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Rodney Skeen May 2013

Application of AERMOD to Native American Human Health Risks from Chemical Weapons Incineration at the Umatilla Chemical Depot. Rodney Skeen May 2013. Presentation Overview. Background on CTUIR and UMCD Human health risk assessment basics Site specific data Human health risk results

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Rodney Skeen May 2013

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  1. Application of AERMOD to Native American Human Health Risks from Chemical Weapons Incineration at the Umatilla Chemical Depot Rodney Skeen May 2013

  2. Presentation Overview • Background on CTUIR and UMCD • Human health risk assessment basics • Site specific data • Human health risk results • Process modification to reduce risk • AERMOD and Transportation Risk • Summary

  3. Historical Territory of the CTUIR UMCDF Reservation

  4. Umatilla Depot (UMCD) • Army granted 14,000 acres in 1941 for munitions depot (expanded to over 19,000) • Chemical munitions have been stored since 1962 • Site stored 12% of the original U.S. stockpile of chemical agents • Nerve agents GB (sarin) and VX • Blister agent HD • On-site incinerator destroying munitions • Incinerator started in 2004, operated until 2012, full closure complete in 2014.

  5. What operating conditions for the UMCDF ensure that emissions do not create unacceptable risks to surrounding populations? Simple Question to Answer

  6. Acceptable Limits • 2004 HHRA Work Plan established the following limits: • No individual Cancer Risks above 1E-6 • Total Cancer Risk below 1E-5 • Individual Hazard Quotient below 0.25 • Total HI for specific effect and organ below 0.25 • Acute Inhalation HQ for individual compounds below 1.0 • Ecological Screening Quotients below 1.0

  7. Example Conceptual Model

  8. Steps to Risk Assessment • Identify emissions characteristics (flow rate, particulates, composition, temperature, etc) • Model contaminant transport and deposition through the air • Estimate exposure mechanisms • Exposure routs (inhalation, dermal contact, ingestion) • Lifestyle • Estimate toxicity of each compound • Compute dose and risk

  9. } Air Modeling Modeling Transport and Deposition – Data Requirements • Meteorological data • Topography data • Land use • Building geometric data • Source geometry data • Source emission data • Risk data

  10. Tools in Risk Assessment • Air transport and deposition modeled using Lakes Environmental implementation of AERMOD • Risk and ecological risks modeled using modified versions of Lakes Environmental IRAP-h and EcoRisk

  11. MDBSTK COMSTK Munitions Demilitarization Building Pollution Abatement System LABSTK Brine Reduction Area Laboratory BRASTK Personnel and Maintenance Building N Emissions Characteristics (1) –Four Point Sources

  12. Emission Characteristics (2) – Common Stack • Common stack receives emissions from four very different furnaces (Liquid incinerators 1&2, Deactivation Furnace, Metal Parts Furnace) • Use of each furnace varies by type of munitions begin processed • Time weighted scaling methodology was developed to estimate a single emissions rate for evaluating chronic risks • Upset for each furnace evaluated separately for estimating acute risks

  13. Emission Characteristics (2) –Common Stack Furnaces • All furnaces have afterburners, wet pollution abatement, and carbon filters DFS LIC MPF

  14. Source Emission Data • Emissions data collected from trial burns at UMCDF and other demilitarization sites • Particle size distribution data also collected

  15. Common Stack Emission Distribution – What you don’t know may kill you.... Emissions Distribution for Common Stack (Based on HHRA Values) Less than 2% of emitted organics were identifiable

  16. Meteorological Data (1) • Six years of on-site surface data • 2 meter temperature • 10 meter speed, direction, STDEV, temperature • 30 meter speed, direction, STDEV, temperature • Solar insulation, precipitation, pressure • Upper air data from Spokane Washington • Merged using AERMET View

  17. Columbia River Umatilla River Topography Data • Topography data taken from USGS DEM maps downloaded from Lakes Environmental (www.webgis.com) • Data imported using ISC-AERMOD View Map tool

  18. Land Use Water Body Range Land Agricultural Land

  19. Example Deposition Map – Unitized Vapor Phase Air Concentration (ug/m3 per g/s)

  20. Deposition Grid and Evaluation Points Receptor Locations 50 km

  21. Estimating Exposure (Dose) Scenario Exposure Where you go × = DOSE RISK What you do What contaminants are in each medium – air, water, soil, food… How toxic is each chemical What you eat

