Risk assessment is a process that describes and evaluates risk to human health, safety and the environment posed by environmental contamination. Combined with site investigations, risk assessments can be used to identify:

  • Short-term or imminent hazards that may require immediate response;
  • Environmental conditions that could pose an unacceptable risk to humans or the environment if not remediated; and
  • Cleanup standards or “end-points” for remedial planning.

EndPoint uses current science- and toxicology-based methods and procedures to provide human health and environmental risk assessment services that assist our clients in understanding and managing risks associated with environmental contamination. Risk assessment is an evolving scientific approach that can be used to determine acceptable cleanup levels or as an alternative to site remediation.

Many state regulatory authorities have developed simplified approaches to risk assessment that include the use of promulgated numerical cleanup standards for common contaminants detected in certain environmental media. This approach typically requires direct comparison of contaminant concentrations detected at a site to published cleanup standards.  This risk assessment method may be an effective approach to evaluating site risks for relatively small, simple releases of common contaminants. However, since these generic cleanup standards are derived to be conservatively protective of all types of land uses and exposures, they may be “over protective” for some sites, resulting in unnecessary cleanup.

Many state and federal environmental regulations provide different levels of risk assessment so that the complexity of the assessment matches the complexity of the site. For larger, more complex sites, a site-specific risk assessment may be a more suitable approach to assessing site risks instead of simply comparing site data to generic cleanup standards. Site-specific risk assessments allow for the use of specific site information in developing risk-based cleanup levels that are acceptable for a particular site. Site specific risk assessments are typically used when:

  1. The derived cleanup levels are greater than the promulgated numerical cleanup standards;
  2. There are no promulgated cleanup levels for a particular contaminant or for specific environmental media; or
  3. When restrictions or limitations on site activities or uses can be placed on a site to limit exposure, thus allowing more contamination to be left in place.

In addition, some states like Massachusetts allow for a “hybrid” risk assessment approach that allows for modification of some fate and transport model parameters used to develop the numerical cleanup standards. Under this approach, certain site-specific fate and transport parameters may be used to demonstrate that a contaminant concentration which exceeds a promulgated cleanup standard does not pose an unacceptable risk to human health or the environment.

The ability to select the most effective risk assessment method, and produce technically defensible risk assessments is a critical aspect of effectively evaluating and managing risk posed by environmental contamination. The combined effect of:

  1. increasing public interest and involvement in environmental contamination,
  2. further tightening of promulgated numerical standards, and
  3. increased regulatory scrutiny make it more important than ever to produce risk assessments that are based on sound scientific and defensible principles and procedures.