Sub-Slab Sampling and Analysis to Support Assessment of Vapor Intrusion at the Raymark Superfund Site

Sub-Slab Sampling and Analysis to Support Assessment of Vapor Intrusion at the Raymark Superfund Site Dominic DiGiulio Office of Research and Development National Risk Management Research Laboratory Ada, Oklahoma March 15, 2004

N Sub-Slab Sampling Locations Near the Raymark Superfund Site (15 house, 1 business) NF Raymark Facility Site HOUSATONIC RIVER Generalized Groundwater Flow Direction 400 0 400 Feet

N Geologic Cross-Sections NF Raymark Facility Site G H H G HOUSATONIC RIVER 400 0 400 Feet

WEST CONTRACT PLATING OU1 FORMER RAYMARK FACILITY Cross-Section G-G EAST ELEVATION (NGVD 1929) 100 80 60 40 20 0-20 -40-60 -80-100 -120 MW-303 (B) FILL 9.14 EOB AT - 22.7 FILL SAND. BARNUM AVE Fill Peat Till RR TRACK SAND Organic silt Clay Silt Sand Bedrock Gravel FILL FORMER TILO IND / STRATFORD SQ. SHOPPING CENTER FILL SAND MW-209 (S,D,B) INTERSECTION OF A-A 6.5 5.45.5 EOB AT - 88.74 GRAPHIC SCALE FILL SAND MW-210 (NEW S,D) ON RAMP TO I 95 SOUTH EOB AT - 29.62 FILL I - 95 SAND EOB AT - 73.47 0 20 0 200 VERTICAL MW-212 (S,M,D,B) INTERSECTION OF B-B FILL 3.33.4 3.53.53.53.5 3.3 3.3 3.3 HORIZONTAL EOB AT - 100 4.6 RESIDENTIAL PROPERTIES (NO TOPO COVERAGE) SAND MW-214 (S,M,D) EOB AT - 35.95 POSS. TILL SHOREL INE HOUSATONI C RIVER Well Screen and corresponding groundwater elevation End of boring with corresponding elevation 100 80 60 40 20 0-20 -40-60 -80-100 -120 ELEVATION (NGVD 1929)

Primary Investigators in Raymark Study Dom DiGiulio U.S. EPA, ORD, NRMRL, Ada, OK Cindy Paul, U.S. EPA, ORD, NRMRL, Ada, OK Ron Mosley, U.S. EPA, ORD, NRMRL, RTP,NC Ray Cody, U.S. EPA New England Regional Office, Boston, MA Scott Clifford, U.S. EPA New England Regional Lab, North Chelmsford, MA Peter Kahn, U.S. EPA New England Regional Lab, North Chelmsford, MA Annette Lee, XDD Ltd. Kaneen Christensen, formerly of XDD Ltd.

Objectives and Status of Research at the Raymark Site in Stratford, CT Evaluate bias associated with commonly used ground-water sampling techniques for VOCs (Cindy Paul- ORD/NRMRL) Discrete Multi-Level Sampling (DMLS) System Sample cell Viton spacer

Ground-Water Profile at Monitoring Well 214S Using Discrete Multi-Level Sampling (DMLS) System Ground-Water Concentration (ug/l) 140 120 100 80 60 40 Specific Conductance (us/cm) Ground-Water Concentration (ug/l) 600 500 400 300 200 100 0 2 3 4 5 6 7 8 9 7 6 5 4 3 2 1 0 water table water table 4 5 6 7 MW-214 TCE (Q4, Q5 screening level = 5 ug/l) 1,1-DCE (Q4, Q5 screening level = 200, 280 ug/l) 1,1,1-TCA (Q4, Q5 screening level = 3300, 4700 ug/l) well sample = 55 ug/l well sample = 32 ug/l well sample = 21 ug/l 20 water table 1,1-DCE (ND) TCE = 0.6 ug/l 1,1-DCE=1.4 ug/l TCE = 2.2 ug/l 0 2 3 4 5 6 7 8 9 Depth (m)

Objectives and Status of Research at the Raymark Site in Stratford, CT Evaluate bias associated with commonly used soilgas sampling techniques (Dom DiGiulio - ORD/NRMRL)

Objectives and Status of Research at the Raymark Site: Develop a sub-slab gas permeability testing protocol support sub-slab depressurization system design (ORD/NRMRL - Dom DiGiulio)

