Risk Assessment

RiskRisk assessment is the process by which the probability or likelihood of some adverse effect of a contaminant to humans or the environment is estimated. Currently, considerable effort is focused on this topic because assessment of contaminant-associated risk is mandated in key federal laws including the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). Risk assessment is also implied by the phrase "unreasonable risks" in the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) and the Toxic Substance Control Act (TSCA).

Principal investigator: Dr. Michael Newman

In its present form, risk assessment involves 4 steps:

  1. The identification of a potential hazard (e.g., low, but detectable, concentrations of lead in drinking water)
  2. The formulation of a plausible exposure scenario (e.g., human exposure from drinking water)
  3. Identifying some exposure-effect relationship for predicting the level of effect (e.g., epidemiological studies of lead's effect on children exposed through drinking water)
  4. Combining the information from the first 3 steps to estimate the risk of an adverse effect (e.g., less than 1 in 1,000,000 exposed individuals will display an adverse effect as a consequence of the low levels of lead in the drinking water). 
On-going Research
  • Developing predictive models (Quantitative Ion Character-Activity relationships or QICARs) of metal toxicity based on metal ion-ligand binding chemistry
  • Improving current methods of predicting lethal effects by applying survival time methods.
  • Improving methods currently used in ecotoxicology for measuring bioavailability.
  • Risk assessment associated with fish kills and external lesion appearance notionally linked to Pfiesteria or Pfiesteria complex organisms in a selected tributary of the Bay.
  • Evaluation of ambient water and sediment toxicity methods
  • Determining the effect of contaminants in the Elizabeth River estuary on fish population genetics.

MS560 - Fundamentals of Ecotoxicology (SPRING, 3 credit). Prerequisite Basic Ecology. This course is an introduction to ecotoxicology, the science of contaminants in the biosphere and their effects on constituents of the biosphere, including humans. The course provides a general survey of environmental toxicology and risk assessment from an ecological vantage.

MS 640 - Quantitative Ecotoxicology (Spring, 4 credits). A presentation and discussion of essential ecotoxicological principles and quantitative methods for the analysis of ecotoxicological data. Laboratory exercises include method applications with PC-based software. Emphasis is placed on the scientific and statistical soundness of techniques. The materials covered in this course establish the foundation for a second course in environmental risk assessment (MS 641).

MS 641 - Environmental Risk Assessment (Fall, 3 credits). Basic structure and methods for environmental risk assessment are presented for retrospective and predictive assessments. Concepts associated with ecological and human hazard and risk assessments are covered. Discussions of associated logic and methods are framed around the NRC Paradigm of Problem Formulation/Hazard Identification, Effects Characterization, Exposure Characterization, and Risk Characterization.