Drycleaner Site Profiles

Valet Cleaners, Milwaulie, Oregon

Description
Historical activity that resulted in contamination.

The Site is located in a strip mall at 15020 SE McLoughlin Boulevard (Oregon Highway 99E). The vicinity of the Site generally consists of mixed commercial and retail businesses along McLoughlin Boulevard, transitioning to mixed-density residential housing within one block of the highway. The topography of the Site vicinity slopes downward to the southwest (toward the Willamette River ~0.75 miles west). The Site is covered with buildings and pavement (roadways and parking lots), except for some landscaped areas along the highway edge of the property. The Site building is approximately 250 feet long and 80 feet wide (oriented parallel to McLoughlin Boulevard). The building includes four separate tenant spaces, with Valet Cleaners occupying the northernmost space. The other tenant spaces are retail shops, including bicycle sales and service, auto parts sales and distribution, and pet supplies. A basement space is located under a portion of the Auto Parts tenant space that includes two sumps that pump collected water into the sanitary sewer.

Remediation Status: In groundwater monitoring


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


Contaminant Media Concentration (ppb) Nondetect
Tetrachloroethene (PCE) groundwater 700 ppb
Tetrachloroethene (PCE) soil 100 ppb
Tetrachloroethene (PCE) groundwater 700 ppb
Tetrachloroethene (PCE) soil 100 ppb

Site Hydrology

Deepest Significant Groundwater Contamination:  
Plume Size:  
Average Depth to Groundwater:   ft

Lithology and Subsurface Geology

Pathways and DNAPL Presence

checkGroundwater
Sediments
checkSoil
DNAPL Present

Remediation Scenario

Cleanup Goals:
  DEQ RBCs for indoor air-occupational exposure setting 47 ug/m3 for PCE. 3 ug/m3 for TCE.
Remedy Level:
  Interim Action

Technologies

In Situ Bioremediation
 

Why the technology was selected:
Although groundwater concentrations were not highly elevated, it was thought that the shallow water table (~2 feet at times) and basement seeps were the source of elevated indoor air levels.

Date implemented:
2013

Date completed:
2013

Final remediation design:
Groundwater treatment pilot injections were performed on January 28 and 29, 2013. The injections included using push-probe equipment to deliver the selected remediation material (EHC-L, developed by FMC) into the subsurface at several depths (some material was also introduced into the vapor pit screen within the dry cleaners space). A total of 495 gallons of the EHC-L material was injected between four separate locations at a dilution of about 25 to 1. The four injection locations included:
" One angled direct-push boring completed outside on the west side of the building (this point was added to the injection scope to allow injection to depths below 15 feet bgs the maximum depth attainable with the limited-access drilling equipment used for the interior probes). To minimize the distance between the injection point and the target treatment area, the exterior probe was angled toward MW-9, at 20 degrees from vertical. The deep probe was completed to a depth of about 22 feet bgs.
" Two direct-push borings completed within a 5-foot radius of MW-9. The attainable probe depths were 13 and 16 feet bgs.
" The previously installed screen of the Valet Cleaners vapor collection pit (a depth of 5 feet bgs).

For each of the drilled injections, the process included pushing to the maximum depth and retracting the rod four feet to expose the injection screen. The diluted material was injected using a progressive cavity pump and injection pressures for the deep (angled) probe averaged 80 psi while injection pressures for the interior probes were kept low (averaging 25 psi) in order to prevent rapid surfacing of the reagent. A total of
9,400 gallons of solution (376 gallons of EHC-L) were injected at the 18- to 22-foot bgs interval. The tighter soils encountered in the 12- to 15-foot interval resulted in a lower injection volume, with a total of about
2,700 gallons of solution (108 gallons of EHC-L). To prevent the surfacing of the material during application into the vapor-pit screen, the shallow injection was only gravity fed (unpressurized) and only 275 gallons of solution (11 gallons of EHC-L) were applied at the 5-foot depth over the two-day injection period.

Results to date:
Minimal changes have been observed in groundwater concentrations in the year since the pilot test.

Next Steps:
Bi-annual monitoring

Cost to Design and Implement:
$15,000

In Situ Vapor Mitigation
 

Why the technology was selected:
Source area has not been identified.

Date implemented:
2011

Date completed:
2013

Final remediation design:
The scope of work of the IRAM included:
" Installation of sub-slab vapor collection pits and associated system components (piping and fan) to create a relatively low pressure condition beneath the floor slab in the area of the highest sub-slab vapor concentrations to reduce the potential for migration through the floor into the ambient air space above;
" Modification of the existing HVAC systems to increase fresh air intake and interior air pressure to induce positive pressure conditions in the building relative to the sub-slab (to further reduce the potential for vapor intrusion);
" Sealing of the basement sumps and wall seeps to reduce volatilization into the basement airspace, and connection of the sealed air spaces to the vapor collection system (using a historical ventilation duct as a conduit) to further reduce the potential for vapor migration into the basement;

Results to date:
Highly elevated soil gas concentrations remain, but indoor air levels, with the exception of TCE in one tenant space, meet cleanup goals.

