Drycleaner Site Profiles

Alpine Cleaners, Portland, Oregon

Description
Historical activity that resulted in contamination.

The former Alpine Drycleaners is located in a mixed commercial-residential zone. Investigations revealed the presence of volatile organic compound (VOC) contamination in the soil and groundwater. The exact set of circumstances leading to the release of perchloroethylene (PCE) to the catch basin is not known. A possible source of the contamination is the alleged disposal of PCE into the storm catch basin between 1987 and 1991. PCE appears to have entered the ground through subsurface breaks in the plastic storm drainpipe immediately adjacent to the drycleaner. This caused local contamination of the soil and introduced PCE and its breakdown products into the shallow groundwater.

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 170 ppb
cis-1,2-Dichloroethene soil 33 ppb
Tetrachloroethene (PCE) groundwater 5,900 ppb
Tetrachloroethene (PCE) soil 12,400 ppb
Trichloroethene (TCE) groundwater 350 ppb
Trichloroethene (TCE) soil 15 ppb
trans-1,2-Dichloroethene groundwater 11 ppb

Site Hydrology

Deepest Significant Groundwater Contamination:   26ft bgs
Plume Size:   Plume Length: 225ft
Plume Width: 120ft
Plume Thickness: 25ft
Average Depth to Groundwater:   12.5ft

Lithology and Subsurface Geology

 
  predominantly clay and silt with widely separated intervals of fine-grained sand
Depth: 0-31.5ft bgs
31.5ft thick
Conductivity: 3.5ft/day
Gradient: 0.021ft/ft

Pathways and DNAPL Presence

checkGroundwater
Sediments
checkSoil
DNAPL Present

Remediation Scenario

Cleanup Goals:
  The Oregon Department of Environmental Quality (DEQ) seeks to remove the contaminant mass from the source area and protect or mitigate threats to human health or the environment. A risk assessment completed in 2003 determined that no significant risk was posed to human health and the environment following completion of SVE/AS. DEQ issued a No Further Action (NFA) determination for the site in January 2004

Technologies

In Situ Air Sparging
 

Why the technology was selected:
Innovative technologies like Hydrogen Release Compound (HRC) were not readily available when the remediation was first conducted at this site. The AS/SVE appeared to be a feasible, cost effective method to reduce concentration levels. Remedy implemented by owner prior to entering Oregon Dry Cleaner Program.

Date implemented:
SVE/AS began in late 1994. System taken off-line in July 2000.

Final remediation design:
The AS system consists of 6 sparging wells screened to a depth of 25-30 ft. bgs., a compressor, piping and associated controls and removes halogenated VOCs from saturated soils and groundwater. All remediation machinery is housed in an on-site concrete slab (6 ft. by 8 ft.) surrounded by a chain-link fence.

Results to date:
Groundwater monitoring and sampling events conducted by contractors indicate that the PCE groundwater plume is stable. Residual VOC concentrations below RBCs for vapor intrusion. The contractor estimated that the remediation system removed approximately 388 lbs. of VOCs during 5 years of operation. The removal of VOCs leveled off after approximately 2 years of operation. A general decrease in groundwater VOC concentrations was observed with the initiation of AS/SVE operation. The most significant change in PCE concentration occurred in the first year: a decrease of PCE from 1200 µg/L to 542 µg/L. Concentrations of PCE breakdown products increased: TCE was sampled at 179 µg/L, cis-1,2-DCE was found at 314 µg/L, and trans-1,2-DCE was found at 22.8 µg/L. Rebounding PCE concentrations, though, were observed in other monitoring well locations.

Next Steps:
DEQ issued No Further Action decision for the site in January 2004 based on the results of the baseline risk assessment that showed that existing contamination did not pose an unacceptable risk to human health and the environment.

Cost to Design and Implement:
Estimated design and implementation costs for AS & SVE were $300K. Much of the work completed prior to entering Oregon Dry Cleaner Program.

In Situ Soil Vapor Extraction
 

Why the technology was selected:
Innovative technologies like Hydrogen Release Compound (HRC) were not readily available when the remediation was first conducted at this site. The AS/SVE appeared to be a feasible, cost effective method to reduce concentration levels. Remedy implemented by owner prior to entering Oregon Dry Cleaner Program.

Date implemented:
SVE/AS began in late 1994. VOC concentrations in SVE system at non-detect by early 1998. System taken off-line in July 2000.

Final remediation design:
Contractors installed horizontal SVE piping installed along the storm drain east of the facility (4-7 ft. bgs) and a four-leg horizontal SVE installed in the trenching for the AS system piping (2-5 ft. bgs.). The SVE operates with a blower pulling a vacuum of 3-6 in. of water on an airflow of 4,500 ft/min. All remediation machinery is housed in an on-site concrete slab (6 ft. by 8 ft.) surrounded by a chain-link fence.

Results to date:
Groundwater monitoring and sampling events conducted by contractors indicate that the PCE groundwater plume is stable. Residual VOC concentrations below RBCs for vapor intrusion. The contractor estimated that the remediation system removed approximately 388 lbs. of VOCs during 5 years of operation. The removal of VOCs leveled off after approximately 2 years of operation. A general decrease in groundwater VOC concentrations was observed with the initiation of AS/SVE operation. The most significant change in PCE concentration occurred in the first year: a decrease of PCE from 1200 µg/L to 542 µg/L. Concentrations of PCE breakdown products increased: TCE was sampled at 179 µg/L, cis-1,2-DCE was found at 314 µg/L, and trans-1,2-DCE was found at 22.8 µg/L. Rebounding PCE concentrations, though, were observed in other monitoring well locations.

Next Steps:
DEQ issued No Further Action decision for the site in January 2004 based on the results of the baseline risk assessment that showed that existing contamination did not pose an unacceptable risk to human health and the environment.

Cost to Design and Implement:
Estimated design and implementation costs for AS & SVE were $300K. Much of the work completed prior to entering Oregon Dry Cleaner Program.

Costs

Cost for Assessment:
  $35,000
Cost for Operation and Maintenance:
  (one year): $6167.00; Electricity for system operation (one year): $2500.00; Quarterly monitoring and sampling (for one year): $3234.00; Quarterly monitoring: lab analysis (one year): $7000.00. Total O&M $40,000.
Total Costs for Cleanup:
 

Lessons Learned

1. Vapor Extraction works well in general, but this site may not have been the best place for it. Contractor noted that given that entire AS/SVE system was installed downgradient of the source area, and that the site subsurface silts are moderately permeable at best, significant influence of SVE at the source area might not be expected. The AS system does not appear to have effectively removed mass from groundwater.
2. Contractor observed significant change in constituent ratios in the source area before and after operation of the downgradient AS/SVE. Contractor has concluded that reductive dechlorination has been occurring in a limited area near the source, that AS/SVE has had little influence over the source area, but did not aerate the areas downgradient of the source area.

Contacts

Bruce Gilles,Project Manager
OR DEQ, Cleanup and Emergency Response
Northwest Region
2020 SW Fourth Avenue, Suite 400
Portland, OR 97201-4987
800-452-4011 or 503-229-6662
gilles.bruce.a@deq.state.or.us

Contractors:
Jack Sparo, Project Manager
AMEC Earth and Environmental, Inc. (formerly AGRA)
7477 S.W. Tech Center Drive
Portland, OR 97223
jspadaro@agraus.com

Site Specific References

DEQ Staff Report, Former Alpine Dry Cleaners Site, ECSI No. 1639, dated November 10, 2003