W912DR18R0055_-_Attachment_BS_-App_G1OU6_Summary_of_Subsurface_Soil_Gas_2010.pdf

1 0 03 0 File: 660.22A S.E.

ADMINISTRATIVE RECORD

COVER SHEET

AR File Number ________

File:

1 0 03 1S.E. P

AECOM

8005 Outer Circle Rd., Brooks City-Base, TX 78235 T 210.271.0925 F 210.271.3061

8 January 20 10

Mr. Jack Potosnak (3HSI 13) U.S EPA, Region 3 1650 Arch Street Philadelphia, PA 19 103-2029

Subject: Summary of Subsurface Soil Gas and Indoor Air Data - Operable Unit (OU) 6

Dear Mr. Potosnak, Enclosed is a memorandum summarizing the recent soil gas and indoor air data for the OU 6 area. This data was requested by US EPA during the 8 December 2009 meeting held at your office. The memorandum also presents additional data collection activities that will be conducted in January 2009.

If you have any questions or comments regarding this memorandum, please contact the undersigned at (210) 271-0925.

Sincerely

AECOM

Manish M Joshi, P.E.

Project Manager endl: OU 6 Soil Gas and Indoor Air Memorandum - DSCR cc: Mr. Steven Edlavitch, DSCR Mr. Jim Cutler, VDEQ Mr. John Hill, AFCEE

AECOM

Technical Memorandum Operable Unit (OU) 6 Soil Gas and Indoor Air Data

Defense Supply Center Richmond

This technical memorandum presents a summary of the indoor air and soil gas data collected in and around the buildings in the Operable Unit 6 area at the Defense Supply Center

Richmond (DSCR), Virginia. Figure I shows the locations of the buildings of interest at DSCR

(Buildings 54, 150 and 151). The figure also shows the locations of the existing Vapor

Monitoring Probes (VMPs) located near these buildings.

Building 54 Sampling Results:

Building 54 is located on the eastern edge of the Open Storage Area. This building was constructed in 1992. This building was constructed on approximately 4 feet of fill material and a vapor barrier was installed below the building slab. Volatile Organic Compound (VOC) contaminated groundwater has been detected underneath the northern portion of the building.

Currently, the northern portion of Building 54 is used as a storage area and data processing area.

In August 2008, indoor and outdoor air samples were collected from the northern portion of Building 54 as part of the installation-wide indoor air assessment (Earth Tech, 2008).

Specifically one indoor air sample (Cube 27) and one outdoor air sample were collected over a

24-hour period to evaluate the indoor air quality in the northern portion of the building. The air samples were collected using 3M 3500 passive organic vapor monitor and were analyzed at an off-site laboratory via modified NIOSH 1500/1 501 method. Results of the indoor and outdoor air sampling are presented in Table 1. As seen in Table 1, VOCs in indoor and outdoor air were not detected above the reporting limits.

In Spring 2009, VMP-105 was installed next to Building 54 (above the groundwater contaminant footprint) to evaluate the subsurface soil gas conditions. Sub-slab sampling was not conducted in Building 54 due to the presence of the fill material and the vapor barrier. VMP- 105 consisted of a 6" long stainless steel screen installed approximately 3 feet below ground surface.

Soil gas samples from this VMP could not be collected in April 2009, due to excessive moisture in the VMP and the surrounding subsurface due excessive rainfall prior to the sampling date.

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AECOM

Building 54 Recommendations:

One additional VMP will be installed on the western side of Building 54 (within 2 feet of the building) and one VMP will be installed next to Building 85 (guard shack). Soil gas samples will be collected from the new VMPs and VMP-105 in 6-liter Summa canisters and the samples will be analyzed via Method TO-15 for VOCs. The vapor samples will be collected at a rate of approximately 125 mL/min.

Building 150 and 151 Sampling Results:

Buildings 150 and 151 are located in the Army National Guard (ANG) area. These buildings have been and are currently being used as vehicle maintenance shops by the ANG. A few office/cubicles are located in these buildings. VOC contaminated groundwater has been detected primarily underneath Building 15 1.

