STCEnvironmental Services Inc.Environmental Scientists and Engineers

4754 RESEARCH DRIVE

January 28, 2010

Mr. Chris VillarrealProject ManagerU.S. EPARegion 61445 Ross Ave. (6SF-TS)Dallas Texas, 75202

SAN ANTONIO, TEXAS 78240 Office (210) 696-6286 / FAX (210) 696-8761

Subject: Work Plan for Building 1Mitigation of PCE in Indoor AirSaving Square Shopping CenterLeon Valley, Texas

Dear Mr. Villarreal:

Thank you for forwarding the test results for indoor air collected at Building 1 in April 2009 andOctober 2009. Based on the data, we are now prepared to perform additional actions to possiblymitigate and monitor the concentration of perchloroethene (PCE) in indoor air. A discussion ofthe proposed actions for Building 1 is separated into three areas of the building as indicatedbelow.

Area 1 - Cash Advance - 6703 Bandera

The indoor air samples collected at the Cash Advance lease space in October 2009 represent thefirst set of samples showing PCE concentrations below 300 ug/m3. This lease space hashistorically shown the highest levels of PCE. This lease space is also the former location ofRainbow Cleaners, which is the likely source of PCE in indoor air. A summary of selected testresults at Cash Advance and other locations within Building 1 is presented on Table I. A site planshowing the location of the Cash Advance lease space is shown on Figure 1.

We perceive the reduction in PCE at Cash Advance is most likely due to:

1. The installation of two sub-slab depressurization vents installed on the exterior buildingwall in March 2009.

2. The sealing of a sewer penetration in the slab in May 2009.

Based on the data collected in October 2009, we propose that several actions will be performedover the next three years at the Cash Advance lease space. These actions are as follows:

Filename: Work Plan for Building 1 - Final.doc Page 1 of3

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STCEnvironmental Services, Inc.

1. The existing sub-slab depressurization vents will remain operational and be checked forproper operation monthly.

2. One additional indoor air sampling event will be conducted annually. Air sampling will beconducted with Summa canisters and analyzed by Method TO15.

Area 2 - Judge's Office - 6715 Bandera Road

The October 2009 data collected at the Judge's office showed an increase in PCE concentrationswhen compared to the test results collected in January 2009 (See Table I). The Judge's office isone small area within the larger lease space and adjoins the Cash Advance facility. The locationof the Judge's office is shown on Figure 1.

The Judge and Constable vacated the lease space circa September 15, 2009 and this lease spaceremains vacant. The sampling conducted in October 2009 was therefore conducted after the leasespace had been vacant for a period of several weeks. In a vacant lease space, we suspect PCE inair may have had a tendency to accumulate because outside doors were rarely opened and noHVAC system was running. Fans from the HVAC system would most likely circulate anddecrease the concentration, especially in the Judge's office.

The Judge's office immediately abuts the Cash Advance lease space and a spill was documentedat the Cash Advance lease space in October 1997. The Fire Department Incident Report on thisspill noted that liquid, most likely PCE, migrated under the wall of the Cash Advance lease spaceand most likely dissolved carpet mastic in the Judge's office. Given these conditions, it is possiblethat building materials absorbed PCE and solvents could continue to off-gas from these buildingmaterials many years later.

To reduce the potential for a continuing source of PCE in air at the Judge's office, it is proposedthat all sheetrock, carpet, and ceiling tiles will be removed. Studs will not be removed. A sealantor vapor inhibiting sheeting will then be placed on the concrete slab. Sheetrock will then bereplaced on the eastern exterior wall and the southern common wall with the Cash Advance leasespace.

Upon completion of these activities, the indoor air of the Judge's office will be re-sampled using aSumma canister and Method TOI5. The testing will include PCE and other organic compoundsanalyzed by EPA during previous sampling events. A report on the testing will then be providedto EPA. The report will provide the certified laboratory reports, a data validation package, and adiscussion of any additional actions deemed necessary to mitigate or monitor PCE in the area ofthe Judge's office.

Area 3 - Freedom Debt (6709) and the Remainder of the Judge's Lease Space

The current Freedom Debt Lease space (6709 Bandera Road) and the reminder of the lease spaceused by the Precinct Judge and Constable (6715 Bandera) has never shown indoor concentrations

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STCEnvironmental Services, Inc.

ofPCE exceeding 300 ug/m3. Therefore, no further testing or other mitigation efforts are plannedfor these areas. However, because PCE was detected in these areas, existing and future tenantswill be notified.

