Description
Historical activity that resulted
in contamination.
| W.P. Ballard operated as a wholesale dry-cleaning supply business until 2001. Tetrachloroethylene (PCE) was stored for retail distribution in a 5,000-gallon aboveground storage tank (AST). Approximately 3,500 gallons of PCE were released from the AST in August 1997. Since 2009, the facility has been occupied by US Car Tool, a custom car fabrication business. Remediation Status: In active remediation |
Contaminants
Contaminants present and the highest amount
detected in both soil and groundwater.
| Contaminant |
Media |
Concentration (ppb) |
Nondetect |
| Benzene |
groundwater |
|
|
| chloroform |
groundwater |
|
|
| cis-1,2-Dichloroethene |
groundwater |
|
|
| 1,1-Dichloroethene |
groundwater |
|
|
| Tetrachloroethene (PCE) |
groundwater |
|
|
| Tetrachloroethene (PCE) |
soil |
|
|
| naphthalene |
groundwater |
|
|
| Trichloroethene (TCE) |
groundwater |
|
|
| Trichloroethene (TCE) |
soil |
|
|
| trans-1,2-Dichloroethene |
groundwater |
|
|
| Vinyl Chloride |
groundwater |
|
|
| Vinyl Chloride |
soil |
|
|
Site Hydrology
| Deepest Significant
Groundwater Contamination: |
|
105ft bgs |
| Plume Size: |
|
Plume Length: 1,550ft
Plume Width: 800ft
Plume Thickness: 105ft |
| Average Depth
to Groundwater: |
|
21.32ft |
Lithology and Subsurface Geology
|
|
Interbedded layers of grey, brown, and reddish brown sandy silt, silty sand, silty clay, silt, and clay
Depth: 0-17.5ft bgs
17.5ft thick
Conductivity: 0.2575ft/day
Gradient: 0.029ft/ft
|
|
|
siltstone with some interbedded mudstone, sandstone, and sandy siltstone
Depth: 17.5ft bgs
|
Pathways and DNAPL Presence
 Groundwater
Sediments
Soil
 DNAPL Present
|
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: |
|
A completed VI pathway has been indentified |
Has a vapor mitigation system been installed? |
|
Yes |
Type of Vapor Mitigation System(s): |
|
Sub-slab Depressurization
Soil Vapor Extraction
|
Additional VI Information: |
|
Soil excavation and an SVE system were installed to address VI for on-site building. |
Remediation Scenario
Cleanup
Goals: |
|
The cleanup goals are attainment of acceptable risk levels in on-site indoor air and demonstration of plume stability.
|
Remedy Level: |
|
Interim Action |
Technologies
In Situ Bioremediation |
|
Why the technology was selected:
Removal of accessible impacted soil was determined to be most effective method of source removal and was conducted concurrent with in-situ placement of EZVI.
Ongoing injection activities are underway to reduce source area concentrations and minimize further off-site plume migration utilizing three permeable reactive barriers (PRBs).
Date implemented:
The soil excavation was completed in November 2008 through January 2009 and consisted of removing 1,173.95 tons. The SVE system began operation in August 2010 and was upgraded in February 2012. In April 2011, approximately 675 gallons of IET's injection
Final remediation design:
SVE is expected to continue as an interim action to address VI concerns. Additional groundwater injection is also planned to achieve cleanup goals.
Other technologies used:
Reductive dechlorination by placing emulsified zero valent iron (EZVI) in a soil excavation and injecting a mixture of EZVI, ZVI, kelp, blue green algae, calcium propionate, and sodium sulfite. The injectate mixture and proposed injection process were designed by Innovative Environmental Technologies (IET).
Results to date:
As of March 2012, air sampling had confirmed the reduction of PCE concentrations in indoor air. Additional contaminant mass was also removed during excavation of 1,173.95 tons of impacted soil. Results of the pre and post-injection groundwater sampling suggest that the pilot phase injection activities have successfully reduced contaminant concentrations within the injection area.