In Spring 2009, VMPs were installed around Buildings 150 and 151 to evaluate the potential for indoor air impacts due to the OU 6 groundwater contamination. Five shallow

VMPs were installed around Building 151 (VMPs -97, -99, -101, -107 and -110) while two shallow VMPs (VMP-136 and -137) were installed next to Building 150. Similar to VMP-1 05, each shallow VMP consisted of a 6" long stainless steel screen installed approximately 3 feet below ground surface. Soil gas samples were collected from these VMPs in April 2009 and analyzed for VOCs via Method TO-IS. The results of the TO-IS analyses are presented in Table

2. A soil gas sample from VMP-97 could not be collected due to excessive moisture in the

VMP. As seen from the table, non-detect to low ppbV levels of VOCs were detected in these soil gas samples.

Building 150 and 151 Recommendations

Two sub-slab sampling points will be installed in Building 151 near the office areas. Sub-slab vapor samples from these sampling points will be collected in 6-liter Sumnma canisters and the samples will be analyzed via Method TO-IS for VOCs. The vapor samples will be collected at a rate of approximately 125 mL/min.

Based on the results of the sub-slab sampling points, the need for sub-slab sampling in

Buildings 150 and 153 will be evaluated.

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Table 1 Building 54 Indoor and Outdoor Air Sampling Results

Concentratio (ppbV) i~~~~~z ~~~~Bldg. 54 North Tower/

Outdor Ar Inake/ Bldg. 54-North Tower/ Sampes G-562 and Cube 27 Sample

Analyte CX-4760 ~~~GK-5274 and CX-4774

Formaldehyde 1 3 7.7 Ethyl benzene <30 <30 p-Dichlorobenzene <20 <20 I1,2-Dichloroethane <30 <30 2-Pentanone (MPK) <40 <40 Methyl lsobutyl Ketone <30 <30 Toluene <30 <30 Chlorobenzene <30 <30 Cyclohexanone <30 <30 n-Propyl acetate <30 <30 Pentane <40 <40 Tetrahydrofuran <40 <40 n-Hexane <30 <30 Cyclohexane <30 <30 Cyclohexene <40 <40 n-Butyl Acetate <30 <30 Tetrachloroethylene <20 <20 Xylene <100 <100 m-Dichlorobenzene <55 <55 Ethanol <60 <60 lsopropanol <40 <40 Acetone <40 <40 Chloroform <30 <30 Benzene <10 <10 1,1, 1-Trichloroethane <20 <20 Methylene Chloride <30 <30 I, I-Dichloroethane <30 <30 Methyl Ethyl Ketone <40 <40 1, 1,2-Trichloroethane <30 <30 Trichloroethylene <20 <20 jo-Dichl orobenzene <30 <30 lCumene <30 <30

Notes:

ppbV - parts per billion by volume 3 of 5

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Table 2 Building ISO and 151 Soil Gas Sampling Results

0U6IVNMfP-99 0116-VMP-101 0U6-VMP-107 0U6-VMP-I110 0U6-VMP-136-3 0U6-VMP-137-3 Component Method Units 42314 00 4/3/2009 4/23/2009 4/232009 5/1612009 5/16/2009

TII-Dichlorocthenc TO-15IS V <1.3 <113 <1.3 <1 3 <1 3 <1.3 1,2,4-Tnmethylbenzenc TO. IS vb 0.323J 0 39 J 1 3 <I 14 I 4 1I2-DichlomothaneT 0-IS n5 <1 2 <1.2 <1.2 <1 2 <I 2 <1.2 1,3,5-Tnmethylbcencen TO-I oo5 y <I < I 0 481J <I 4.7 0 571J 1,3-B.tadiene TO-I 1 o5 <2.3 <2 3 <2.3 <2.3 <2.3 <23 I,4-Dichlorobenzen 10.15 0 331J 0,273 I 2 <0 83 1.3 0.91 2-Butnone (MEK) TO-IS5 2 6 4.7 7.5 2 7 64 8.6 2-Hexanone TO-5I b 037J 0 591 0,911 0 391 <1 2 <1 2 4-Ethyltoluene TO-IS15 b <I <I 0351 <I 46 062J 4-Methyl-2-pentaone (MIBK) TO-S ph <1.2 <1 2 0411J <1 2 I II <1 2 Acetone TO-Is ,h 13 J 37 36 2 1 ISO 25 Acetoniteile TO-S p <3 <3 <3 <3 0911i <3 Acrolci TO-IS tpphV <2 2 <2 2 1 7 <2~2 0 741J <22 Actylonitnl TO-IS pphV <2 3 <2.3 <2 3 <2 3 0,61 <2 3 alpha.PtNee TO-IS PPbV <0 9 0 281 I 2 <0 9 t.5 0,92 Beneene TOIS ppbV <I 6 <1 6 14J <1 6 10 4 Carbon disulfide TO-IS ppbV 2,8 3 6 5 5 2,9 5.7 4 5 Chlorobetnene TO-IS 1p~bV <I. I <I I <I I <1.1 <1 I <I I Chiloroethanc TO-1IS ppbV <I 9 071 0.533J <I 9 061 0691J Chlocoforn TO-IS vpbV I <I 0 741 0.37J 0 673J 46 0 591i Chloromelban TO-IS ppbV <2 4 0.651J II i 0691J 121 I 21J ciSM1,2.D,chloroethcne TO-IS ppbV <1,3 <1 3 <1 3 <1.3 0531J <1 3

