Dioxin and Backyard Burning Vermont Forum on Open Burning May 17, 2004

1. Dioxin and Backyard BurningVermont Forum on Open BurningMay 17, 2004 Mark Mahoney – EPA New England

2. Topics • What is dioxin? • Why is dioxin a unique pollutant? • Health Effects • Exposure Pathways • Environmental Sources • Importance of Barrell Burning

3. Some consider this an issue of the past.

8. State-of-the-Art Burn Box

9. Why are we Concerned? • Backyard burning causes accidental fires. • Backyard burning releases toxic chemicals into environment that can cause adverse health impacts. • Backyard burning is illegal in many states and counties.

10. Release of Toxic Chemicals • Particulate Matter • Sulfur Dioxide • Carbon Monoxide • PAHs • Metals • Hexacholorobenzene • Dioxin Direct Exposure Indirect Exposure

11. Cl Cl O Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl O O Cl Cl 2,3,7,8-Tetrachlorodibenzo-p-dioxin 3,3',4,4',5,5'-Hexachlorobiphenyl 2,3,7,8-Tetrachlorodibenzofuran Furans 135 congeners 10 toxic Dioxins 75 congeners 7 toxic PCBs 209 congeners 12 toxic 2,3,7,8-TCDD 1,2,3,7,8-PeCDD 1,2,3,4,7,8-HxCDD 1,2,3,6,7,8-HxCDD 1,2,3,7,8,9-HxCDD 1,2,3,4,6,7,8-HpCDD 1,2,3,4,6,7,8,9-OCDD 2,3,7,8-TCDF 1,2,3,7,8-PeCDF 2,3,4,7,8-PeCDF 1,2,3,4,7,8-HxCDF 1,2,3,6,7,8-HxCDF 1,2,3,7,8,9-HxCDF 2,3,4,6,7,8-HxCDF 1,2,3,4,6,7,8-HpCDF 1,2,3,4,7,8,9-HpCDF 1,2,3,4,6,7,8,9-OCDF 3,3',4,4'-TeCB 3,3',4,4',5-PeCB 3,3',4,4',5,5'-HxCB Plus 8 others Dioxin-like Compounds

12. What is Dioxin? • A group of chlorinated organic compounds including dioxins, furans, and some PCBs. • Produced when materials containing chlorine are burned • Occur naturally and from combustion of fuels & waste, paper making, and other chemical and industrial processes.

13. USEPA’s Dioxin Reassessment • The Good News: The average bioaccumulation level in humans has dropped from 55 ppt (in the 1980’s) to 25 ppt (1990’s) • The Bad News: The level at which health effects are detectable in humans is considerably lower than previously estimated. Consequently, current exposures are still of concern. • The Bottom Line: We need to take more steps to further reduce dioxin exposure.

14. Key Findings of the Reassessment: 95% of General Population Exposure is from animal fats in the commercial food supply Local sources make little contribution to most peoples’ exposure Environmental levels in meat and dairy production areas major contributor Air deposition onto plants consumed by domestic meat and dairy animals is the principal route for contamination of commercial food supply Reservoir sources are a significant component of current exposure and may dominate future exposure 8

15. Modes of Action of Dioxin AIP,.. TCDD, ... hsp90 Other Proteins AhR hsp90 Arnt HIFa, Sim,... Transport Mechanism RB, ... AIP,.. hsp90 O O O O Cl Cl Cl Cl Cl Cl Cl Cl phosphorylation/ dephosphorylation Cl Cl Cl Cl Cl Cl Cl Cl O O O O hsp90 chromatin Co-activators Co-repressors Differentiation and Proliferation AhR BTFs Arnt BTFs DRE TATA Changes in protein levels (e.g., CYPIA1, IL-1, ...) Altered gene expression mRNA

16. Lethality Wasting Gonadal/Lymphoid Atrophy Hyperplasia Metaplasia Endocrine disruption Carcinogenicity Reproductive/ Developmental toxicity Dermal toxicity Immunotoxicity Neurotoxicity Hepatic toxicity Cardiovascular toxicity Toxic Effects of Dioxins Multiple effects in multiple tissues of both sexes of multiple species throughout the vertebrate kingdom

17. Key Findings of the Reassessment Adverse non-cancer effects have been observed in animal and humans within 10 times background exposure. It is likely that part of the general population is at, or near, exposure levels where adverse effects can be anticipated. 9

18. Key Findings of the Reassessment: Risk Characterization Cancer slope factor is based primarily on published analyses of human studies and is revised upward by a factor of ~6 over the 1985 EPA value. Uncertainty in the value but MOEs for cancer are low. Based on epidemiologic data, probability of cancer risk to the general population may exceed 10-3 (1 in 1,000) from background (dietary) exposure. “True” risks are likely to be less but we can’t say how much less but may approach zero for some individuals (very low exposure/very low susceptibility). 10

