The objectives of the Department of Toxic Substances Control (DTSC) Supplemental Site Investigation (SSI) Report are to document supplemental site characterization activities and identify data gaps for future work in addition to assessing risk and presenting possible remedial action strategies.

SSI Report Content

Include as applicable:

• Executive Summary – Project objectives, scope of work, main findings.
• Summary of Site Background –
  Location, setting, project contacts, site history.
• Sampling Activities – Soil gas; matrix and groundwater sampling and analysis; locations and rationale; collection and handling.
• Sampling Results and Discussion – Sampling results; discussion of investigations completed; site geology; hydrogeology, fate, and transport; updates to Conceptual Site Model (CSM).
• Risk Evaluation – Exposure pathways and media of concern; evaluations or updates of potential risk to human and ecological receptors; qualitative summary and comparison to screening levels.
• Risk Evaluation – Exposure pathways and media of concern; evaluations or updates of potential risk to human and ecological receptors; qualitative summary and comparison to screening levels.
• Summary, Conclusions and Recommendations – Discuss results and comprehensiveness of site characterization(s) for cleanup or interim actions. Make recommendations for next phase of work, if warranted.