Drycleaner Site Profiles

American Cleaners - Southroads Shopping Center, St. Louis, Missouri

Description
Historical activity that resulted in contamination.

This facility is an active dry cleaners that switched to non-chlorinated solvent in 2007 and is located in a shopping center. A limited subsurface investigation indicated elevated levels of perchloroethylene in soil and groundwater, including cis-1,2-DCE, TCE and vinyl chloride. Subsequent investigations determined significantly elevated levels of perchloroethylene. The main area of contamination was found to be located in the parking lot just beyond the back door of the dry cleaners.

Remediation Status: Site closed


Contaminants
Contaminants present and the highest amount detected in both soil and groundwater.


Contaminant Media Concentration (ppb) Nondetect
cis-1,2-Dichloroethene groundwater
cis-1,2-Dichloroethene soil
methylene chloride soil
Tetrachloroethene (PCE) groundwater
Tetrachloroethene (PCE) soil
Trichloroethene (TCE) groundwater
Trichloroethene (TCE) soil
Vinyl Chloride groundwater
Vinyl Chloride soil

Site Hydrology

Deepest Significant Groundwater Contamination:   18ft bgs
Plume Size:  
Average Depth to Groundwater:   12ft

Lithology and Subsurface Geology

 
  asphalt and gravel base
Depth: 0-1ft bgs
1ft thick
 
  silty clay
Depth: 1-12ft bgs
11ft thick
 
  clay
Depth: 12-18ft bgs
6ft thick
 
  bedrock
Depth: 21ft bgs

Pathways and DNAPL Presence

checkGroundwater
Sediments
checkSoil
checkPresumptive Evidence of DNAPL

Vapor Intrusion Pathway

Has the potential for vapor intrusion (VI) been evaluated?
  Yes
How was the site evaluated?
  Compared sample concentration to screening criteria
Results of VI evaluation:
  A completed VI pathway has been indentified
Has a vapor mitigation system been installed?
  No 

Remediation Scenario

Cleanup Goals:
  Non-residential levels for silty soils. The drinking water pathway was found to be incomplete so the main exposure pathway was the indoor inhalation of vapor emissions from groundwater and soil pathway:
Perchloroethylene: 2.98 mg/l and 3.11 mg/kg
Trichloroethylene: 14.3 mg/l and 15.3 mg/kg
Vinyl chloride: 0.959 mg/l and 0.353 mg/kg
Remedy Level:
  Full Scale Remedy

Technologies

Ex Situ Soil Removal
 

Why the technology was selected:
Soil concentrations in the "hot spot" exceeded site specific target levels developed under a Tier 2 analysis for the indoor inhalation of vapor emissions from subsurface soils pathway. Therefore, the participant and consultant decided to excavate the impacted soils to reduce contaminant levels.

Date implemented:
April 21, 2008 - excavation of impacted soil in the parking lot. A water line leak was also discovered during the excavation and subsequently repaired. This leak is thought to have been the source of the rapid recovery of water levels in nearby monitori

Results to date:
Excavation of approximately 60 cubic yards of impacted soil was completed on April 22, 2008. Subsequent sampling of the groundwater for four quarters showed a significant reduction in the contaminant levels of PCE(2.92 mg/l), TCE (0.56 mg/l), Cis-1,2, DCE (0.555 mg/l) and Vinly chloride (0.034 mg/l). Subsequently, a restrictive covenant limiting the use of the site for non-residential purposes was filed in the property's chain of title and a Certification of Completion letter was issued on June 11, 2009.

Costs

Cost for Assessment:
 
Cost for Operation and Maintenance:
 
Total Costs for Cleanup:
  Environmental Consulting = $22,537.30 Soil Boring/Monitoring Well Installation = $11,731.90 Laboratory Analysis = $7,360.50 Equipment Rental/Lease/Purchase = $1,107.86 Disposal/Treatment = $32,757.58 Groundwater Monitoring = $1,800 Excavation = $10,231.54 Site Restoration = $3,045.40 Other Costs/Permits = $5,415.89 Grand Total = $95,987.97

Lessons Learned







Contacts

Scott Huckstep, Unit Chief
Drycleaning Environmental Response Trust Fund
Missouri Department of Natural Resources

P.O. Box 176
Jefferson City, MO 65102-0176
(573) 526-8913

scott.huckstep@dnr.mo.gov