0. Adherence to the Scientific Method while Advancing Exposure Science
Daniel A. Vallero, Ph.D
U.S. Environmental Protection Agency
National Exposure Research Laboratoy

1. Scientific method
Science is more than inquisitiveness and explanation of the world around us….
“When we explain something, as science strives to do, we gain, or at least attempt to gain, power over that entity.
Understanding how a molecule is structured allows for efficacious medicines and treatment of cancer.
“Indeed, the basic scientist may see ‘control’ and ‘power’ as motivators for all science….”
“One of the principal values of the scientific method is that the process is aboveboard and objective. It encourages scientists to be careful to guard the public trust.”

2. Scientific method (cont’d)
Beware of “settled science”
“Indeed there can be arguably some level of consensus,
but nothing near unanimity in any scientific discipline especially when the underlying theory is still evolving and the uncertainties still need to be reduced by experiment and observation. Indeed, the thoughtful scientist must ask what exactly is supposed to be ‘settled’.”
Compare this to CP Snow:
“The only ethical principle which has made science possible is that the truth shall be told all the time. If we do not penalize false statements made in error, we open up the way, don’t you see, for false statements by intention. And of course a false statement of fact, made deliberately, is the most serious crime a scientist can commit.”

3. Exposure science
So, where does that leave us in advancing exposure science?
Adapted from: D.E. Stokes (1997). Pasteur’s Quadrant. The Brookings Institution, Washington, DC
Domain of exposure science?

4. Risk is a function of hazard and exposure
Hazard Identification
Dose Response Assessment
Exposure Assessment
Risk Characterization
Source Characterization
Risk Management Decisions
Lioy: No contact, no exposure…..
Risk Management Options ID’d
Risk Management Options
Cost and Effectiveness Assessment

5. Disaster Preparedness & Response
Disaster -> Low-probability events with high-value consequences
Disruption of Normal Conditions
Human suffering and/or property damage
Exceeds the capacity of the affected community to respond without outside resources.

6. Disaster Preparedness & Response
Disaster -> Low-probability events with high-value consequences
Disruption of Normal Conditions
Human suffering and/or property damage
Exceeds the capacity of the affected community to respond without outside resources.
So then, when does a “problem” become a “disaster”?

7. Disaster Preparedness & Response
When risks that are not properly managed result in significant physical damage to human life, ecosystems, and materials.

8. Disaster Preparedness & Response
Thus, decision makers must consider human and environmental vulnerability.
This can prevent or minimize the probability of accidents, reduce the consequences, allow for disaster control, and take steps to mitigate when accidents occur.
Disasters have the potential to cause global, long- term, and even irreversible impacts.

9. Disaster Preparedness & Response
Disasters vary in scale and complexity
Have the potential to cause global, long-term, and even irreversible impacts.
Harkens of the precautionary principle.

10. Species Extinction
Climate Change
Stratospheric Ozone Depletion
Accidents can lead to global radioactive impacts, global human losses, multi-generational impacts, invasive species, and species extinction
Global
Spatial Scale
Persistent Bioaccumulative Toxins
Regional
Acidification
Smog
Particulate Impacts
Air Toxics
Fossil Water Aquifer Depletion
Ecotoxicity
Local
Microenvironmental exposures
Centuries
Hours
Years
Temporal Scale
Accidents relative to other environmental issues. Some accidents (and their indirect effects) have the potential to cause global, long term (even irreversible) impacts.

11. Exposure Science Needs vary by stage.
Sampling and analysis approaches vary.
Varies by who needs protection.
Quality of science depends on time.
But, health decisions are often based on insufficient and misleading information.

12. Information Problems
Increase as the magnitude of the event unfolds and the severity of the of the event becomes more apparent
Affected by amount and quality of the data and interpretation of the data
Limited communication, especially in early stages– short wave radio (in worst and largest events) to wireless and web based systems
Surveillance after an event starts as soon as possible and cycles as time and data becomes more readily available
Information quality affects operational decisions

13. Exposure needs vary by stage:
Rescue
Recovery
Re-entry
Restoration
Re-habitation

14. Improvements Automated equipment tracking system Rapid response team
Improved portable and flexible emergency response platform and personal monitors
Improved and new sensor technologies
Revisions to national contingency plans
Beginning to adapt occupational exposure standards to environmental conditions (e.g. PELs, AEGLs for communities)
Established indoor and ambient clean up protocols
Better communication devices (less reliance on land lines)
Computational methods
National Decontamination Program’s simulations. However, this needs to be expanded substantially to numerous communities and for various types of disasters

15. Rescue Basic measures to preserve life and function
Triage –essential in large disasters – Field stabilization
Portable, state of the art equipment and expertise provided to first responders (US Coast Guard, Homeland Security, Regional Superfund Response Team)
“Research” put on hold
Same tools often applied, but at higher levels of detection and more immediate reporting
Crime scene, forensics and rescue efforts have primacy
Responder protection is utmost importance
Proper respirators and personal protection
Protocols
Very different from “environmental exposures” (e.g. levels of dioxins and benzene to protect firefighters with PPE are much higher than a person without protection exposed for 30 years)

