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Cleanup in Vulnerable Communities'Initiative Final Project Reference:Bobson Cleaners <br /> Discovery and Enforcement Discovery Project Number:60688620-5.1 <br /> Investigation Work Plan <br /> 8. Discovery Investigation Report Preparation <br /> A DI Report presenting the results of the overall investigation will be prepared. The DI Report will include site <br /> background and environmental setting information,field procedures, presentation of field observations and analytical <br /> results including boring logs and laboratory report sheets, data review results,findings, conclusions and <br /> recommendations, summary tables and sampling maps,the human health vapor intrusion screening evaluation, and <br /> a summary of the public participation activities. <br /> The conclusions of the DI Report will answer three main questions: <br /> • Have current or past practices resulted in a release or threat of a release due to dry-cleaning operations at the <br /> Site? <br /> • If a release due to dry-cleaning operations has occurred, does it pose a significant threat to public health or the <br /> environment, and if not,why not? <br /> • What further specific information and/or removal/remediation actions are necessary in order to better assess or <br /> abate threats posed by the Site to human health and the environment? <br /> AECOM will prepare a draft DI Report to document all sampling activities and present chemical data. In the report, <br /> sampling locations will be labeled on maps with legends and markers that describe the types of media sampled/and <br /> type of sampling performed and represent the concentrations of the chemical compound of concern depicted in the <br /> map(e.g. size of marker representing relative concentration, markers labeled with the concentration of chemical <br /> compound of concern for screening level comparison purposes(both 0.03 and 0.001 attenuation factor values), and <br /> concentration contour lines and suspected source labeled.The initial attenuation factor for soil gas is 0.03, and 0.001 <br /> is the attenuation factor for ground water to indoor/ambient air. Sampling results/data will be analyzed using both 0.03 <br /> and 0.001 attenuation factors, and the results will be summarized in tables that contain current and relevant human <br /> health regional screening levels(as described in DTSC HHRA Notes 3 and 4)for comparison; similar <br /> measurement/metric units will be used to facilitate comparison. <br /> Findings, conclusions, and recommendations will be made regarding the need for further actions to further assess <br /> and/or remediate conditions at the Site, based on site investigative findings and the risk screening evaluations in <br /> order to make planning decisions, or move forward with redevelopment. If further action is recommended, the DI <br /> Report will identify remaining data gaps and/or remediation needs and strategies.The DI Report will also include <br /> recommendations for expedited response actions necessary to mitigate any immediate potential hazards to public <br /> health or the environment, if needed. No-further-action recommendations will be made if the screening level <br /> assessment indicates that cumulative risks/hazards of detected contamination are determined to be below risk-based <br /> screening levels. <br /> Prepared for: Department of Toxic Substances Control AECOM <br /> 31 <br />