Re: Does dioxin toxicity increase in the environment??

[Alan Watson <alanwatson@gn.apc.org>]

  My earlier post was incomplete and lacked these references - sorry:
  
  Some work has been done on photolytic degradation to potentially more 
  toxic congeners by:
  
  Miller, G.C., Herbert,V.R. Mueller, M., Mitzel, R., Zepp, R.G. (1989).  
  Photolysis of octachlorodibenzo - p- dioxin on soils: Production of 
  2,3,7,8 - TCDD.  Chemosphere, 18,1265
  
  Bueser, H.R. (1976) Preparation of qualitative standard mixtures of 
  polychlorinated dibenzo-p-dioxins and dibenzofurans by ultraviolet and 
  irradiation of the octachloro compounds. J. Chromatography., 129,303.
  
  Bueser, H.R. (1979) Formation and Identification of tetra- and 
  pentachlorodibenzo-p-dioxins from photolysis of two isometric 
  hexachlorodibenzo-p-dioxins.  Chemosphere,4,251.
  
  Whilst these tend to be accelerated lab studies with high UV input it 
  seems plausible that similar reactions could take place in the 
  environment over longer periods of time.
  
  Could it be possible, for example, that an increase in TEQ in the 
  environment  could explain some of the discrepancies between current 
  emission and deposition inventories?
  
  If this does happen how can you possibly regulate dioxin emissions on a 
  TEQ basis - the limits would be meaningless in real terms.
  
  Any comments on this would be greatly appreciated!
  
  Best wishes
  
  Alan
  
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         _\\|//_                Alan Watson C.Eng                  
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