Cyclohexane TO-I 15ppbV <2,9 <2,9 I 71 <2,9 3.5 <2 9 Dichlorodifluoromethane TO-IS5 ppbV 0471J 0561J 0,463J 0531J 0 51 0,651 Eth..nol TO-IS ppbV 10 I II 75 151i 450 20]J EthJacelte TO-IS pobV <28 <22 4 1 '28 <28 I ) Fithylbenzen TO-IS ppVI 0 441J 0 521 1 2 <1 2 10 3 I

Isopropanol TO-IS ppbV I 1 53 2.5i 1 2 2 61 7 5 5 Isopropylbertne TO-IS PnbV <I < I < I <i 0 93J <I LLmtonene TO-IS oPbV 0361J 0 511 17 0 281J 17 0,96 m- &p-Xylene TO-IS ppbV I151i 53 3 7 0 981i 47 1 0 Methyl methtacrylat TO-Is PpbV 17 22 20 14 2 1 28 Meathyl teet-butyl ether (MTBE) TO-IS ppbV <1 4 <1.4 0 53 1 <1 4 <1,4 <1 4 Methylene chlonde TO-Is ppbV <1 4 <1.4 I 8 <1 4 <I 4 0 493J Naphthalenc TO-IS5 ppbV 0,381 0 53 1 0,481J 0,271J 0653 0,45 n-BuIyI a,~ctt TO-IS ppbV <1.1 <I I 0,321 J I I <I I <I I n-Heptatle TO-I ppbV <I 2 <I 2 1,21J <1 2 2 6 0,733) n-He~can TO-I PPhV <I 4 <1 4 2.6 <1 4 3 I 0.571i n-Nonane TO-IS ppbV 0,87 1 036iJ 21i 0,253 25 0 571 n-Octane TO-IS5 pPbV <II1 <I I I13 <I I 24 0,661J n-Propylb.enzen TO-IS5 pphV <I1 < I < I <I1 2 9 0 3 71 O-Xylene TO-I 15ppbV 0.451j 0511i 1.3 <1 2 is 3 7 TProylenc TO-IS vPbV <2 9 1,21i 8 2 <2 9 25 29 1 Styrene TO-IS5 ppbV 0 781J Ii 1 2 0,611J 1 2 1.3 Tetrachlorochcne (PCE) TO-IS5 pbV <0 74 '074 <0 74 0 591 IS <0 74 Teftrahydrofuraet0 TO-IS b <1,7 <1 7 <1 7 <1,7 IS 2 8 Toluene TO-I ppb 091 4 1I 0 74 1 56 20 traet-I,2-D~chloroethene TO-I r1 b <13 <1,3 <1 3 <I 3 <1 3 <1 3 !Triclorothne= IE) TO-I ppb <03 '0 93 2 3 I 7 2 6 <0,93 Trich ootoontaeTO-IS15 V 09 0 321J <0899 0 28 1 0 251J 0333J lVinytacetat TO-IS15 V 1 6.51j 661 4 11 773 48 IVinyl chlorid TO-IS ppb <2 2 4,5 <2<2< ppbV -pats per billio by volume 3 -esitmated NA -Not Analyzd

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