1. Introduction to Brominated Flame Retardants Linda S. Birnbaum Director, Experimental Toxicology Division NHEERL Research Triangle Park, NC Region 2 Science Day/Non-Regulated Pollutants Workshop NYC – October 25, 2005 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. Flame Retardants Fires kill >3000, injure >20,000, and cause damages exceeding $11 billion annually in US alone >175 different types of FRs  Halogenated (~46%)  Phosphorus-containing (24%)  Melamines (4%)  Inorganics (27%)

3. Brominated Flame Retardants BFRs are the largest market group due to low cost and high efficiency BFRs account for 38% global demand for bromine >75 BFRs recognized commercially  Br-BPs, BDEs, CDs, phenols, phthalates,++ Global, transboundary problem  Persistence  Potential for bioaccumulation Limited Data Base

4. Global Market Demand for Major BFRs in 2001 (metric tons) [BSEF] AmericaEuropeAsiaRestoWTotal TBBPA18,00011,60089,400600119,700 HBCD2,8009,5003,90050016,700 DBDE24,5007,60023,0001,05056,100 OBDE1,5006101,5001803,790 PBDE7,100150 1007,500

5. TBBPA (Tetrabromobisphenol A) Reactive & additive  Primary use - Electronics Acute tox data – oral LD 50 : 5-10 g/kg Low chronic toxicity Not teratogenic or mutagenic Limited data in biota Dimethyl-TBBPA  Metabolite eliminated in bile  Little retained in tissues

6. Health Effects of TBBPA Immunotoxic  Inhibits T cell activation : blocks CD25 (<3µM) Hepatotoxic  Toxic to primary hepatocytes: destroys mitochondria; membrane dysfunction (inhibits CYP2C9) Neurotoxic  Inhibits dopamine uptake  Generates free radicals

7. Health Effects of TBBPA (cont.) Endocrine Disruption AhR Effects  Not relevant for commercial product (Contaminants? Combustion products?) Thyroid  TBBPA>T4 in relation to binding to transthyretin  Blocks T3 binding to TR  Perturbations observed in vivo Estrogenic  Inhibits sulfotransferase (decreases estrogen clearance)  Mostly in vitro data

8. Hexabromocylododecane (HBCD) Additive  Used in Electronics; Textile Backings Ecotox –  Algae, daphnia, NOEC = 3 ug/L  Fish, LC 50 >water solubility; PNEC=.03ug/L General Toxicity  High absorption; mild irritant and skin sensitizer; liver effects after repeated exposures (rat LOAEL ~13 mg/kg/day) Need more info: repeated dose studies, repro tox

9. HBCD (cont.) Neurotoxicity  Developmental neurotoxicant  Blocks dopamine uptake Concern for occupational settings Found in human breast milk Persistent, bioaccumulative, toxic, long range transport Isomeric composition in environmental samples differs from commercial mixture

10. Polybrominated Diphenyl Ethers (PBDEs) Major Additive BFRs(~67 metric tons/yr) DBDE – largest volume (75% in EU)  97% DBDE; 3% NBDE  Polymers, electronic equipment, textile backing OBDE  6%HxBDE; 42%HpBDE;36% OBDE; 13%NBDE;2%DBDE–multiple congeners unclear if any PeBDE)  Polymers, esp. office equipment PeBDE  Flexible polyurethane foam (up to 30%) Cushions; mattresses; carpet padding  Mainly PeBDE+TeBDE, some HxBDE Br

11. Properties Solids with low solubility ( 5) Lower congeners - more bioaccumulative, persistent Strong adsorption to soil/sediment/sludge No significant biodegradation in air/water Bioaccumulation - BCF > 5000 Long-range transport - Evidence of remote contamination (e.g., Arctic) Persistence- t 1/2 Atmospheric >2 days;Water >2 mos; Soil, sediment >6 mos

12. Sources of Environmental Release Polymer Processing Formulating/applying to textiles Volatilization and leaching during use Particulate losses over use/disposal  Incineration  Recycling

13. Pathways of Exposure? Indoor air >> outdoor air  May account for ~4%, on average, of daily intake by inhalation (could be much higher for some)  BDE209 as well as 47, 99, 100, 153, 154 House dust  Recent studies in Cape Cod, Northwest, Texas, Europe  Wide range Recent study: N = 10. Range: 705-69,000 ppb; Mean: 12,100 ppb; Median: 2,500 ppb  Levels in US, UK>>Europe, Japan  Patterns resemble commercial products (Penta, Deca)

14. Breast Milk vs. Dust (BDE 47+99+100+153+154) r=0.76 (p=0.006);not confounded by diet; (T.Webster)

15. Daily US Adult PBDE Dietary Intake (A. Schecter)

16. US Human Breast Milk PBDE levels, 2005, N=62. (A. Schecter)

17. Median Levels of PBDE 47, 99, 153 in Human Milk from Different Countries.

18. PBDEs in Human Samples Pattern of congeners is different from commercial mixtures (and food)  47>99 (others: 100,153,183, 209,…)  In some people (and biota) 153>47 Large inter-individual differences  People as high as ∑PBDEs ~10 ppm lipid!!!! Increasing time trends – levels doubling every 2-5 years PBDEs and PCBs levels are not correlated  different sources and/or time sequence North American levels ~ 10X Europe/Japan WHY?