Objectives and Status of Research at the Raymark Site in Stratford, CT Develop a sub-slab sampling protocol and supporting data interpretation methods (Dom DiGiulio - ORD/NRMRL)

56 Objectives and Status of Research at the Raymark Site 72 Evaluate groundwater to indoor air and soil-gas to indoor air attenuation factors (Cindy Paul and Dom DiGiulio - ORD/NRMRL) 53 35 38 11 36 37 2 MW213 0 73 83 MW-214 66 95 100 feet 8 23 113 3 MW523 76 86 96 51 106 125 515 10 50 509 116 9 44 118 123 112 501 45 105 508 49 489 109 46 498 115 48 481 72 492 47 471 125 117 462 472 105 575 MW-526 605 121 520 124 52 550 560 6 71 122 580 600 N Soil-gas and ground-water research area Indoor air and sub-slab sampling Indoor air sample Monitoring well North Housatonic Soil-gas sample (slam-bar) Soil-gas sample (Geoprobe) Ground-water and/or soil-gas sample (Geoprobe)

Conservativeness of Constrained Version of the J&E Model (Q5) at Houses on North Housatonic Soil-Gas Ratios at North Housatonic 1.0E+02 1,1,1-TCA 1,1-DCE TCE Actual/Q5(2.0E-03) 1.0E+01 1.0E+00 1.0E-01

Primary Objectives of Sub-Slab Study Develop a protocol for sub-slab vapor probe installation Develop an algorithm to assess sources of indoor air contamination using: - indoor air data - outdoor air - sub-slab gas, and - soil-gas and/or ground-water data

Typical House at Stratford, Ct

Pre-Sampling Survey

Collecting an Outdoor Sample

Indoor Air Sampling: Collection of a Duplicate Sample

Locating Utilities: Sewer Line Exiting Under the Slab

General Schematic for Installation of Sub-Slab Vapor Probes Concrete Slab Recessed Threaded Cap Cement Grout Brass or Stainless Steel Threaded Fitting or Compression Fitting Brass or Stainless Steel Tubing Sub-slab soil

Drilling a Small Diameter Hole Through A Slab

Inner and Outer Holes

Applying Cement

Probe Used at the Raymark Site

Sources and Significance of Systematic Error: Probe construction materials as a source of VOCs Methanol Extraction of Brass Fittings and Cement Grout for Background VOCs

Sources and Significance of Systematic Error: Probe construction materials as a source of VOCs Use of a Field Probe Blank at the Raymark Site to Ensure that Probe not a Source of VOCs COMPOUND AMBIENT AIR SAMPLING PROBE FIELD BLANK Canister #6582 Canister #6581 (ppb/v) (ug/m3) (ppb/v) (ug/m3) 1,1, 1-Trichloroethane Acetone Benzene Carbon Tetrachloride Chloroform Dichlorodifluoromethane Ethylbenzene 0.58 3.2 4.5 J 11 J 0.15 L 0.47 L 0.09 L 0.42 L 0.10 L 0.50 L 0.66 3.3 0.20 L 0.87 L ND(0.21) ND(1.2) 3.1 J 7.3 J 0.15 L 0.47 L 0.09 L 0.44 L ND(0.20) ND(0.98) 0.59 2.9 ND(0.21) ND(0.91) Hexane 1.0 3.7 0.18 L 0.64 L Methyl-t-Butyl Ketone 0.23 0.81 0.47 1.7 Methylene Chloride 0.44 1.5 0.12 L 0.43 L Toluene 0.85 3.2 0.42 1.6 Trichlorofluoromethane 0.27 1.5 0.27 1.5 Trichlorotrifluoroethane 0.10 L 0.78 L 0.10 L 0.78 L m/p-xylenes 0.65 2.8 ND(0.41) ND(1.8) o-xylene 0.25 1.1 0.08 L 0.34 L NOTES: ND = Not detected above reporting limits L = estimated value, below the calibration range J = Estimated value Compounds in bold are project target analytes

Probe Design Now Used at Other Sites)

Sources and Significance of Systematic Error: Insufficient or Excessive Purging: Mass Balance dc = Q C C in dt V ( ) C(0) = C 0 purgevolume tq Cin C = = ln V C C in 0 out Purge Volumes 5 4 3 2 0.99 0.95 0.9 0.85 0.8 1 0 0 0.2 0.4 0.6 0.8 1 C o /C in

