Drycleaner Site Profiles

Sharon Cleaners #600028, Charlotte, North Carolina

Description
Historical activity that resulted in contamination.

Site is a former perc facility from 1994 to 1998. It is currently used as a pick-up/drop off location only and occupies the ground floor end unit of a 2-story strip shopping center built slab on grade. Investigations conducted to date indicate the release area was located in rear of facility near the sewer line connection.

Remediation Status: In groundwater monitoring


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


Contaminant Media Concentration (ppb) Nondetect
Benzene groundwater
Benzene soil
chloroform groundwater
chloroform soil
cis-1,2-Dichloroethene groundwater
cis-1,2-Dichloroethene soil
1,2-Dichloroethane groundwater
1,2-Dichloroethane soil
1,1-Dichloroethene groundwater
ethylbenzene groundwater
ethylbenzene soil
methylene chloride groundwater
Tetrachloroethene (PCE) groundwater
Tetrachloroethene (PCE) soil
Trichloroethene (TCE) groundwater
Trichloroethene (TCE) soil
toluene groundwater
toluene soil
trans-1,2-Dichloroethene groundwater
trans-1,2-Dichloroethene soil
Vinyl Chloride groundwater

Site Hydrology

Deepest Significant Groundwater Contamination:   75ft bgs
Plume Size:   Plume Length: 1,500ft
Plume Width: 940ft
Plume Thickness: 75ft
Average Depth to Groundwater:   14.3ft

Lithology and Subsurface Geology

 
  clayey silt
Depth: 0-20ft bgs
20ft thick
Conductivity: 0.000224ft/day
Gradient: 0.02ft/ft
 
  silt and sand
Depth: 20-60ft bgs
40ft thick
 
  granite bedrock
Depth: 60ft bgs

Pathways and DNAPL Presence

Groundwater
Sediments
Soil
checkPresumptive Evidence of DNAPL

Vapor Intrusion Pathway

Has the potential for vapor intrusion (VI) been evaluated?
  Yes
How was the site evaluated?
  Soil vapor and/or Sub-slab vapor sampling,Indoor air sampling,Groundwater sampling,Compared sample concentration to screening criteria,Used an exposure screening model
Results of VI evaluation:
  The VI pathway was ruled out (or does not exist)
Has a vapor mitigation system been installed?
  No 
Additional VI Information:
  VI sampling data has been collected at the drycleaning unit, the adjacent commercial units, four downgradient residential properties, and a second on-site building. Based on the sampling results the VI pathway was ruled out.

Remediation Scenario

Cleanup Goals:
  To reduce contaminant concentrations so that the site risks do not exceed a cumulative cancer risk of 1E10-5 and a hazard index below 1.0. Demonstration of plume stability and protection of downgradient surface water body.
Remedy Level:
  Interim Action

Technologies

In Situ Bioremediation
 

Why the technology was selected:
The technology was selected primarily based on low cost compared to other options.

Date implemented:
A pilot test injection of ABC+® was performed in the source area in October 2009 and October 2010.

Final remediation design:
Additional remediation activities have not been determined.

Other technologies used:
Reductive dechlorination by injecting a mixture of Anaerobic Biochem (ABC®) plus Zero Valent Iron (ZVI), collectively described as ABC+®.

Results to date:
The injection was successful in significantly reducing source area contaminant concentrations. Concentrations of PCE reduced by over 99 percent in wells MW-1 and MW-18. Some increases in the concentrations of breakdown products (trichloroethylene, cis-1,2-dichloroethylene, and vinyl chloride) have been observed following injection, but these concentrations are expected to reduce over time due to biological reductive dechlorination.

Next Steps:
Additional groundwater and surface water monitoring is planned. The need for additional remedial activities will be dependent on future sampling data.

Cost to Design and Implement:
$80,740.15

In Situ Zero Valent Iron
 

Why the technology was selected:
The technology was selected primarily based on low cost compared to other options.

Date implemented:
A pilot test injection of ABC+® was performed in the source area in October 2009 and October 2010.

Final remediation design:
Additional remediation activities have not been determined.

Other technologies used:
Reductive dechlorination by injecting a mixture of Anaerobic Biochem (ABC®) plus Zero Valent Iron (ZVI), collectively described as ABC+®.

Results to date:
The injection was successful in significantly reducing source area contaminant concentrations. Concentrations of PCE reduced by over 99 percent in wells MW-1 and MW-18. Some increases in the concentrations of breakdown products (trichloroethylene, cis-1,2-dichloroethylene, and vinyl chloride) have been observed following injection, but these concentrations are expected to reduce over time due to biological reductive dechlorination.

Next Steps:
Additional groundwater and surface water monitoring is planned. The need for additional remedial activities will be dependent on future sampling data.

Cost to Design and Implement:
$80,740.15

Costs

Cost for Assessment:
  $136,286.92
Cost for Operation and Maintenance:
  Not applicable.
Total Costs for Cleanup:
  On-going.

Lessons Learned

MIP and direct-push sampling was performed prior to injection to locate source areas and specifically target injection areas. The targeted injection is considered the key to remediation success at this site. It was also found that in tight soils multiple small injections reduces the potential for day-lighting issues.

Contacts

Al Chapman, L.G, Project Manager
DSCA Program
NCDENR - Division of Waste Managment
1646 Mail Service Center
Raleigh, NC 27699-1646

Phone: (919) 707-8368
Fax: (919) 707-8368
Email: Al.Chapman@ncdenr.gov
Website: www.ncdsca.org

Site Specific References

The site reports are available on the NCDENR document portal system located at https://edm.nc.gov/DENR-Portal/. To access the site reports, enter the DSCA site ID# 600028 in the ID Value field under Property criteria fields window, then click the Search button above the Content window. The list of reports for the site will appear in the Content window below the criteria search fields window. Right-clicking on the Adobe Acrobat symbol next to a report in the list will allow downloading, preview, and other options for that report.