The conceptual site model (CSM) is defined as "a written description and visual representation of the known, expected, and/or predicted relationships between the site COPCs and the ecological receptors." The CSM depicts the risk assessment team's current knowledge of the site under evaluation. The model identifies:
In the Tier 1 SRA, the CSM is designated as preliminary because it identifies generic assessment endpoints. In contrast, the CSM developed to support the Tier 2 BERA is more detailed and includes identification of measurement endpoints. Figure 2.2 provides an example of a Tier 1 preliminary CSM.
Such a graphical depiction of what is known about your site aids in the identification of complete exposure pathways by providing an easy-to-use template against which each individual COPC identified for your site may be compared and evaluated. The CSM also serves as a very useful communication tool when discussing your site with the regulators or the public. A PC-based software package for constructing CSMs can be found on the Methods and Tools portion of this web site.