19. (Petreas et al., 2002)

20. Ecotoxicity  PeBDE>>OBDE>DBDE  PeBDE - Highly toxic to invertebrates Larval development, LOECs in low μg/l range  DE71 – developmentally toxic to fish (1ng/l) Tail asymmetry; delayed hatching; behavioral changes; learning deficits  ∑PBDEs associated with die-off of Baltic porpoise Lymphoid depletion  BDE99 -  depletion of Vitamin E in duck eggs  BDE 47, 99, 100 -  decreases in T4/retinoids, increases in oxidative stress in Kestrals

21. Ecotoxicity (cont.) DBDE/OBDE  May be low risk to surface water organism and top predators  Concern for waste water, sediment, and soil organisms  Concerns for lower brominated congeners in OBDE, potential for debromination, and generation of PBDDs/PBDFs

22. Mammalian Toxicity in Adult Rodents Hepatotoxic Enzyme induction  UDP-glucuronyl transferase Weak inducer  Cytochrome P450 Induction of CYP2B,3A Purified BDEs are NOT CYP1A inducers DBDE – hepatocarcinogen (high dose)

23. Endocrine Disrupting Effects AhR Effects  Contamination of commercial PBDEs  Combustion can produce PBDDs/PBDFs Thyroid Homeostasis  Decrease in T4  OH-PBDE metabolites bind to transthyretin in vitro  Parent PBDEs - Effects on T4 seen in vivo Induction of UDP-glucuronyl transferase  Not a low dose effect

24. Endocrine Disrupting Effects (cont.) Progestins  In vitro – Anti-progesterone Estrogens  In vivo BDE99 – decreased E2  In vitro OH-PBDEs may be anti-estrogenic Sulfotransferase inhibition could be estrogenic

25. Endocrine Disrupting Effects (cont.) Androgens  In vivo DE71 – decreased weight of seminal vesicles and ventral prostate, decreased LH BDE99 – decreased Testosterone  In vitro DE71, BDE100, BDE47 – antiandrogenic (non-competitive inhibition)

26. Developmental Reproductive Effects DE71– pubertal exposures  Delay in puberty  Effects on male organs  Anti-androgenic in vitro – esp BDEs100, 47 BDE-99/47– in utero exposures  Delay in puberty  Ovarian toxicity  Male organ effects and decreased sperm

27. Developmental Neurotoxicity DE-71 – Rats  Deficits in sensory and cognitive function  Altered sex-dependent behaviors  Effects on thyroid, cholinergic, and dopaminergic systems BDE-99 (47,153,206,208,209) - Mice and rats  Infantile exposure (“Rapid Brain Growth”) - Permanent effects on learning  Perinatal exposure – Delay in sensory-motor development BDE-99+PCB-52 – Mice  Effects may be more than additive

28. Developmental Neurotoxicity of PBDEs Mechanisms?  Depression in serum T4  Anti-cholinergic  Anti-dopamingergic PBDEs alter cell signaling in vitro  DE71, BDEs 47, 99, 153  Altered PKC and calcium homeostasis (associated with learning and memory)  Alter phorbol ester binding

29. BDE 47 Toxicokinetics? BDE47 - Major PBDE in most people and wildlife Well Absorbed (Oral~Inhalation>Dermal) Distribution dictated by lipophilicity-  Fat Limited Metabolism -  Hydroxylation, Debromination Excretion – mice and rats differ Long Half-life-  Potential for Bioaccumulation

33. Comparative Urinary Excretion of PBDEs

35. PK of BDE 47,99, 100, and 153 Well absorbed Higher urinary elimination in mice than rats Urine elimination decreases as #Bromine atoms increase BDE99 is most metabolized What does this all mean for people?

36. New Information on Deca Deca is major PBDE in outdoor air (Butt et al., 2004) Deca can break down in the environment  Photolytic Debromination (Soderstrom et al, 2003) Matrices affect time course but not outcome BDE 154 and 183 found in all matrices; BE47 only in silica gel Deca can break down in fish  Detection of BDE-181 and 190 in carp (congeners not in commercial products) (Rice et al, 2002)  7 penta to octa metabolites found (Stapleton et al, 2003) Deca can be absorbed (>10%) and break down in rodents  Debrominated, Hydroxylated, Methoxylated  Reactive Intermediates -  Covalent binding Deca MAY BE developmentally neurotoxic

38. DBDE in Human Samples Rarely Measured – but its there! Serum  Levels as high as 200ppb lipid in occupational exposed workers Breast Milk  Mean~0.9 ppb lipid Analytical Issues  High background levels in dust lead to laboratory contamination

39. Potential Health Risk of PBDEs Top 5% of current human exposure in US - >400 ng/g lipid  If humans are 25% lipid, then their “dose” is ~0.1 mg/kg body weight Significant dose causing DNT  Mice < 0.8 mg BDE99/kg  Rats <0.7 mg BDE47/kg Preliminary Developmental Repro ~.06mg/kg Rodent body burdens associated with DNT are only ~10X higher that total PBDE body burdens in people in North America Margin of exposure for PBDEs appears low Additional concern: are PBDEs interacting with other PBTs?

40. Conclusions Growing international concern  P, B, and T Presence in biota Presence in human tissues  North American levels much higher than Europe or Japan  Relative Biotic levels are very different from commercial mixtures Increasing potential for health effects

41. With Special Thanks NHEERL  Daniele Staskal, Janet Diliberto, Mike Devito, Vicki Richardson, Kevin Crofton, Tammy Stoker, Prasada Kodavanti EPA HQ  Dan Axelrad, Tala Henry, Hend Galal-Gorchev NIEHS  Tom Burka, Mike Sanders, Ed Lebetkin, John Prichard USDA  Heldur Hakk, Janice Huwe UT  Arnie Schecter BU  Tom Webster Cal EPA  Tom McDonald Duke  Heather Stapleton And all of my colleagues worldwide!