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Informed Discussion of Beekeeping Issues and Bee Biology

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Subject:
From:
Richard Cryberg <[log in to unmask]>
Reply To:
Informed Discussion of Beekeeping Issues and Bee Biology <[log in to unmask]>
Date:
Sat, 7 Dec 2013 07:33:43 -0800
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"doesn't LD50 on a pesticide label refer to the
 dosage which will kill 50% of the humans exposed to that
 dosage?"

A pesticide sold in the US must comply with USEPA requirements including what is on the label.  Here is what EPA says about LD50s on labels:

http://www.epa.gov/oecaagct/ag101/pestlethal.html

LD50s vary greatly at times from species to species, thus there is no one correct LD50.  Generally the two mammals tested for LD50 are rats and mice.  Sometimes rabbits.  It is not at all unusual to see a 10X difference between rats and mice.  Sometimes more, sometimes less.  If the test substance induces barfing it will often test more toxic in rats as rats do not barf.  LD50s in a given species also can vary greatly as to route of entry.  Skin versus inhalation versus oral versus IV.  Thus. the signal words are more meaningful than any absolute value as LD 50 in humans is never known. 

Dick

" Any discovery made by the human mind can be explained in its essentials to the curious learner."  Professor Benjamin Schumacher talking about teaching quantum mechanics to non scientists.   "For every complex problem there is a solution which is simple, neat and wrong."  H. L. Mencken



 

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