This is a link and the text of a research article that accurately states the LD 50 of whole apricot seeds. Basically the LD 50 is 3.3g/kg by oral ingestion; http://www.home.zonnet.nl/galien8/amygdalin/amygdalin.html
Welcome to the Straight Dope Message Board, acu_j!
It’s customary here to provide a link to the article under discussion. I presume you were reading and responding to Cecil’s article Are apricot seeds poisonous? Not a big deal, since you didn’t know.
Thanks for the added information, by the way. 
However, in the article linked, I do not see where the specific mention of an LD-50 for Apricot seeds is made. 