This is one of more than 20 projects Leighton has worked on for Brookfield Residential in Southern California.
The Leighton Solution.
Leighton first investigated this property for the City of Anaheim. During an assessment of a nearby property, Leighton discovered a large area impacted by Perchlorethylene (PCE) as a result of two previous dry-cleaning facilities and possibly other sources.
After thorough assessment of the site limits, it was determined that these offsite properties have impacted groundwater and soil vapor beneath the property with PCE at levels that exceed the California Human Health Screening Levels (CHHSLs) established by the California Department of Toxic Substances Control (DTSC) for residential properties. Using the information from the comprehensive site investigation, a Human Health Risk Assessment (HHRA) indicated that mitigation of PCE in soil vapor would be required to reduce the health risk to acceptable levels in order for the residential development to move forward.
Leighton met with the City, Brookfield Homes, and DTSC to come up with a plan to mitigate the health risk posed by the PCE via the installation of a vapor barrier with passive venting and periodic monitoring of vapor probes. A removal action workplan was approved by DTSC, allowing construction.