16. Recovery
Somewhat more time, but still working under First Responder teams
Logging data and retrospectively conducting analyses
Different quality assurance needs, but still not the “typical” research design
Crime scene forensics still ongoing (defer to Police, FBI and Homeland Security), but more deliberate
- In WTC, evidence moved to Staten Island
Adaptation to FEMA and other management actions
- In Katrina, U.S. Army Corps of Engineers proposals (e.g. possible exposures to asbestos from cleanup options versus exposures from waiting…)

17. Re-Entry Even more time
Closer to typical research protocol, but must not hinder local and Regional Office activities and decisions
Region 2 made decision to require HazMat level of cleanup before re-entry
Benchmarks are crucial
Understandable
Allows for risk comparisons
Helps distinguish reported concentrations from reasonable exposures.

18. Benchmarks Use identified guidelines/standards where available
In WTC Response:
AHERA school re-entry standard for airborne asbestos
OSHA/EPA definition of ACM for bulk material
NAAQS for ambient air sampling (Pb, CO, PM2.5) in residential areas
OSWER residential guidelines for dioxin, PCBs and lead in dust/bulk material
OSHA PELs (TWA) for air samples taken on the debris pile (worker exposure)
Federal Ambient Marine Water Quality Criteria and historical Hudson River data
Federal MCLs for drinking water samples
NPDES permit limits

19. Benchmarks When identified guidelines/standards absent:
Developed risk-based screening levels
E.g. for residential scenario used EPA Hazard Evaluation Handbook (1 & 30 year exposure for carcinogens)
Example for dioxin:
30 year screening value for ambient air: ng/m3
1 year screening value for ambient air: ng/m3
Similar approach used for air values for PCBs, benzene, other VOCs, semi- volatile compounds, and metals
Compare to background (e.g. annual NAAQS and air toxics measurements at nearby sites)

20. Challenge of benchmarks
Without benchmarks
Fail to grasp a real environmental problem that exists
Perceiving a problem even when things are better than or do not differ significantly from those of the general population.

21. Avoiding false negatives:
What if measurements indicate no harm, but in fact toxic substances are in the air we are breathing?
What if this substances that have been identified really do cause cancer but the tests are unreliable?
What if people are being exposed to a contaminant, but via a pathway other than the ones being studied (e.g. exposed to volatile

22. Avoiding false positives:
What if previous evidence shows that an agency had listed a compound as a carcinogen, only to find that new information is now showing that it has no such effect?
May force public health officials to devote inordinate amounts of time and resources to deal with so-called “non-problems.”
Erroneously scare people about potentially useful activities (e.g. cleaning up debris)
Create credibility gaps between engineers and scientists and the decision makers. I
In turn the public loses confidence in public health agencies.

23. Re-habitation Longest potential exposures
Closest to typical metrics (e.g. Lifetime average daily dose)
Conservative approaches are challenged
People and businesses want to get back to normal
Need solid reasons for denying this…
Benchmark?
Something like the “residential standard” from Superfund?
Remediate to a level as if accident never occurred?

24. Restoration Restoring normalcy
Even enhancing to improve resilience to address next “problem” and to prevent future disasters
Resilience in humans is analogous to ecosystem resilience.

25. LCA is another promising tool
Need to use a systems perspective with a holistic approach to broaden the range of impacts included in environmental decision making.
LCA is typically one of the most comprehensive tools, attempting to prevent unknowingly shifting pollutants, damages, and resource uses; but assessments typically don’t quantify disasters. (Areas of Protection paper).
Need to be comprehensive, but data and models are sometimes not available to allow quantitative predictions and there are multiple sources of uncertainty.

26. Quantitative methods can be expanded to include
impact categories of interest to communities
Social Impacts
LOCALLY SITE SPECIFIC
Water Use
Human Health Criteria Pollutants
Global Climate Change
Ozone Depletion
Eutrophication
Human Health
Non Cancer
Smog Formation
Fossil Fuel Use
Acidification
Ecotoxicity
Rare Earth / Mineral Use
Human Health Cancer
SITE SPECIFIC
POPULATION SPECIFIC
Characterization Modeling
Land Use
MORE CERTAIN LESS CERTAIN
Economic Impacts
MORE CONSENSUS LESS CONSENSUS
Employment
Occupational Health
Pathogens
Accidents
How much time and effort should go into developing the individual models that could be included?
Localized Exposures
Landfill Leaching
Figure adapted from: Bare, J. LCA Life Cycle Impact Assessment Webinar -

27. Conclusions
Recent and current disasters indicate that we continue to be surprised and ill-prepared
However, we now have tools and capabilities that are far better than before WTC.
We just need to use them more effectively.

28. Contact me: vallero.daniel@epa.gov