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General

Plant History

RCRA  Corrective Action

Investigation Activities

CERCLA Creek Soil & Sediment Removal Action

Information Evaluation

Risk Assessment

What is Risk?

  • Risk is defined as the probability that a substance or situation will produce harm under specified conditions. Risk is a combination of two factors:
    • The probability that an adverse event will occur
       (such as a specific disease or type of injury); and
    • The consequence of the adverse event.
  • Risk arises from exposure and hazards.

What is Risk Assessment and Risk Management?

  • Risk assessment is the systematic, scientific characterization of potential adverse effects of human or ecological exposures to hazardous agents or activities.
  • Risk management is the process of identifying,   evaluating, selecting, and implementing actions to reduce risks to human health and to ecosystems. The goal of risk management is scientifically sound, cost-effective, integrated actions that reduce or prevent risks while taking into account social, cultural, ethical, political, and legal considerations.
  • Risk management goals should be used to guide risk analyses.
Risk = Exposure x Hazard
 

Exposure Scenarios

  • Where are the contaminants?
  • Who is potentially exposed to the
    contaminants?
  • How might individuals
    encounter contaminants?
  • What are the potential exposure routes?

Health Effects

  • Human carcinogens vs. non-carcinogens
  • What health effects does the chemical cause?
  • Are different effects seen for acute, short-term, and long-term
    exposures?

Dose Estimates

  • The amount of a chemical that enters the body (dose) depends on:
    • Concentration of the
    chemical
    • Intake rate
    • Frequency
    • Duration
  • Decisions on whether to take preventive measures are based on “reasonable maximum exposures”.

Dose-Response Relationship

  • Relationship between the extent of an adverse effect and the amount of a chemical that enters the body.
  • In general, the dose must be high before effects can occur.
  • Severity of effects generally increases with increasingly higher doses.

What are Acceptable Risk Levels?

  • Cumulative site cancer risk of 1 in 10,000 to an individual and noncancer hazard index less than 1, based on Reasonable Maximum Exposure under current and future land use (U.S. EPA 1991).
  • Chemical-specific standards that define acceptable risk levels can be used to determine whether an exposure is associated with an unacceptable risk (U.S. EPA 1991).
  • Background lifetime cancer risk in the United States is
    approximately 4 in 10, or 0.4 (American Cancer Society 1999).