"Some common substances are lethal at levels of parts per
 billion, such as"

Peter,

You did not give units!  Without units your post is meaningless.

For example you give the LD50 for ethanol as 918 grams.  LD50s are often expressed as weight per Kg of test animal.  Surely you are not saying ethanol has an LD 50 of 918 grams/kg.  I am guessing you mean 918 grams per average sized human as sometimes LD50s are expressed this way also?  But, even this does not seem right.  That would mean a lethal dose was 27 ounces of pure ethanol or about two liters of whiskey.  That is about two to three times less toxic than water depending on the size of that human.  I think ethanol is more toxic than that.  Even comparing the numbers you gave does not help me.  Your toxicity for table salt is 218 grams, about three times less toxic than alcohol.  That salt toxicity does seem about right to me for an average human but you list glyphosate as being 340 grams and my memory is glyphosate is roughly three times as toxic as table salt.  Or is it 1/3 that of table salt?  Memories can fail, particularly mine.

Dick

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html