SUMMARY

Tests in October 2009 show that only the Judge's office in Building 1 contains PCEconcentrations in excess of 300 ug/m3. The removal of building materials and placement of aslab sealant is proposed in the Judge's office to potentially mitigate PCE vapors.

The relatively high concentrations of PCE vapors in the Cash Advance lease space are no longeroccurring. The vents that adjoin the Cash Advance lease space will remain operational and indoorair tests will be collected once per year to monitor conditions.

No monitoring is proposed for the Freedom Debt lease space or areas of the Judge/Constablelease space outside of the Judge's office. All these areas have historically shown that PCE hasnever exceeded 300 ug/m3.

We will await your approval of this wok plan prior to proceeding. If you have any questions,please do not hesitate to contact me at (210) 696-6288.

Respectfully,

C ai Tribley P.G.V· residentCAPM00022

Attachments: Figure 1 - Site Plan of Building 1Table I - Summary of Indoor Air Tests

Filename: Work Plan for Building 1 - Final.doc Page 3 of3

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SAN ANTONIO, TEXAS 78240

Environmental Services Inc. Environmental Scientists and Engineers

4754 RESEARCH DRIVE

N

OFFICE ( 210 ) 696 - 6286 / FAX ( 210 ) 696 - 8761 email: stcenv@attglobal.net

STC SITE PLAN AND INDOOR AIR SAMPLING LOCATIONS - BLDG. 1

Site Plan and Air Sampling Locations - Building 1 - 23595.SKF

FIG. 1

0 10 20 feet

V-102

V-104

V-103

V-101

V-110

V-111

V-112

V-109

CashAdvance

6703

FreedomDebt6709

FreedomDebt6709

Judge'sOffice

Judge and Constable's Lease

Space - 6715Now Vacant Admin

JuvCourt

ExistingVents

Slab Sealed

in Sewer Penetration

Possible PCE spill area on slab - 1997 -

Exact location of spill area unknown

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Table ISummary of PCE Concentrations in Indoor Air

Building 1

Sample ID Date Sample DescriptionPCE in Indoor

Air(ug/m3)

Comments

VI-101-CIA 1/18/2009 Cash Advance - Rear of Lease Space 2400 No mitigation conducted

VI-101-CIA 4/8/2009 Cash Advance - Rear of Lease Space 490 After vent installation but before

sealing of slab penetration

VI-101-CIA 10/9/2009 Cash Advance - Rear of Lease Space 144 After vent installation and sealing

of slab penetrationVI-101-CIADuplicate 10/9/2009 Cash Advance - Rear

of Lease Space 143 After vent installation and sealing of slab penetration

VI-102-CIA 1/18/2009 Cash Advance - Middle of Lease Space 1100 No mitigation conducted

VI-102-CIA 4/8/2009 Cash Advance - Middle of Lease Space 570 After vent installation but before

sealing of slab penetration

VI-103-CIA 1/18/2009 Freedom Debt - western side 150

VI-104-CIA 1/18/2009 Freedom Debt - eastern side 260

VI-104-CIA 4/8/2009 Freedom Debt - eastern side 16

VI-104-CIADuplicate 4/8/2009 Freedom Debt -

eastern side 16

VI-104-CIA 10/9/2009 Freedom Debt - eastern side 59.9

VI-109-CIA 1/18/2009Judge and Constable - Far north end of lease

space84

VI-110-CIA 1/18/2009 Judge's Office 270 No mitigation conducted

VI-110-CIA 10/9/2009 Judge's Office 451After vent installation and sealing

of slab penetration

VI-111-CIA 1/18/2009Judge and Constable - West end - restroom

area130

VI-112-CIA 1/18/2009Judge and Constable - Near center of Lease

space71

VI-117-CIA 10/9/2009 Judge and Constable 31.5 Exact location of sample not yet reported

VI-118-CIA 10/9/2009 Judge and Constable 27.5 Exact location of sample not yet reported

PCE Air Data Summary ‐ Building 1 ‐ PCE Only.xlsSheet1 Page 1 of 1

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