Review Sheet #2

Environmental Risk Assessment:
Applications to Hazardous Waste Sites

EV-595 Fall 1997

Readings:


Calculated Risks
Chapter 2 - Exposures- All
Chapter 3 - Into the Body - pp. 25 to 31
Chapter 4 - Assessing Risks - All

Risk Assessment Guidance for Superfund
Chapter 1 - Introduction - All
Chapter 2 - Statutes, Regulations, Guidance and Studies Relevant to Human Health Evaluation - All
Chapter 6 - Exposure Assessment - All

Guidelines for Exposure Assessment (Supplemental Reading)
Federal Register; Vol. 57; No. 104; pp. 22888 - 22938 (May 29, 1992)

Exposure Assessment:

* Definition/Description

- a procedure used to estimate the amount of a substance at an exchange boundary
- a procedure using estimates of magnitude, frequency, duration, and route of exposure to determine dose
- a procedure that examines exposures for past, present, and future
- most interested in present and future

* Three step process - Interrelated





* Step 1 - Characterize the Exposure Setting


- Requires information on:

- Physical Characteristics
- Population Characteristics

- Physical Characteristics - Types

- Climate, Meteorology, Geologic Setting, Vegetation, Soil Type, Hydrogeology, Surface Water

- Physical Characteristics - Sources of Information

- CERCLA documents (PA, SI, RI, FS, EE/CA, Proposed Plan, ROD)
- County Soil Surveys, Wetland Maps (COE), Aerial Photos, Site Visit

- AS COMPILING INFORMATION NEED TO CONSULT WITH OTHER EXPERTS.

- Potentially Exposed Populations - Characteristics

- Location, Activity, Sensitivity (Subpopulations)

- Potentially Exposed Populations - Sources of Information

- Site Visit
- CERCLA documentation
- Other government reports

- Potentially Exposed Populations - Uses

- Current - is happening
- Future - may happen

- Potentially Exposed Populations - Use Categories

- Residential
- Urban
- Rural
- Suburban (?)
- Commercial/Industrial
- Light
- Heavy
- Recreational
- Swimming
- Fishing
- Hunting
- Sports

* CAN HAVE MORE THAN ONE USE AT A SITE *

- Determining Current Use

- % time population in contaminated area
- % time inside and outside
- Seasonal activity patterns
- Special population characteristics
- Sensitivity
- Subsistence
- Activity

- Determining Future Use

- City and County Master Plans
- Bureau of the Census projections
- Other reports that project trends

* FUTURE USE HARD FACTS *

1) Always assume residential use will occur unless there is very strong evidence to support that residential use is not possible.

2) Always consult with the regulatory agencies about any decision regarding future use before starting the risk assessment.

Remember- Residential scenario appropriate at most sites because it provides an upper bound risk estimate that risk managers can use and because it is difficult to prove not possible.

- Sensitive subpopulations

- Need to determine if these are present now or may be present in the future
- Types
- Infants and children
- Nursing mothers
- Pregnant women
- Elderly people
- Infirm (e.g., chronically ill)
- Subsistence farmers or fishers
- Special industrial subtypes (e.g., gardeners, excavation workers)

Last Revised: September 15, 1997

claubergm@mindspring.com -- 15-Sep-1997