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Mark Mahoney – EPA New England Dioxin and Backyard Burning Vermont Forum on Open Burning May 17, 2004.

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Presentation on theme: "Mark Mahoney – EPA New England Dioxin and Backyard Burning Vermont Forum on Open Burning May 17, 2004."— Presentation transcript:

1 Mark Mahoney – EPA New England Dioxin and Backyard Burning Vermont Forum on Open Burning May 17, 2004

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

3 3 Some consider this an issue of the past.

4 4

5 5

6 6

7 7

8 8 State-of-the-Art Burn Box

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

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

11 11 2,3,7,8-Tetrachlorodibenzo-p-dioxin Cl O O PCBs 209 congeners 12 toxic 3,3',4,4'-TeCB 3,3',4,4',5-PeCB 3,3',4,4',5,5'-HxCB Plus 8 others Cl 3,3',4,4',5,5'-Hexachlorobiphenyl Dioxin-like Compounds Dioxins 75 congeners 7 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 Furans 135 congeners 10 toxic 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 Cl 2,3,7,8-Tetrachlorodibenzofuran O

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

13 13 USEPAs Dioxin Reassessment The Good News: The Good News: The average bioaccumulation level in humans has dropped from 55 ppt (in the 1980s) to 25 ppt (1990s) The Bad News: 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: The Bottom Line: We need to take more steps to further reduce dioxin exposure.

14 Key Findings of the Reassessment: Key Findings of the Reassessment: 95% of General Population Exposure is from animal fats in the commercial food supply 95% of General Population Exposure is from animal fats in the commercial food supply Local sources make little contribution to most peoples exposure Local sources make little contribution to most peoples exposure Environmental levels in meat and dairy production areas major contributor 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 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 Reservoir sources are a significant component of current exposure and may dominate future exposure 8

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

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

17 Key Findings of the Reassessment 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. 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 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. 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 (1 in 1,000) from background (dietary) exposure. True risks are likely to be less but we cant say how much less but may approach zero for some individuals (very low exposure/very low susceptibility). Based on epidemiologic data, probability of cancer risk to the general population may exceed (1 in 1,000) from background (dietary) exposure. True risks are likely to be less but we cant say how much less but may approach zero for some individuals (very low exposure/very low susceptibility). Key Findings of the Reassessment: Risk Characterization Key Findings of the Reassessment: Risk Characterization 10

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

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

21 Fluxes among dioxin reservoirs

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

23 23 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 TEQ DFP /g lipid) Steady state PK modeling of current intake levels project tissue levels of about 11 pg TEQ DFP /g lipid. Dioxin Exposure Trends

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

25 Draft Estimate: ~ 65 pg TEQ DFP -WHO 98 /day 21% 16% 19% 14% 5% 4% 7% 6% 1% Soil ingestion Soil dermal contact Freshwater fish and shellfish Marine fish and shellfish Inhalation Milk Dairy Eggs Beef Pork Poultry Other meats Vegetable fat Adult Average Daily Intake of CDDs/CDFs/Dioxin-like PCBs

26 26 Location of Lakes for Sediment Core Sampling

27 27 Non-detects = zero Year Residue Levels (pg/g, dw) Total CDD/Fs Sediment Levels, Beaver Lake, Olympic Peninsula

28 28

29 29

30 30 Known Sources of Dioxin

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

32 32 OPEN BURNING TEST FACILITY

33 33 Open Burn Test Facility

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

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

36 36 -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). Activity Level

37 37 Dioxin Uptake Into Meat And Dairy

38 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 39 Uncontrolled Controlled

40 40 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. Summary and Conclusions

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

42 Together we can : Ban the Barrel Thank you


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