Next Steps:
bi-annual monitoring

Cost to Design and Implement:
$40,000

In Situ Bioremediation
 

Why the technology was selected:
Although groundwater concentrations were not highly elevated, it was thought that the shallow water table (~2 feet at times) and basement seeps were the source of elevated indoor air levels.

Date implemented:
2013

Date completed:
2013

Final remediation design:
Groundwater treatment pilot injections were performed on January 28 and 29, 2013. The injections included using push-probe equipment to deliver the selected remediation material (EHC-L, developed by FMC) into the subsurface at several depths (some material was also introduced into the vapor pit screen within the dry cleaners space). A total of 495 gallons of the EHC-L material was injected between four separate locations at a dilution of about 25 to 1. The four injection locations included:
" One angled direct-push boring completed outside on the west side of the building (this point was added to the injection scope to allow injection to depths below 15 feet bgs the maximum depth attainable with the limited-access drilling equipment used for the interior probes). To minimize the distance between the injection point and the target treatment area, the exterior probe was angled toward MW-9, at 20 degrees from vertical. The deep probe was completed to a depth of about 22 feet bgs.
" Two direct-push borings completed within a 5-foot radius of MW-9. The attainable probe depths were 13 and 16 feet bgs.
" The previously installed screen of the Valet Cleaners vapor collection pit (a depth of 5 feet bgs).

For each of the drilled injections, the process included pushing to the maximum depth and retracting the rod four feet to expose the injection screen. The diluted material was injected using a progressive cavity pump and injection pressures for the deep (angled) probe averaged 80 psi while injection pressures for the interior probes were kept low (averaging 25 psi) in order to prevent rapid surfacing of the reagent. A total of
9,400 gallons of solution (376 gallons of EHC-L) were injected at the 18- to 22-foot bgs interval. The tighter soils encountered in the 12- to 15-foot interval resulted in a lower injection volume, with a total of about
2,700 gallons of solution (108 gallons of EHC-L). To prevent the surfacing of the material during application into the vapor-pit screen, the shallow injection was only gravity fed (unpressurized) and only 275 gallons of solution (11 gallons of EHC-L) were applied at the 5-foot depth over the two-day injection period.

Results to date:
Minimal changes have been observed in groundwater concentrations in the year since the pilot test.

Next Steps:
Bi-annual monitoring

Cost to Design and Implement:
$15,000

In Situ Vapor Mitigation
 

Why the technology was selected:
Source area has not been identified.

Date implemented:
2011

Date completed:
2013

Final remediation design:
The scope of work of the IRAM included:
" Installation of sub-slab vapor collection pits and associated system components (piping and fan) to create a relatively low pressure condition beneath the floor slab in the area of the highest sub-slab vapor concentrations to reduce the potential for migration through the floor into the ambient air space above;
" Modification of the existing HVAC systems to increase fresh air intake and interior air pressure to induce positive pressure conditions in the building relative to the sub-slab (to further reduce the potential for vapor intrusion);
" Sealing of the basement sumps and wall seeps to reduce volatilization into the basement airspace, and connection of the sealed air spaces to the vapor collection system (using a historical ventilation duct as a conduit) to further reduce the potential for vapor migration into the basement;

Results to date:
Highly elevated soil gas concentrations remain, but indoor air levels, with the exception of TCE in one tenant space, meet cleanup goals.

Next Steps:
bi-annual monitoring

Cost to Design and Implement:
$40,000

Costs

Cost for Assessment:
  $25,000
Cost for Operation and Maintenance:
  $12,500
Total Costs for Cleanup:
  245,000

Lessons Learned

Shallow groundwater, even at moderate levels (300-400 ppb PCE) below RBCs for volatilization to indoor air, can have a significant impact on indoor air when close to the building floor, or exposed in the basement area. Shallow groundwater levels affect vapor collection system during the rainy season.

Contacts

Mark Pugh
Oregon DEQ
pugh.mark@deq.state.or.us
503 229-5587

Site Specific References

Ash Creek, 2012. Supplemental Interim Remedial Action Measure Work Plan Valet Cleaners, Milwaukie, Oregon. September 25, 2012.

Ash Creek, 2011a. Supplemental Site Investigation Work Plan Valet Cleaners, Milwaukie, Oregon.
August 23, 2011.
Ash Creek, 2011b. Interim Remedial Action Measure Implementation Valet Cleaners, Milwaukie, Oregon.
June 14, 2011.
Ash Creek, 2011c. Interim Action Technology Screening Valet Cleaners, Milwaukie, Oregon. February 7,
2011.

Ash Creek, 2010. Site Investigation Data Summary Report, Valet Cleaners, Milwaukie, Oregon.
December 8, 2010.