PARENT SESSION
PW11 - Site-Specific Risk Assessments
Wednesday, 20 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P853) Considerations for Developing and Using Ecological Preliminary Remediation Goals (PRGs) .
Lavoie, Daniel1, Petron, Stephen*,2, Corl, W3, Reisch, Timothy3, 1 CH2M HILL, Dayton, OH, USA2 CH2M HILL, Boston, MA, USA3 Atlantic Division, Naval Facilities Engineering Command, Norfolk, VA, USA
ABSTRACT- Preliminary remediation goals (PRGs) are media-specific contaminant concentrations that are the starting point for ecological cleanup goals and are the risk assessors primary input to risk management. PRG development logically follows the identification of complete exposure routes and subsequent risk identified in an ecological risk assessment (ERA). The objectives of this presentation are (1) to discuss numerous considerations influencing PRG development and (2) discuss the usefulness of PRGs in an effective remediation process. There are currently no universally accepted methods for developing ecologically based PRGs. PRGs should be set at levels that would be protective of ecological endpoints, should the site undergo remediation without additional assessment of ecological risk. While published screening benchmarks (i.e., no effect levels) seem a logical starting point for PRG development, they could be overly protective if used as remediation goals. One should consider using lowest effect levels, or similar such endpoints in the initial setting of PRGs. The process of updating PRGs to be more site-specific should rely on strategic and up-to-date chemical/biological data from site-specific laboratory/field investigations (e.g., chemistry, bioassays, biological surveys). Current, site-specific COC and biological effects data are necessary for (1) pinpointing the primary ecological resource to protect (e.g., benthic macroinvertebrate populations), (2) determining which COCs require PRG development (i.e., risk drivers) and (3) deciding how PRGs should be modified to represent site-specific protective levels. The development of ecological cleanup goals should be more than the simple extension of PRGs, but rather should address the protection of ecological endpoints through consideration of all the nine NCP criteria. Use of PRGs as cleanup goals could result in overremediation and should be avoided. Overremediation in habitats that have legal, or otherwise high value, would be in conflict with the avoid, minimize, mitigate paradigm that must be adhered to for these types of trust resources.
Key words: PRGs, sediment, ERAs