Investigation and Remediation of Contaminated Soil and Groundwater from a former Dry Cleaner Site
Risk-Based Decisions, Inc. undertook characterization of the release of contaminants, primarily PCE, from a former dry cleaner located in a strip mall adjacent to a school and residential properties.
A statistically predictive sampling plan revealed PCE in soil gas at:
- several tens of millions of micrograms per cubic meter near the source.
- tens of thousands of micrograms per cubic meter as far as 300 feet away from the former dry cleaner.
Groundwater was at about 60 feet below ground surface and impacted at about 200 ppb PCE.
RBDI reasoned that if the contamination had spread so far laterally within the soil column, the judicious placement and screening of soil vapor extraction (SVE) wells should remove the PCE from the soil. Some SVE wells were screened to see if PCE in groundwater could also be reduced using just the SVE system.
In five years, both soil and the groundwater have been cleaned up to residential standards. Vapor intrusion modeling followed by confirmatory Indoor air testing showed no risks to tenants at the strip mall.
The California Water Boards has issued a No Further Action letter (June 2017) dry cleaning NFA letter.
This is our second successful cleanup of PCE in both soil and groundwater using just a SVE system among many other successful chlorinated solvent site cleanups. Site investigation through regulatory site cleanup was achieved at about 60% of the approved budget.