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Presentation for City of Brisbane. Final Peer Review Findings. November 7, 2005 (Revised May 10, 2006). Presentation Outline. Purpose Project Overview Summary of Findings Background and Regulatory Framework Objectives and Evaluation Criteria Findings Recommendations Discussion.
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Presentation for City of Brisbane Final Peer Review Findings November 7, 2005 (Revised May 10, 2006)
Presentation Outline • Purpose • Project Overview • Summary of Findings • Background and Regulatory Framework • Objectives and Evaluation Criteria • Findings • Recommendations • Discussion
Purpose • Update April 2005 workshop • Supplemental data • Refine findings • Information to date • Update recommendations
Project Overview • Baylands project area • Former Brisbane landfill • Southern Pacific Railroad facility • Phase 1 development • Former Brisbane landfill • Future development phases • Southern Pacific Railroad facility
Site Map Modified from Workshop Presentation to the City of Brisbane, Brisbane Baylands, Subsurface Environmental Conditions by Universal Paragon Corporation and Burns & McDonnell Engineering Company, Inc., November 18, 2003.
Background and Regulatory Framework • Brisbane Landfill • Former municipal landfill (1933-1967) • RWQCB and County of San Mateo Environmental Health Division (County) • Groundwater Operable Unit 1 (OU-1) • Former Southern Pacific Railroad Facility (1914-1960) and Schlage Lock Facility (1926-1999) • California Department of Toxic Substances Control (DTSC) • Groundwater Operable Unit 2 (OU-2) • Former Southern Pacific Railroad Facility (1914-1960) • RWQCB
Objectives and Evaluation Criteria • Objectives • Provide independent technical review • Serve as community advocate • Support the dissemination of project information • Evaluation Criteria • Adequacy of environmental characterization • Appropriateness of remedial action • Protective of public health and environment
Findings – Brisbane Landfill Adequacy of Environmental Characterization • Evaluation adequate • Limits of waste, except for southern boundary • Landfill gas • Groundwater quality • Leachate • Evaluation incomplete • Landfill settlement
Findings – Brisbane Landfill Cont. • Appropriateness of Remedial Action • Final remedial action plan not developed • Primary issues associated with landfill closure • Landfill gas generation and migration • Leachate generation and transport into groundwater and surface water • Settlement of the landfill surface • Proposed concept is appropriate • Lacks sufficient detail
Findings – Brisbane Landfill Cont. Protective of Public Health and Environment • Overall concept appropriate – final evaluations not complete • Final closure plan - not prepared • Final risk assessments - not prepared • Human health • Primary concern • Landfill gas • Ecological • Primary concern • Leachate seeps
Findings – Operable Unit 1 Adequacy of Environmental Characterization • Primary site contaminants • VOC’s, TPH as Bunker C, metals • Soil – Evaluation incomplete • Additional investigation requested by DTSC • Revised RAP in progress • Groundwater – Generally characterized • Clarification needed for: • A-zone aquitard continuity (‘windows’) • B-zone contamination source • Soil Vapor – Evaluation incomplete • Risk Assessments – Evaluation incomplete • Pending final development plan
Stratigraphic Terminology Possible Gap
Findings – Operable Unit 1 Cont. Appropriateness of Remedial Action • Remedial approach • Limited soil excavation at two locations (VOCs) • Continued operation of groundwater treatment system • Add three extraction wells • Add two monitoring wells • Soil cap • Vapor barriers, as needed • Engineering and Institutional Controls • Reduce/eliminate human health exposure
Proposed Remedial Action – OU-1 Commercial Scenario Engineering Control – Restrict Groundwater Use Engineering Control – Outdoor Inhalation Engineering Control – Indoor Inhalation Legend Proposed Area of Soil Removal Proposed Additional GW Monitoring Well Proposed Additional GW Extraction Well Modified from Burns & McDonnell, Revised Groundwater RAP, Operable Unit 1, January 27, 2005.
