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Dioxin '97 Presentation by USEPA Policy Analyst, Dwain Winters (fwd)

  This is a summary, done by Pat Costner of Greenpeace, of an EPA
  presentation at Dioxin'97. 
  Following are various points from Dwain's overheads and presentation. 
   I could not reproduce it in this format, however, Dwain presented a 
  final diagram showing that, among the kinds of sources of PCDD/Fs and 
  PCBs [reservoir sources, unknown sources, and known sources], the 
  on-going focus of risk management is known sources.   [This could be 
  interpreted to mean that USEPA may well think that the major sources 
  are identified and that further efforts toward source 
  identification/quantification are not necessary..]  It is also 
  interesting to note that Dwain groups USEPA's new approach, margin of 
  safety, with the precautionary principle as risk management paradigms 
  with no acceptable increment of risk.  Based on  Tom Webster's 
  explanation of margin of safety, this is not actually the case.
  The key point in Dwain's presentation was the question he posed:  
  How will USEPA judge small increments in exposure against the 
  background exposure when that background is increasing or decreasing? 
   And the key phrase is "when that background is increasing or 
   From the presentations by Farland and Cleverly, it is 
  certain that USEPA is contending that background exposures are 
  decreasing rapidly:  whatever USEPA and industry has done to 
  reduce dioxin releases is working well, so no new, stronger measures 
  are needed.  
  This probable USEPA perspective must be viewed in conjunction with 
  the presentation by Germany's Furst.  He reported that, 
  although Germany has achieved it's goal of reducing PCDD/F (TEQ) 
  intake to 1 pg/kg bw/day, the intake of breastfeeding infants 
  is still almost 70 pg/kg bw/day.   Following his session, I asked if 
  he or any of his colleagues had estimated an adult daily intake that 
  would result in intakes for breasfeeding infants of 1 pg/kg bw/day.  
  He smiled and said no, he had not made such calculations but that 
  such an intake would be "very, very low."
  Dwain Winters, USEPA policy analyst, Presentation at Dioxin '97, 
  International Dioxin Symposium, Indianapolis, Indiana, Aug. 24-29, 
  Characteristics of Dioxin Policy
  · Maturing scientific and technical base
  · Established risk management programs
  · Cross media problem
  · Multitude of stakeholders
  Cross Media Policy Issues
  · General Population Exposure
  · Special Population Exposure
  · Cancer & non-cancer effects
  General Population Exposure
  *  Atypical for Background Risk
        Level of risk
        Cross media origin
  *  How should we judge risk significance
        Risk management paradigms
  Risk Management Paradigms
    No  acceptable increment of risk
     - Margin of safety
     - Precautionary Principle
    An Acceptable Level of Risk
    - De Minimis Risk
  Risk-Benefit Balancing
    - TSCA
    -  RIA
  Technology-Based Rulemaking (most dioxin regulation in US is based
   on this approach, which is technology-based, not risk- or 
    - MACT [maximum achievable control technology]
    - Effluent guidelines
  Special Population
    - Equity-based concerns
    - Tied to decisions on general population
    -  Requires information on local scale
  How to judge small increments against background (when background is 
  increasing or decreasing)
  Cancer and non-cancer risks
    - Cancer - probabilistic (chose point when risk is no longer of concern)
    - Non-cancer - deterministic (presence or absence of thresholds)
    - Talks about non-cancer effects in probabilistic terms?
  Targeting future actions
    Emission-based targeting
    Risk-based targeting
   Where to target - emissions or risk?
  Pat Costner
  P.O. Box 548, or 512 CR 2663
  Eureka Springs, Arkansas 72632 USA
  ph:  501-253-8440
  fx:  501-253-5540
  em:  pat.costner@dialb.greenpeace.org