Phase I Environmental Site Assessment
(Phase I ESA)

 
 

CATEGORY OF SERVICE, LOCATION:

Phase I Environmental Site Assessment (Phase I ESA), East Palo Alto, California

TYPE OF CLIENT:

Land Developer

BACKGROUND:

The site was the location of a former metal plating facility and Trinity was contracted by the property owner to perform a Phase I ESA for the site.  Soil and groundwater were affected with various metals and volatile organic compounds (VOCs), and inside building floors, walls and ceilings were affected with various metals above action levels.  The past and current property owners had previously performed extensive soil and groundwater assessment and limited soil remedial actions to cleanup soil and groundwater impacts and encapsulated metals on building walls, ceiling and floors to prevent metals exposure to future building occupants.  Site investigative and remedial action measures are complete and meet applicable regulatory criteria for no further investigative or remedial action for commercial property use.

CLIENT GOALS FOR PROJECT:

Client goal was to perform an updated ASTM E1527 Standard Practice for Phase I ESA and identify any environmental concerns, investigative and or remedial data gaps or actionable items needing to be conducted to ready the site for commercial occupancy.

PROJECT APPROACH:

  • Complete a Phase I ESA per the ASTM E1527 Standard Practice
  • Perform a comprehensive file review of all previous environmental reports, documents and regulatory correspondence for the site
  • Perform a preliminary risk assessment using existing analytical data
  • Perform a site reconnaissance as part of the Phase I process paying particular attention to areas previously identified in the past as source areas

RESULTS, RESOLUTION, NEXT STEPS:

  • Risk assessment screening indicated that Environmental Screening Levels (ESLs) were exceeded for some chemicals of concern (COCs).
  • A sanitary sewer line on the property was identified for further assessment with a video survey being recommended, followed by soil sampling and laboratory analyses.
  • A sub-slab soil gas survey was recommended within the building to determine if a risk to human health via the soil vapor pathway exits beneath the building.  Sub-slab soil gas results to be compared to health screening levels for commercial workers.
  • The concrete floor in the building was recommended for sealing to isolate future tenants from exposure to impacted concrete materials.
  • A topographically low area in front of the building was noted as a potential recognized environmental condition.  Trinity recommended further assessment in the area via the advancement of one soil boring, collection of soil and grab-groundwater samples, and laboratory analyses for selected COCs.
  • A previously-unknown septic tank consisting of a 55-gallon drum was discovered during site grading.  It was recommended that the area be assessed for site COCs by drilling one soil boring, and collecting soil and grab-groundwater samples for laboratory analysis.
  • The above Phase II investigative actions were performed and results indicated that a sub-slab depressurization system needed to be designed and installed beneath the building concrete foundation to mitigate VOC vapors from potentially entering the building through the concrete slab.
  • A passive soil vapor mitigation system was designed by Trinity, approved by the San Francisco Regional Water Quality Control Board, permitted through the Bay Area Air Quality Management District, and installed.
  • Building upgrades were completed by the property owner and the site was leased to a commercial tenant as desired.

CATEGORY OF SERVICE, LOCATION:

Phase I Environmental Site Assessment (Phase I ESA), Santa Cruz, California

TYPE OF CLIENT:

Commercial Property
Small Business Owner

BACKGROUND:

The site is the location of a retail store selling outdoor and camping goods.  Trinity was contracted by the property owner to perform a Phase I ESA to prepare the property for future sale.  The property is located in an area known for off-site soil and groundwater contamination associated with underground storage tanks in addition to residual soil waste associated with a nearby former coal gasification plant owned by PG&E.

CLIENT GOALS FOR PROJECT:

Client goal was to perform an ASTM E1527 Standard Practice for Phase I ESA with a vapor encroachment screening evaluation to identify any environmental concerns, investigative and or remedial data gaps or actionable items needing to be conducted to ready the site for commercial sale.

PROJECT APPROACH:

  • Complete a Phase I ESA per the ASTM E1527 Standard Practice
  • Perform a comprehensive file review of all previous environmental reports, documents and regulatory correspondence for nearby know contamination sites
  • Perform a site reconnaissance as part of the Phase I ESA process
  • Determine if any recognized environmental conditions or vapor encroachment concerns from neighboring properties exist at the site
  • Make recommendations for Phase II environmental site assessment of soil, groundwater and/or soil gas if necessary
  • Document the findings of the Phase I ESA in a report for a fixed fee contract price and set schedule

RESULTS, RESOLUTION, NEXT STEPS:

  • Trinity completed the Phase I ESA and identified the presence of various recognized environmental conditions
  • Vapor encroachment conditions associated with the property also were identified as a result of previous industrial uses of the property and neighboring properties
  • Based on the age of the building, constructed in the early 1900’s, the buildings construction materials possibly contain lead and asbestos
  • Phase II investigative actions were performed including soiland soil vapor sampling on the property and beneath the building
  • Phase II investigation findings indicated no further action needed with respect to environmental conditions for soil and soil vapor
  • Phase I ESA and Phase II soil and soil vapor investigations were performed on-site and within client approved budgets