Future Science Issues of BFRs

1
Future Science Issues of BFRs

• Linda S. Birnbaum
• Director, Experimental Toxicology Division
• NHEERL
• Research Triangle Park, NC
• Region 2 Science Day/Non-Regulated Pollutants
  Workshop
• NYC October 25, 2005

2
Why BFRs?

• Flame retardants save lives
• Many classes of FRs
• BFRs most cost effective
• gt75 different BFRs
• Br-BPs, BDEs, CDs, phenols, phthalates,

• Global, transboundary problem
• Persistence
• Potential for bioaccumulation
• Limited data base

3
TBBPA

• Extensive Ongoing Studies under FIRE

4
HBCD

• Persistent Bioaccumulative Potentially Toxic
• Science Needs
• Exposure Information
• Toxicity Studies

5
HBCD in 30 Canadian Human Milks (ppb lipid)(Ryan
and Patry, 2002)
Mean Median Min Max
6.6 1.3 0 126
6
PBDEs

• Penta and Octa
• No longer produced in US, but continued use
  allowed
• Persistence and bioaccumulation --? continuing
  concern

7
Penta and Octa Science Questions

• How are the congeners getting into the
  environment?
• Environmental fate and transport?
• Pathways of human exposure
• DustgtDiet???
• Modes of action for toxic effects

8
BDE Structures
BDE 47
BDE 153
BDE 100
BDE 99
9
Commercial Mixture vs. Humans
Media BDE Congeners () BDE Congeners () BDE Congeners () BDE Congeners () BDE Congeners ()
Media 47 99 100 153 154
Commercial PentaBDE 37 48 8 4 3
Human Tissue 54 14 8 20 4
Hites 2004

• WHY THE DIFFERENCE?
• Environmental degradation/debromination?
• Altered toxicokinetics?
• Are most people like mice or rats?

10
Deca

• High volume product
• Worldwide presence
• PPM concentrations in sediment
• PPB concentrations in biota

11
Deca Science Questions

• Deca Breakdown
• Photolytically
• Microbially
• Metabolically
• Is Deca (BDE209) itself toxic?
• What about Deca Metabolites/ Breakdown Products?

12
Potential Health Risk of PBDEs

• Margin of exposure for PBDEs appears low
• Additional concerns
• Are PBDEs interacting with other PBTs?
• Contamination with Brominated Dioxins/Furans