Next Steps:
To address VI concerns, the SVE system will continue to run while sampling indoor air on a semi-annual basis. In addition, groundwater sampling will continue on a quarterly basis while implementing full scale injection activities.
Cost to Design and Implement:
$1,303,667 for all technologies
|
In Situ Permeable Reactive Barriers (PRB) |
|
Why the technology was selected:
Ongoing injection activities are underway to reduce source area concentrations and minimize further off-site plume migration utilizing three permeable reactive barriers (PRBs).
Date implemented:
The soil excavation was completed in November 2008 through January 2009 and consisted of removing 1,173.95 tons. The SVE system began operation in August 2010 and was upgraded in February 2012. In April 2011, approximately 675 gallons of IET's injection
Final remediation design:
SVE is expected to continue as an interim action to address VI concerns. Additional groundwater injection is also planned to achieve cleanup goals.
Other technologies used:
Reductive dechlorination by placing emulsified zero valent iron (EZVI) in a soil excavation and injecting a mixture of EZVI, ZVI, kelp, blue green algae, calcium propionate, and sodium sulfite. The injectate mixture and proposed injection process were designed by Innovative Environmental Technologies (IET).
Results to date:
As of March 2012, air sampling had confirmed the reduction of PCE concentrations in indoor air. Additional contaminant mass was also removed during excavation of 1,173.95 tons of impacted soil. Results of the pre and post-injection groundwater sampling suggest that the pilot phase injection activities have successfully reduced contaminant concentrations within the injection area.
Next Steps:
To address VI concerns, the SVE system will continue to run while sampling indoor air on a semi-annual basis. In addition, groundwater sampling will continue on a quarterly basis while implementing full scale injection activities.
Cost to Design and Implement:
$1,303,667 for all technologies
|
In Situ Soil Vapor Extraction |
|
Why the technology was selected:
Soil vapor extraction (SVE) was selected to address impacted soil that could not be removed due to structural considerations while concurrently mitigating vapor intrusion by depressurization. In addition, ongoing injection activities are underway to reduce source area concentrations and minimize further off-site plume migration utilizing three permeable reactive barriers (PRBs).
Date implemented:
The soil excavation was completed in November 2008 through January 2009 and consisted of removing 1,173.95 tons. The SVE system began operation in August 2010 and was upgraded in February 2012. In April 2011, approximately 675 gallons of IET's injection
Final remediation design:
SVE is expected to continue as an interim action to address VI concerns. Additional groundwater injection is also planned to achieve cleanup goals.
Results to date:
As of March 2012, air sampling had confirmed the reduction of PCE concentrations in indoor air. Additional contaminant mass was also removed during excavation of 1,173.95 tons of impacted soil. Results of the pre and post-injection groundwater sampling suggest that the pilot phase injection activities have successfully reduced contaminant concentrations within the injection area.
Next Steps:
To address VI concerns, the SVE system will continue to run while sampling indoor air on a semi-annual basis. In addition, groundwater sampling will continue on a quarterly basis while implementing full scale injection activities.
Cost to Design and Implement:
$1,303,667 for all technologies
|
In Situ Vapor Mitigation |
|
Why the technology was selected:
Soil vapor extraction (SVE) was selected to address impacted soil that could not be removed due to structural considerations while concurrently mitigating vapor intrusion by depressurization.
Date implemented:
The soil excavation was completed in November 2008 through January 2009 and consisted of removing 1,173.95 tons. The SVE system began operation in August 2010 and was upgraded in February 2012. In April 2011, approximately 675 gallons of IET's injection
Final remediation design:
SVE is expected to continue as an interim action to address VI concerns. Additional groundwater injection is also planned to achieve cleanup goals.
Other technologies used:
Reductive dechlorination by placing emulsified zero valent iron (EZVI) in a soil excavation and injecting a mixture of EZVI, ZVI, kelp, blue green algae, calcium propionate, and sodium sulfite. The injectate mixture and proposed injection process were designed by Innovative Environmental Technologies (IET).
