Site-specific screening

Brady et al. (2003) proposed that a site-specific screening approach followed by sequential extraction measurements could be an appropriate method to determine if a contaminated site is suited for MNA. In the first step, the site s chemical and hydrological conditions are assessed from standard site characterization data. The MNAtoolbox (www.sandia.gov/eesector/gs/gc/na/mnahome.html) provides a rapid initial assessment of the chemical and hydrologic conditions for MNA. The site-specific assessment for natural attenuation is then evaluated using sequential extraction experiments that enhance the site s characterization, determine the hioavailability, fate, and transport of the metal(loid)(s) in question, and assess natural attenuation against other remediation options (such as phytoremediation). 

Consequence Screening Based Upon Site-specific Conditions (Section 3.3.2) identification of Evaluation-case Events... 

Consequence Screening by Modeling Site-Specific Conditions 35... 

Perform consequence screening by modeling site-specific conditions. 

Site-specific consequence screening for explosion can be performed either qualitatively or quantitatively, depending upon the explosion potential of the materials being handled, as well as processing conditions and other site-specific factors. In performing a consequence screening, it is necessary to select "Evaluation-case" events for consideration. This is defined as follows ... 

Qualitative Consequence Screening Based on Site-Specific Conditions... 

Most of the screening tools and assessment methods discussed in this book rely upon estimates of event consequences, event frequencies, or both. These estimates, in turn, are based upon interpretations of site-specific conditions as well as a determination of which events (of many possible events) are to be considered evaluation-case events. Each step in the evaluation process has the potential to introduce uncertainty into the overall building assessment. As discussed in Reference 87 ... 

Tables I and II present the results of the Work Group discussions for the screening and site-specific level models, respectively. The assessment in these tables is based on a ranking scale between 0 and 100 0 indicates situations where no testing has been attempted and 100 identifies areas where extensive testing has been completed with sufficient post-audits to validate the predictive capability of relevant models. The scores can also be interpreted to mean the extent to which additional field testing would improve our understanding of how well the models represent natural systems. It is important to note that the scores do not indicate model accuracy per se they show the degree to which current field testing has been able to identify or estimate model accuracy.

ATSDR s specific responsibilities related to blood lead screening at lead-contaminated hazardous waste sites include (1) evaluation of site-specific environmental lead exposure information, (2) identification of populations potentially exposed to lead, (3) decision about whether or not to conduct blood lead screening, (4) evaluation of blood lead screening results, and (5) determination of whether the U.S. Environmental Protection Agency s (EPA) proposed site remediation plans are sufficient to protect public health. 

The ecological risk module allows users to perform benchmark screenings for surface water, sediment, soil, and biota. Accompanying the ecological risk module is a database of benchmarks and other information that are supported and updated on the SADA web site. Benchmarks are adjusted for site-specific physical parameters as appropriate. 

NCRP, Recommended Screening Limits for Contaminated Surface Soil and Review of Factors Relevant to Site-Specific Studies, Report 129, National Council on Radiation Protection and Measurements, Bethesda, MD, 1999. 

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