Health & Environmental Risk Assessments in a Perilous World. Risk Uncertainty. Real vs Perceived vs Hidden Risks.

1. Health & Environmental
Risk Assessment
Peter W. Woodman Ph.D.
Risk Management Incorporated
Environmental Services Division
Acton, MA 01720-5676
(978) 266-2878
Copyright 1998-2007 ©
Fifth Annual Environmental Career Night
“Environmental Careers in a Perilous World”

2. 2
Role of Risk Assessors:
Assessment & Communication
 Put your hand over your mouth when you sneeze;
internal organs will be scarce in the post-nuclear
age.
 Try to be neat; fall only in designated piles.
 Drive carefully in "Heavy Fallout" areas; people
could be staggering illegally.
Safety Tips for a Post-Nuclear Existence!!

3. 3
Unforeseen Risks
A woman was killed from chlorine
gas poisoning when she mixed
Harpic™ and Domestos™ together
in a confined space.
She had inadvertently created the
same conditions as experienced by
the soldiers during a gas attack in
the trenches of the First World War

4. 4
Health & Environmental Risks
• Hazardous Chemicals:
Heavy Metals, PCBs, Petroleum Products,
Chlorinated Solvents
• Radionuclides:
U, Th, Pu, Rn, Po
• Biological Agents:
Molds, Bacteria, Viruses
• Genetically Modified Materials:
Animals, Plants, Microorganisms, Pathogens

5. 5
Risk-Impacted Media
• Indoor and Outdoor Air:
Inhalation of vapors, particulates, spores
• Soil and Groundwater:
Incidental/Intentional Ingestion; Dermal
Contact; Inhalation of vapors, particulates, spores
• Surface Water/Environmental Habitats:
Incidental/Intentional Ingestion; Dermal Contact

6. 6
Receptors at Risk
• Human Health:
General Public; Industrial or Commercial
Employees; Residents, Site Trespassers; Site
Workers
• Environmental:
Wildlife, Terrestrial, Aquatic and Benthic Organisms
Habitats of Threatened or Endangered Species

7. 7
Risk Assessment:
Acute, Subchronic, Chronic and Lifetime Exposures
• Human Health:
 Non-Cancer Endpoints of Toxicity
– Hazard Indices
 Cancer Endpoints of Toxicity
– Excess Lifetime Cancer Risks
 Comparison of EPCs to Standards & Criteria
- Air; Drinking Water; Consumption of Fish

8. 8
• Environmental:
 Ecological Screening
- Comparison of EPCs to NAWQC,
Sediment Criteria, Toxicity Thresholds
 Field Studies
- Habitat Assessments, Toxicity Studies
in Indicator Species
Risk Assessment:
Acute, Subchronic, Chronic and Lifetime Exposures

9. 9
Risk Assessment Findings
• Human Health:
 Do Cumulative Non-Cancer Hazard
Indices for Total Site Risk for Each Receptor
Exceed Unity (i.e., HI ≥ 1)?
 Do Cumulative Excess Lifetime Cancer
Risks for Total Site Risk for Each Receptor
Exceed One in a Hundred Thousand
(i.e., 1 x 10-5
)?
 Do EPCs Exceed Applicable Standards or
Criteria?
NO = “NO SIGNIFCANT RISKS”

10. 10
Risk Assessment Findings
• Environmental :
 Any Visible Signs of Apparent Harm?
 Any Impacted Critical Habitats, Vernal Pools,
Threatened or Endangered Species?
 Do EPCs Exceed Applicable Standards or
Criteria for Each Receptor?
 Do Individual Toxicity Quotients for Each
Hazardous Material Exceed Unity?
 Any Positive Toxicity Tests for Indicator
Species?
NO = “NO SIGNIFCANT RISKS”

11. 11
Risk Assessment Challenges
• Assessment :
 Be observant, ask questions, record details
 Work closely with environmental engineers and
hydro geologists to understand and
characterize the nature and extent of the
hazardous contamination
 Identify impacted media and potential receptors

12. 12
Risk Assessment Challenges
• Assessment cont. :
 Determine if exposure pathways either exist or
could potentially exist between the hazard and
the receptor
 Assess risk using site-specific exposure
assumptions and the most current toxicity
information and standards available
 Work closely with your client, state and federal
officials to ensure “No Surprises”

13. 13
Risk Assessment
Challenges
• Communication :
 Clearly describe the Conceptual Site Exposure
Model and assumptions you use to assess the
risks
 Discuss what the risk findings mean for both
current and future foreseeable uses and activities
of the release site

14. 14
Risk Assessment
Challenges
• Communication cont. :
 Ensure that you discuss the uncertainty
and conservative exposure assumptions
associated with the risk findings - nothing
is necessarily black or white!
Finally, become part of the multidisciplinary
team of environmental specialists that assess
these risks and enjoy a common goal – to
protect human health and the environment.