Findings – Operable Unit 1 Cont. Protective of Public Health and Environment • Evaluation incomplete • Site RAPs not complete • Final development plan pending • Proposed remedial concept – generally acceptable • Human health • Final risk assessment pending • Ecological • Assessment not performed/identified • Final risk assessment recommended
Findings – Operable Unit 2 Adequacy of Environmental Characterization • Primary site contaminants: • TPH as Bunker C, metals, VOCs • Soil and groundwater – adequately characterized • Surface Water - adequately characterized • Soil Vapor – evaluation incomplete • Risk Assessments – evaluation incomplete • Pending final development plan
Findings – Operable Unit 2 Cont. Appropriateness of Remedial Action • Remedial approach (interim) • Soil Cap - 7 to 10 feet clean soil • Leave in-place TPH and metals impacted soils • Limited VOC soil removal (Spring 2006) • Abandon existing north-south drainage channel • Replace with interim drainage channel (Spring 2006) • Engineering and Institutional Controls • Reduce/eliminate human exposure • Not defined/delineated
Findings – Operable Unit 2 Cont. Protective of Public Health and Environment • Evaluation Incomplete • Interim RAP approved by RWQCB • Final Site RAP pending • RWQCB Site Cleanup Order pending • Human health • Proposed remedial concept – generally acceptable • Final risk assessment pending • Evaluate for applicability to current standards • Soil vapor not evaluated • Ecological – acceptable • Proposed concept addresses ecological risk • Based on SFIA values • Evaluate for applicability to current standards • Overall interim concept appropriate – final evaluation not complete
Recommendations • General • Subarea specific • Brisbane landfill • OU-1 • OU-2 • Next steps • Note: not all steps required immediately
Recommendations – General • Financial assurance • Mechanism to manage long-term uncertainties associated with maintenance of streets, utilities, etc • Conceptual site model and remedial action plan • Integrated development-based Baylands plan • Establish evaluation and remedial approach • Develop early in project approval process • Continue evaluation of Baylands environmental documents and plans
Recommendations – Brisbane Landfill • Risk assessment • Final human health assessment • Ecological assessment • Landfill surface settlement evaluation • Settlement studies • Final cover design and construction • Landfill cover • Single, integrated unit • Prevent surface water infiltration and minimize leachate seeps
Recommendations – Brisbane Landfill Cont. • Landfill gas and monitoring • Vapor barriers & methane monitoring • Explosion proof construction – underground utilities • Groundwater monitoring • Post-closure monitoring program • Post-closure monitoring and maintenance plans
Recommendations – Operable Unit 1 • Provide additional information to address: • Soil contamination – type and extent • Groundwater • A-aquitard ‘windows’ • DNAPL source • B-Sand aquifer – VOC source • Consider benefits of in-situ treatment technologies • Source reduction • Augment proposed final remedial approach • Human health and ecological risk • Complete final assessments
Recommendations – Operable Unit 2 • Update soil remedial action plan • VOC soil vapor • Update soil management plan and residual risk management plan • Consider in-situ bioremediation treatment • Source reduction • Augment proposed final remedial approach • Human health and ecological risk • Complete final assessments
Recommendations – Operable Unit 2 Cont. • Prepare monitoring plan for post well abandonment and replacement plan • Assess the brick-lined arch sewer • Structural integrity for proposed tie-in • Evaluate long-term settlement • Final remedial approach consistent with future RWQCB site cleanup order
Recommendations - Next Steps • Develop integrated site conceptual model and development-based Remedial Action Plan • City meet with regulatory agencies to discuss path forward with respect to future requirements • Review revised specific plan and development concept • Evaluate future environmental documents as deemed necessary
Future Studies and Sequencing Future Studies & Program Sequence A Supplemental Data Review B Prior to/concurrent with CEQA C Required by CEQA D Development Plan E Post Development Plan Landfill OU-1 OU-2