Wert): The exposure-limit is in
such a way selected that for an employee no health damage is to be expected
if he stays 8 hours a day during a working life time at working places at
which the alr concentration of the respective hazardous substance doesn't
exceed the exposure-limit [4].

Thus, based upon the presented data, a commercial apiarist could use oxalic
acid treatments during the whole year 40 hours a week without damaging his

Meaning of the results to apiarist's practice With evaporation- and
spraying-procedure of oxalic acid, beekeepers have possibilities of
treatment against varroatosis whose effectiveness and bee compatibility have
already convincingly been proven [11]. However, there were concerns that in
particular the evaporation procedure was injurious to user's health.

Overcautious scientists therefore warned about evaporating oxalic acid or
recommended preventive measures which made the procedure unpractical, e.g.
wearing ABC protection equipment. The presented study dispelled reservations
against both procedures concerning possible health risks, appropriate
application presupposed.


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