Drycleaner Site Profiles

Starcrest Professional Drycleaners, Sunrise, Florida

Description
Historical activity that resulted in contamination.

Drycleaning using PCE was conducted at this site from March 1972 until May of 1995. The shopping center in which the drycleaning operation was located was razed in 1999/2000. Under a voluntary cleanup, approximately 20 inches of soil was excavated from beneath the floor slab of the bay that formerly housed the drycleaning operation. The former location of the bay that housed the drycleaning operation is now a parking lot for the new shopping center.

Remediation Status: In groundwater monitoring

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


Contaminant Media Concentration (ppb) Nondetect
cis-1,2-Dichloroethene groundwater 2,640 ppb
cis-1,2-Dichloroethene soil 2,730 ppb
Tetrachloroethene (PCE) groundwater 648 ppb
Tetrachloroethene (PCE) soil 4,600 ppb
Trichloroethene (TCE) groundwater 152 ppb
Trichloroethene (TCE) soil 96.1 ppb
trans-1,2-Dichloroethene groundwater 16.4 ppb
trans-1,2-Dichloroethene soil 409 ppb
Vinyl Chloride groundwater 30.2 ppb
Vinyl Chloride soil 41.4 ppb

Site Hydrology

Deepest Significant Groundwater Contamination:   100ft bgs
Plume Size:   Plume Length: 220ft
Plume Width: 130ft
Plume Thickness: 95ft
Average Depth to Groundwater:   5.43ft

Lithology and Subsurface Geology

 
   fine-grained sand with shells
Depth: 0-3ft bgs
3ft thick
Conductivity: 131.5ft/day
Gradient: 0.00155ft/ft
 
   silty fine-grained sand with organics and shells
Depth: 3-6ft bgs
3ft thick
 
   sandy, weathered limestone
Depth: 6-9ft bgs
3ft thick
 
   silty, fine-grained san
Depth: 9-60ft bgs
51ft thick
 
   fine-grained sand with shell
Depth: 60-68ft bgs
8ft thick
 
   fine-grained sand with limestone lenses
Depth: 68-71ft bgs
3ft thick
 
   dense limestone
Depth: 71-115ft bgs
44ft thick

Pathways and DNAPL Presence

checkGroundwater
Sediments
checkSoil
DNAPL Present

Vapor Intrusion Pathway

Has the potential for vapor intrusion (VI) been evaluated?
   No
Has a vapor mitigation system been installed?
    
Additional VI Information:
  Soil source area at the site was excavated and removed.

Remediation Scenario

Cleanup Goals:
   Groundwater: PCE = 3 µg/L; TCE = 3 µg/L; cis 1,2-DCE = 70 µg/L; trans 1,2-DCE = 100 µg/L; vinyl chloride = 1 µg/L

Soil: PCE = 30 µg/kg; TCE = 30 µg/kg; cis 1,2-DCE = 400 µg/kg; trans 1,2-DCE = 700 µg/kg; vinyl chloride = 7 µg/kg
Remedy Level:
   Interim Action

Technologies

In Situ Bioremediation
  

Why the technology was selected:
Bioremediation was chosen as the groundwater remedy because of the anerobic conditions existing in groundwater and the presence of PCE daughter products (TCE, Cis 1,2-DCE, Trans 1,2-DCE and vinyl chloride).

Date implemented:
July 2005

Results to date:
Contaminated soil was excavated to a depth of 7 ft below the parking lot over an area approximately 45 ft x 50 ft. Approximately 347 cubic yards (434 tons) of contaminated soil was excavated and disposed of offsite. Fifteen gallons of a 60%-purity bulk solution of potassium lactate was poured into the exposed groundwater in the excavation prior to backfilling of the excavation with clean fill. During the lastes monitoring event, conducted in June 2008, No PCE or TCE was detected in groundwater. Four monitor wells produced groundwater samples with contaminant concentrations exceeding MCLs: one well had a Cis 1,2-DCE concentration of 231 ug/l and three wells had vinyl chloride concentrations exceeding the MCL: ranging from 1.7 to 9.5 ug/l.

Next Steps:
Continue monitored natural attenuation.

Cost to Design and Implement:
$55,000 for all technologies
Ex Situ Soil Removal
  

Why the technology was selected:
Excavation was chosen as the soil remedy because of the shallow water table and accessibility (source area was located under a parking lot).

Date implemented:
July 2005

Final remediation design:
During site assessment activities, a modified soil gas survey was conducted. Three vapor extraction wells were installed in 4-ft-deep hand-augererd borings. A 2-HP regenerative blower was used to extract soil gas at a flow rate of approximately 120 cfm, at a vacuum of 40 inches of water. Soil gas was extracted from each point for approximately 30 minutes. A soil gas sample from each extraction point was sent to a fixed laboratory for analysis. The highest contaminant concentration detected in soil gas samples was 46.4 milligrams per cubic meter in a sample collected near what was formerly the service alley behind the drycleaning facility. Conventional soil sampling was used to delineate the extent of soil contamination.

Results to date:
Contaminated soil was excavated to a depth of 7 ft below the parking lot over an area approximately 45 ft x 50 ft. Approximately 347 cubic yards (434 tons) of contaminated soil was excavated and disposed of offsite. Fifteen gallons of a 60%-purity bulk solution of potassium lactate was poured into the exposed groundwater in the excavation prior to backfilling of the excavation with clean fill. During the last monitoring event, conducted in June 2008, No PCE or TCE was detected in groundwater. Four monitor wells produced groundwater samples with contaminant concentrations exceeding MCLs: one well had a Cis 1,2-DCE concentration of 231 ug/l and three wells had vinyl chloride concentrations exceeding the MCL: ranging from 1.7 to 9.5 ug/l.

Next Steps:
Continue monitored natural attenuation.

Cost to Design and Implement:
$55,000 for all technologies

Costs

Cost for Assessment:
   $137,400
Cost for Operation and Maintenance:
   Monitoring: $ 6,500/year
Total Costs for Cleanup:
  

Lessons Learned

1. A modified active soil gas survey is a good tool for locating contaminant source areas at drycleaning sites, particularly at sites where the building that housed the drycleaning operation has been razed and little is known concerning the former locations of equipment, waste storage areas and historical waste disposal areas.

2. Considerable contaminant mass was sorbed onto organic material in the organic-rich sand that occurs at 6-9 ft bgs. Removal of most of this material has resulted in substantial decreases in contaminant concentrations in groundwater at the site.

Contacts

Stacie Davis, Project Manager
Bureau of Waste Cleanup (MS4520)
Florida Department of Environmental Protection
2600 Blair Stone Road
Tallahassee, Florida 32399-2400
Phone: (850) 245-8967
E-mail: Anastasia.Davis@dep.state.fl.us

Contractor:
Steve Folsom, P.E.
H.S.A. Engineers & Scientists
4019 East Fowler Avenue
Tampa, Florida 33617-2008
Phone: (813) 971-3882
E-mail: SFolsom@hsa-env.com

Site Specific References

1. Contamination Assessment Report - December 2005
2. Interim Source Removal Plan - November 2004
3. Interim Source Removal Report - January 2006
4. Groundwater Monitoring Reports 2006 - 2008