19. Key Findings of the Reassessment: Current US regulatory efforts have addressed most of the known large industrial sources (~80% reduction between ’87 and ’95; further reductions (>90%) anticipated). Open burning of household wastes is the biggest unaddressed contemporary source identified so far. There remain many uncharacterized sources that could be significant (agricultural burning, ceramics, forest fires, secondary steel, reservoir sources). 7

20. Sources and Pathways to Human Exposures SOURCES DEPOSITION FOOD SUPPLY TRANSPORT Reentrainment Runoff Erosion

21. Fluxes amongdioxin reservoirs

22. Pathways and Sources of Human Exposures • Pathways: • Ingestion of soil, meats, dairy products, fish • Inhalation of vapors and particulates • Dermal contact with soil • Sources: • Combustion • Metal Smelting, Refining, Processing • Chemical manufacturing • Biological and Photochemical Processes • Reservoir sources

23. Dioxin Exposure Trends • Environmental levels: • Peaked in late 60s/early 70s; declined since based on sediment data • Decline also supported by Emissions Inventory which shows significant decrease from 1987 to 1995 (~80%) • Human tissue data suggest current levels are about half of 1980 levels (55 to 25 pg TEQDFP/g lipid) • Steady state PK modeling of current intake levels project tissue levels of about 11 pg TEQDFP/g lipid.

24. Data for Archived Food Samples (results assume ND = ½ LOD; results calculated at ND = 0 shown in parenthesis).

25. Soil ingestion Vegetable fat Soil dermal contact Other meats Poultry Freshwaterfish and shellfish 6% Pork 5% 19% Marine fish and shellfish Beef 7% 14% 1% Inhalation 4% 16% Eggs 21% Milk Dairy Adult Average Daily Intake of CDDs/CDFs/Dioxin-like PCBs 2000 Draft Estimate: ~ 65 pg TEQDFP-WHO98/day

26. Location of Lakes for Sediment Core Sampling

27. Sediment Levels, Beaver Lake, Olympic Peninsula 200 180 160 140 120 100 Residue Levels (pg/g, dw) 80 60 40 20 0 1884 1897 1909 1921 1932 1946 1955 1964 1974 Year Total CDD/Fs Non-detects = zero

30. Known Sources of Dioxin

31. BYB Emissions are Greater Than All Other Quantified Sources Combined All other sources BYB

32. OPEN BURNING TEST FACILITY

33. Open Burn Test Facility

34. Open CaCl2 CaCl2 Wetted Wetted Double Double Double High Cu High Cu PVC=1% PVC=0% PVC=0% PVC=1% Baseline Baseline Baseline Baseline Baseline Baseline Baseline PVC=7.5% PVC=7.5% Compressed Compressed Results: TEQ Values 10000 1000 I-TEQ (ng/kg waste burned) 100 10 1

35. Statistical Analysis Results • Waste Chlorine Effect Statistically Significant Only at High Cl Levels • At Normal Cl Levels (< 1 % Cl), Other Parameters Dominate • Gas-Phase Conditions Important (HCl, T, Cu, burning rate) • Majority of PCDD/F Emissions During Smoldering Phase of Burn

36. Activity Level • -In 2000, 51.8 Million People Lived in Nonmetropolitan Areas (U.S. DOC, 2000). • -Of the Rural Population in the United States, 40 Percent Are Assumed to Burn Their Household Waste in a Barrel (Two Rivers Region Council of Public Officials 1994). • -On Average, Each U.S. Citizen Generates 4.5 Pounds of Solid Waste (Excluding Yard Waste) Per Day (or 616 kg/person-yr) (U.S. EPA, 2001). • -On Average, in Households that Dispose of Household Waste by Burning, Approximately 63 Percent of Waste Generated Is Burned (I.E., 63 Percent of 616 Kg/person-yr = 388 Kg/person-year) (Two Rivers Region Council of Public Officials 1994).

37. Dioxin Uptake Into Meat And Dairy

38. Emissions from Known Sources Unlikely to Correlate Proportionally With General Population Exposures. • A Majority of the Combustion Sources Are Limited to a Few States • The Production of Animal Fats Is Also Concentrated in a Few States • Most Major Food Production States Are Are Upwind of Major Emission Production States • Open Burning Likely to be a Significant Source of Exposure • Reservoir Sources Could Be Significant Source of Exposure

39. Uncontrolled Controlled

40. Summary and Conclusions • Dioxin-like Compounds are Highly Potent Carcinogens and exhibit a wide range on non-cancer health effects. • Dioxin-like Compounds Background exposure levels result in significant risk. • Exposure is from consumption of animal fats in the commercial food supply. • Environmental levels have declined since the '70s but may level off as major industrial emission sources are controlled. • Uncontrolled combustion is likely to be the largest unaddressed contemporary sources. • Backyard burning of household waste is the best understood and likely the most amenable to reduction of all uncontrolled combustion sources.

41. What Can YOU Do? • Share the message • Identify other waste disposal methods in your community • Reuse (more use means less waste) • Recycle (paper, plastics, metallic items) • Compost (leaves, yard waste, vegetable wastes) • Identify local landfills which accept waste

42. Together we can :“Ban the Barrel” Thank you