Results to date:
As of March 2012, air sampling had confirmed the reduction of PCE concentrations in indoor air. Additional contaminant mass was also removed during excavation of 1,173.95 tons of impacted soil. Results of the pre and post-injection groundwater sampling suggest that the pilot phase injection activities have successfully reduced contaminant concentrations within the injection area.
Next Steps:
To address VI concerns, the SVE system will continue to run while sampling indoor air on a semi-annual basis. In addition, groundwater sampling will continue on a quarterly basis while implementing full scale injection activities.
Cost to Design and Implement:
$1,303,667 for all technologies
|
In Situ Zero Valent Iron |
|
Why the technology was selected:
Removal of accessible impacted soil was determined to be most effective method of source removal and was conducted concurrent with in-situ placement of EZVI.
Date implemented:
The soil excavation was completed in November 2008 through January 2009 and consisted of removing 1,173.95 tons. The SVE system began operation in August 2010 and was upgraded in February 2012. In April 2011, approximately 675 gallons of IET's injection
Final remediation design:
SVE is expected to continue as an interim action to address VI concerns. Additional groundwater injection is also planned to achieve cleanup goals.
Other technologies used:
Reductive dechlorination by placing emulsified zero valent iron (EZVI) in a soil excavation and injecting a mixture of EZVI, ZVI, kelp, blue green algae, calcium propionate, and sodium sulfite. The injectate mixture and proposed injection process were designed by Innovative Environmental Technologies (IET).
Results to date:
As of March 2012, air sampling had confirmed the reduction of PCE concentrations in indoor air. Additional contaminant mass was also removed during excavation of 1,173.95 tons of impacted soil. Results of the pre and post-injection groundwater sampling suggest that the pilot phase injection activities have successfully reduced contaminant concentrations within the injection area.
Next Steps:
To address VI concerns, the SVE system will continue to run while sampling indoor air on a semi-annual basis. In addition, groundwater sampling will continue on a quarterly basis while implementing full scale injection activities.
Cost to Design and Implement:
$1,303,667 for all technologies
|
Ex Situ Soil Removal |
|
Why the technology was selected:
Removal of accessible impacted soil was determined to be most effective method of source removal and was conducted concurrent with in-situ placement of EZVI.
Date implemented:
The soil excavation was completed in November 2008 through January 2009 and consisted of removing 1,173.95 tons. The SVE system began operation in August 2010 and was upgraded in February 2012. In April 2011, approximately 675 gallons of IET's injection
Final remediation design:
SVE is expected to continue as an interim action to address VI concerns. Additional groundwater injection is also planned to achieve cleanup goals.
Results to date:
As of March 2012, air sampling had confirmed the reduction of PCE concentrations in indoor air. Additional contaminant mass was also removed during excavation of 1,173.95 tons of impacted soil. Results of the pre and post-injection groundwater sampling suggest that the pilot phase injection activities have successfully reduced contaminant concentrations within the injection area.
Next Steps:
To address VI concerns, the SVE system will continue to run while sampling indoor air on a semi-annual basis. In addition, groundwater sampling will continue on a quarterly basis while implementing full scale injection activities.
Cost to Design and Implement:
$1,303,667 for all technologies
|
Costs
Cost
for Assessment:
|
|
$768,506 |
Cost
for Operation and Maintenance:
|
|
$52,650 |
Total
Costs for Cleanup:
|
|
On-going |
Lessons Learned
|
Excavation of impacted soil and concurrent installation of SVE piping is successfully addressing VI concerns. IET's injection mixture has also proved effective for groundwater remediation.
|
Contacts
Delonda Alexander, NC DSCA Program, 1646 Mail Service Center, Raleigh, North Carolina 27699-1646, (919) 707-8365, delonda.alexander@ncdenr.gov
|
Site Specific References
4/15/09 Soil Excavation & In Situ Remediation Letter Report, 8/5/11 Annual Groundwater Monitoring Report
|
|
