![]() Typically, this is accomplished by comparing a constituent's maximum concentration in surface water, sediment, or soil with an ecological screening value (ESV). ![]() One of the initial tasks of any ERA is to identify constituents that potentially or adversely affect the environment. A more » screening level ecological risk assessments, although abbreviated from a baseline risk assessment, is nonetheless considered a complete risk assessment (EPA, 2001a). The complexity of an ERA ranges from a screening level ERA (SLERA) to a full baseline ERA. Ecological risk assessment is also an essential means for achieving DOE's risk based end state vision for the disposition of nuclear material and waste hazards, the decommissioning of facilities, and the remediation of inactive waste units at SRS. Used to support CERCLA, RCRA, and DOE orders, the ecological risk assessment (ERA) can identify environmental hazards and evaluate remedial action alternatives. One of the principal components of the environmental remediation program at the Savannah River Site (SRS) is the assessment of ecological risk. This assessment indicated that no significant changes in RCRA CAP findings would result from the revisions. ![]() In cases where estimated background concentrations were reduced, site data were reviewed to assess whether significant changes to results of the RCRA CAP findings would result. As a result of these modifications, estimated background concentrations for some metals have been slightly revised from those presented in the original 2002 report. This revision to the 2002 report has been updated to include more rigorous tests of normality, revisions to the statistical methods used for some metals based on the results of the normality tests, and consideration of the depth-dependence of some sample results. The purpose of the 2002 report was to apply the recommended Cal-EPA procedure to the expanded data set for metals that was available at LBNL. This more recent approach differs from that recommended by the USEPA more » and used initially by LBNL (LBNL 2002). In addition, the California Environmental Protection Agency (Cal-EPA) subsequently published a recommended approach for calculating background concentrations of metals at hazardous waste sites and permitted facilities (Cal-EPA 1997). Since that time, many more soil samples were collected and analyzed for metals by the Environmental Restoration Program. These concentration values were estimated using the United States Environmental Protection Agency's (USEPA's) guidance that was available at that time (USEPA 1989). ![]() Local background concentrations of 17 metals were initially estimated by LBNL using data from 498 soil samples collected from borings made during the construction of 71 groundwater monitoring wells (LBNL 1995). Ambient conditions (sometimes referred to as 'local background') are defined as concentrations of metals in the vicinity of a site, but which are unaffected by site-related activities (Cal-EPA 1997). The purpose of the evaluation was to provide a basis for determining if soils at specific locations contained elevated concentrations of metals relative to ambient conditions. As part of its Resource Conservation and Recovery Act (RCRA) Corrective Action Program (CAP), the Lawrence Berkeley National Laboratory (LBNL) Environmental Restoration Program conducted an evaluation of naturally occurring metals in soils at the facility.
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