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

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. Modeling Transport and Deposition – Data Requirements}
Air Modeling
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. Emissions Characteristics (1) – Four Point Sources
LABSTK
MDBSTK
BRASTK
COMSTK N
Laboratory
Brine Reduction
Area
Munitions
Demilitarization
Building
Pollution
Abatement
System
Personnel and
Maintenance

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
DFS
LIC
MPF
All furnaces have afterburners, wet pollution abatement, and carbon filters

14. Source Emission Data
Parameter
Common Stack
BRA Stack
MDB Stack
LAB Stack
Base Elevation (m)
183
182
Stack Height (m)
30.5
19.8
36.6
12.2
Gas Temperature (K)
340.1
449.8
294.3
298.7
Exit velocity (m/s)
1.75
13.01
12.73
18.3
Diameter (m)
1.52
1.37
2.19
0.64
Time of Operation (yr) 10
Emissions data collected from trial burns at UMCDF and other demilitarization sites
Particle size distribution data also collected

15. Emissions Distribution for Common Stack
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. Topography Data
Topography data taken from USGS DEM maps downloaded from Lakes Environmental (
Data imported using ISC-AERMOD View Map tool
Columbia
River
Umatilla

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. How toxic is each chemical
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 Through Sweat 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 ….
Location
Scenario
Cancer Risk
Hazard Index
Off Site
Farmer Adult
2.6E-04
0.33
Farmer Child
3.0E-05
0.41
Fisher Adult
2.1E-06
0.11
Fisher Child
1.4E-06
0.28
Native Adult
3.0E-04
Native Child
2.3E-05
0.42
Resident Adult
2.0E-06
Resident Child
On Site
1.5E-02
7.80
1.6E-03
9.84
1.2E-04
2.73
8.0E-05
6.65
1.6E-02
9.83
1.3E-03
10.00
On Site /Off Site
Worker Adult
5.2E-06
0.15
Admin Area/Off Site
Military Adult
Some areas
of concern,
lets look at
details ….

26. Hazard Index (% of Total)
Base Model Results- Point Source Contribution to Non-Cancer Chronic Risk
Stack
Hazard Index (% of Total)
Native
Adult
Child
Fisher
Farmer
Resident
BRASTK
59.4%
59.6%
59.7%
59.5%
COMSTK
1.8%
LABSTK
5.9%
MDBSTK
32.9%
32.7%
32.6%
Total HI
0.41
0.42
0.28
0.33
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)
Location
Scenario
Cancer Risk
Hazard Index
Off Site
Farmer Adult
1.5E-04
0.0038
Farmer Child
1.7E-05
0.0051
Fisher Adult
1.2E-06
0.0016
Fisher Child
7.7E-07
0.0035
Native Adult
1.6E-04
0.0050
Native Child
1.3E-05
0.0055
Resident Adult
1.1E-06
0.0013
Resident Child
On Site
8.1E-03
0.0988
8.9E-04
0.1284
6.6E-05
0.0323
4.5E-05
0.0816
9.0E-03
0.1088
6.9E-04
0.1270
On Site /Off Site
Worker Adult
4.0E-06
0.0031
Admin Area/Off Site
Military Adult
Non-cancer risks
Are all below action
levels
These operational
changes were made

29. Base Model Results- Point Source Contribution to Cancer Chronic Risk
Stack
Cancer Risk (% of Total)
Native Adult
Native Child
Farmer
Adult
Child
BRASTK
0.0%
COMSTK
100.0%
LABSTK
MDBSTK
Total CR
3.0E-04
2.3E-05
2.6E-04
3.0E-05
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
Dioxins/Furans
7,12-Dimethylbenz(a)anthracene
Benzidine
Mean if D/F are set
at detection levels
Eleven D/F and one PCB cause large increase in CSF geometric mean

31. Rethinking Assumptions (4)- Including D/F at detection limits
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
Location
Scenario
Cancer Risk (if PAH at DL)
Cancer Risk (if Not PAH)
On Site
Farmer Adult
1.8E-04
1.6E-05
Farmer Child
2.5E-05
3.1E-06
Fisher Adult
1.4E-06
1.1E-06
Fisher Child
9.7E-07
8.5E-07
Native Adult
2.0E-04
1.9E-05
Native Child
2.0E-05
2.9E-06
Combined
Worker Adult
2.7E-08
2.3E-08
Military Adult
9.7E-08
8.3E-08

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. Based On Placard Only (m)
Agent
Based On Placard Only (m)
Small Spill
Large Spill
Primary Isolation Zone (m)
Secondary Isolation Zone (m) GB 25 60
400
800
2300 VX 30
100 HD
500
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. Contact Information
Rod Skeen, Ph.D., P.E.
Division Leader
(541)
Barbara Harper, Ph.D.
(541)