Dioxin in Clay

[DrBillC@aol.com]

  Thought you all would like an update on the dioxin in clay fed to chickens.
   EPA gave a presentation at Dioxin '97 and reported the following.
  
  Ball clay (not bentonite) used as an anticaking agent in chicken feed was
  found to have about 1 ppb (yes) TEQ.  This is as dioxins, no furans present,
  and mostly TCDD.
  
  Curious thing, though.  That's the way it comes from the mine.  There are no
  other anthropogenic chlorinated materials (like pesticide residues or
  solvents) present.  It is in three "lenses" (layers) of the clay and
  interstitial layers.  This clay formation was formed in the Eocene era, and
  is like a "mud flat" that extended across a good area of the  western part of
  the eastern US.  There is more than one mine, and in at least one case it's
  found about 90 feet below the surface. 
  
  The enforcement section spent a month on this and found nothing untoward.  To
  keep this short, I won't bore you with more detail, but they can't find the
  hand of man on this anywhere yet, despite looking for it, particularly in the
  form of "midnight dumping".
  
  The rest of the scientists here had no additional brilliant ideas that hadn't
  been tried already.  It is quite a mystery.
  
  Bill Carroll
  Chlorine Chemistry Council