  22. Accounting for Cultural Contact Harvesting Drying Cooking

  23. Cultural Contact ThroughSweat Lodge Activity • Characteristics • 100% humidity • 150 F • Active behavior Water Rocks

  24. Native American Subsistence Scenario (NASS) • Live 70 years in one location (whole life) • Active lifestyle • No vacation • 100% of produce grown locally • 100% Meat/Fish from impacted area • Different dietary pattern • Higher caloric intake (2500 kcal/day). • High fish intake • Consumption of whole animal • Unique exposure pathways • Sweat lodge • Native medicines • Cultural practices (hunting, fishing, gathering, weaving, tanning)

  25. Base Model Results Some areas of concern, lets look at details ….

  26. Base Model Results- Point Source Contribution to Non-Cancer Chronic Risk • BRA stack was the largest point source contributor. • GB, VX, and HD created more than 99% of the non-cancer risk, but are undetected compounds assumed present at just below the detection limit for the continuous monitoring units.

  27. Rethinking Assumptions (1) • Reviewed process data and realized that the confirmatory agent monitoring system has lower detection limit. These units rely on a collection tube and are periodically sampled. • Off-site shipment of brine for treatment is viable alternative to operation of Brine Reduction Area (BRA) • Re-analyzed risk at lower HD/GB/VX emission levels and no BRA operation during HD campaign

  28. Rethinking Assumptions (2) • Non-cancer risks • Are all below action • levels • These operational • changes were made

  29. Base Model Results- Point Source Contribution to Cancer Chronic Risk • Over 99% of the cancer risk from COMSTK is a result of the unidentified non-volatile TOE fraction which was assigned a surrogate toxicity based on geometric mean of the compounds in the corresponding boiling point group • EPA Guidance does not require quantitative evaluation of this fraction because of its uncertainty. Was evaluated by Army because of CTUIR concerns

  30. Rethinking Assumptions (3) –CSF of Unidentified Non-Volatile Organic • Eleven D/F and one PCB cause large increase in CSF geometric mean Dioxins/Furans 7,12-Dimethylbenz(a)anthracene Benzidine Mean if D/F are set at detection levels

  31. Unspeciated Computed from total mass measurement Rethinking Assumptions (4)- Including D/F at detection limits • ACTION: Modified sampling and analysis methods to identify more of the organic fraction and to lower detection limits. • GravFrac=Polystyrene? (FTIR) • Included D/F and other PAH compounds at their Detection Limit • Two on-site scenarios still predicted to be above action levels • 99% of predicted risk still driven by unidentified non-volatile organic • Unidentified means the real risk is uncertain • FTIR suggests unspeciated is polystyrene

  32. Closure Sampling Area • Remaining Compounds of concern have resulted in implementing a closure sampling strategy in the zone of potential plume deposition • Soil Sampling Results will be used for risk based closure.

  33. Modeling Truck Accident and Chemical Agent Spill with AERMOD Vapor Concentration Exposure Point Emission Rate (g/s) Point or Area Source Exposure Time

  34. USDOT Emergency Response Guidebook Exposure Scenarios • Concerned Motorist - 10 minutes of exposure in spill area • First Responder – 1 hour at 25 meters • General Public – 2 hours at maximum concentration within 50 m and Secondary Isolation Boundary. First Responder Scenario evaluated at 25 m Primary Isolation Zone Boundary. 50 m Boundary Spill Area Concerned Motorist Scenario Evaluated Within Spill Area. Evaluation • Compared dose with Acute Exposure Guideline Levels General Public Scenario Evaluated Within the Area Between 50 m and the Secondary Isolation Zone. DOT Secondary Isolation Zone (Set by First Responders)

  35. Conclusions • AERMOD used to model emission from a chemical munitions incinerator at Umatilla, Oregon • Emissions use to evaluate future health risks to Native Americans using the impacted lands. • Risk results led to operation changes and modified closure strategy. • AERMOD also applied modeling plume development

  36. Rod Skeen, Ph.D., P.E. Division Leader (541) 429-7420 rodskeen@ctuir.org Barbara Harper, Ph.D. Division Leader (541) 429-7950 Barbaraharper@ctuir.org Contact Information

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