Volume 6 Issue 2

November 2011


Ecological and Human Health Risk Assessment Provides a Model for Framing and Solving a Wide Variety of Environmental Problems


Risk assessment, commonly identified as a required “step” in the remedial investigations at federal superfund sites, is now commonly employed as part of the decision making process in a wide spectrum of federal regulatory programs, state hazardous materials programs, and scientific applications. This article describes the broad applications where regulators, scientists, and engineers apply risk assessment within the context of characterizing environmental exposures and making decisions regarding the implications of those exposures.

The United States Environmental Protection Agency (EPA) broadly defines risk assessment as “…a process that evaluates the likelihood that adverse ecological effects may occur or are occurring as a result of exposure to one or more stressors.” The important point here is that risk assessment is a process and as such, it has a certain malleability within a structured framework that offers some very specific advantages when applied to environmental problem solving. These specific advantages of risk assessment are that it:

  • offers a widely recognized analytical structure and so facilitates communication among interested parties;
  • is widely used in federal, state, and international programs that offer the user community constantly updated guidance and methods in governmental and Non-Governmental Organizations publications and the peer-reviewed literature;
  • is flexible and therefore can accommodate a wide range of environmental issues;
  • is inherently and explicitly iterative so that users can modify various assumptions in addressing the feasibility of alternative actions;
  • is value added in that once developed, a protocol may be re-applied over several regions, sites, alternatives, or stressors that have similar modes of exposure; and
  • incorporates a detailed conceptual model that encourages broad considerations of potential exposures and pathways, and facilitates input of stake holder’s specific concerns.

Initially, the regulatory requirements of the United States Comprehensive Environmental Response, Compensation, and Liability Act(CERCLA) largely drove the development of risk assessment methods within the United States Environmental Protection Agency (EPA). The EPA continues to be a major source of information and innovation in the development of human health and ecological risk assessment methods (

EPA website

Subsequently a wide variety of federal agencies have developed risk assessment guidance keyed to their particular mission or regulatory environment. The United States Army Corps of Engineers has been particularly active in incorporating risk assessment into the diverse areas of responsibility assigned to them. These activities include the:

Risk-Informed Decision Making
Dr. Todd S. Bridges
Senior Research Scientist, Environmental Science

Other varied applications of risk assessment include:

A US Navy Application

Despite much discussion about the Precautionary Principle in international circles, the international scientific community has taken specific steps to incorporate ecological and human health risk assessment into their approach to environmental problem solving. The International Navigation Association, building on the USACE efforts at guidance development, has published an international standard for risk assessment for dredging and disposal operations in ports and harbors ( The United Nations Food and Agriculture Organization has published a broad review focused on the importance and application of risk analysis to seven major risk sectors of aquaculture production: pathogen risks, food safety and public health risks, ecological (pests) risks, genetic risks, environmental risks, financial risks and social risks. ( The International Union of Pure and Applied Chemistry is currently developing risk assessment guidance for assessing the risks posed by pesticides at agricultural site (

Although ecological and human health risk assessment methods have only developed over the past twenty years, they have found and continue to find broad application in a wide variety of national and international programs. The flexibility, versatility, and mandated transparency of the method makes the general approach applicable to a broad range of environmental problems from site specific issues to using the approach in a comparison of alternatives or technologies.

Submitted By:
Jerome J. Cura, Ph.D.
Senior Environmental Scientist

(Return to Newsletter Main Page)