Data Quality Objectives For CERCLA Investigative Process: A Ground Water Case Study. R. Horner, E. Wang, A. Suetter, S. Gross, and R. Sturm, Ogden Environmental and Energy Services, Inc. 221 Main Street, Suite 1400, San Francisco, CA 94105
EPA has developed and implemented a mandatory Agencywide program of quality assurance for environmental data, including a process for developing Data Quality Objectives (DQO). Case studies previously presented by EPA focuses on the development of DQOs for the tailend of remedial investigations (RI) at Superfund sites with surface or near surface soil impacts in a single, limited exposure area. This paper focuses on the development of DQOs for a complex abbreviated RI of the regional groundwater system underlying a site with multiple point sources of potential groundwater contamination. The abbreviated RI combines all stages of the CERCLA investigative process from the site investigation (SI) to the RI. Previous environmental data are not available. Instead, environmental data from concurrent subsurface soil investigations at each point source are combined with regional groundwater data to delineate spatial and temporal dimensions of each point source. An expedited risk assessment approach is then used to rapidly prioritize each point source according to their contribution to human health and ecological risks (relative to other point sources). The purpose of this expedited risk assessment is to streamline the CERCLA investigative process by eliminating as many point sources as possible from consideration as early as possible--either by showing risks are insignificant (relative to other sources) or through removal actions. DQOs for this abbreviated RI are continually evaluated as additional data becomes available, and address the quality and quantity of the subsurface soil and regional groundwater data needed to: maximize comparability between the different subsurface soil investigations, assess the nature and extent of subsurface and groundwater impacts, support the expedited risk assessment, preliminarily assess potential removal options, and preliminarily develop riskbased cleanup goals.