Ecological Risk Assessment

Why is this important? How do we do HHRAs? What assistance is available? Read more about it.

What is it?

An Ecological Risk Assessment (ERA) is the process that evaluates the likelihood that adverse ecological effects are occurring or may occur as the result of exposure to one or more stressors. In CERCLA or RCRA Corrective Action, ERA is used specifically to mean a qualitative and/or quantitative evaluation of the actual or potential impacts of contaminants from hazardous waste sites on plants and animals. Human beings and domesticated animals are not included in this definition. For ecological risk to exist, the contaminant must have the ability to cause an adverse effect and it must co-occur with or contact a plant or animal long enough and at a strong enough intensity to cause the adverse effect.

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Why is this important?

We hold ourselves to a very high standard of protecting the environment, as well as human health. An ERA is an integral portion of the Remedial Investigation (RI) / Feasibility Study (FS) process designed to support risk management decision-making. The RI component of the process characterizes the nature and extent of contamination, and estimates risk to the environment (ecology) posed by contaminants at the site. The FS component develops and evaluates remedial options. Even though the majority of DoD sites are not designated as Superfund sites, ERAs are performed under the US Environmental Protection Agency (EPA) Office of Solid Waste and Emergency Response (OSWER) Ecological Risk Assessment Guidance for Superfund: Process for Designing and Conducting Ecological Risk Assessments.

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How do we do ERAs?

Following the US EPA OSWER Superfund guidance for ERAs, we utilize an eight-step process: (1) Screening-level problem formulation and ecological effects evaluation; (2) Screening-level exposure estimate and risk calculation; (3) Baseline risk assessment problem formulation; (4) Study design and data quality objective process; (5) Field verification of sampling design; (6) Site investigation and analysis phase; (7) Risk characterization; and (8) Risk management.

Step 3 may not be applicable, as Baseline ERAs (BERAs) are not always accomplished; often there is only a site-level ERA. However, the basic steps within Step 3 are examined, e.g., refinement of the preliminary Contaminants of Concern (COCs), literature search for known ecological effects of the species of concern at the site, contaminant fate and transport, the ecosystem(s) potentially at risk, complete exposure pathways, selection of assessment endpoints, refining the conceptual model, and possibly setting the scientific/management decision point (SMDP).

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What assistance is available?

In 1993, the Army formed a group referred to as the Biological Technical Assistance Group (BTAG) to provide technical guidance to Army restoration project managers in the area of ecological risk assessment in response to BTAGs being formed at each of the U.S. EPA Regional Offices, but the Army BTAG was disbanded in 2008. For assistance with specific ERA issues, individuals or installations may contact the Army Institute of Public Health/US Army Public Health Command (AIPH/PHC), U.S. Army Edgewood Chemical & Biological Center (ECBC), the U.S. Army Corps of Engineers (USACE), or the AEC individuals who specialize in risk assessment protocols, ecology, toxicology and natural resources.

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Ecological Risk Assessment