Sources and Significance of Systematic Error: Insufficient or Excessive Purging: Particle Tracking Tedlar bag sample 0-10 6-L Summa Canister Sample Simulated pressure differential (Pa), streamlines, and travel time (min) Below a slab during air sampling at 1 LPM -20-30 -40-50 L slab = 13 cm L water-table = 1000 cm K slab = 1.0 x 10-10 cm 2 K sub-slab = 5.0 x 10-08 cm 2 K soil = 5.0 x 10-08 cm 2 R w = 0.7 cm 2 g = 0.2-60 -70-80 -90-100 10 20 30 40 50 60 70 80 90 100

Sources and Significance of Systematic Error: Insufficient or Excessive Purging: Void Under Slab V (L) D (ft) 1 1.5 2 2.1 3 2.5 4 2.9 5 3.3 6 3.6 7 3.9 8 4.2 9 4.4 10 4.6 11 4.9 12 5.1 13 5.3 14 5.5 15 5.7 Internal volume of sub-slab probe is insignificant (< 5 cm 3 ) Assume thickness of air space underneath slab is ¼

Sources and Significance of Systematic Error: Insufficient or Excessive Purging: Direct Sampling

Concentration as a Function of Sample Sequence 600 500 Concentration (ppbv) 400 300 200 100 1,1,1-TCA TCE 1,1-DCE c-1,2-dce 0 0 1 2 3 4 5 6 Sampled Volume (L)

Sources and Significance of Systematic Error: VOC loss through tedlar bags Tedlar bag study at GWERD

On-Site GC Analysis of VOCs Using Tedlar Bags

Sampling Sub-Slab Gas with a 6-L Summa Canister

Sub-Slab Concentration (ppbv) 180 160 140 120 100 80 60 40 20 0 Sources and Significance of Systematic Error: VOC loss through tedlar bags Comparison with TO-15 Analysis A B C A B C A B House A TO-15 (7/02) Tedlar Bag (7/02) Tedlar Bag (10/02) 1,1,1-TCA 1,1-DCE TCE c-1,2-dce 1,1-DCA C A B C A B C

Sampling Sub-Slab Gas with a 1-L Summa Canister

Sampling for O 2, CO 2 and CH 4 during Purging

Sources and Significance of Systematic Error: Selection of Sampling Locations

Sources and Significance of Systematic Error: Selection of Sampling Locations 180 House A Sub-Slab Concentration (ppbv) 160 140 120 100 80 60 40 20 A B C A B C A B C A B C TO-15 (7/02) Tedlar Bag (7/02) Tedlar Bag (10/02) A B C 0 1,1,1-TCA 1,1-DCE TCE c-1,2-dce 1,1-DCA

Outdoor/Indoor 1.0? Outdoor Algorithm to Identify sources of VOC in Indoor Air IND NO Indoor/Sub-Slab 1.0? Is VOC in GW or SG in vicinity of bldg? or IND Are Indoor/Sub-Slab ratios available for tracer compounds or radon? NO Outdoor/Indoor 0.33? Outdoor/Indoor 0.67? 0.33 < Outdoor/Indoor < 0.67? Indoor Outdoor Indoor- Outdoor Sub-Surface Is Indoor/Sub-Slab ratio range for tracer or radon? IND Not Subsurface IND NO Outdoor/Indoor 0.33? Outdoor/Indoor 0.67? 0.33 < Outdoor/Indoor < 0.67? Indoor or Indoor Subsurface Outdoor or Outdoor Subsurface Indoor-Outdoor or Indoor-Outdoor Subsurface

Subsurface as a Source of VOCs in Indoor Air (364 Housatonic) VOC Outdoor bsm t ratio m ean ratio m ean ratio GW likely TO-15 TO-15 outdoor/ sub-slab bsmt/ tedlar bsmt/ MW-525 primary 07/16/02 07/16/02 bsm t TO-15 sub-slab (ppbv) sub-slab 01/08/03 source (ppbv) (ppbv) (ppbv) TO-15 tedlar (ug/l) of VOC 1,1,1-TCA 0.58 3.80 1.5E-01 495 7.7E-03 741 5.1E-03 190 sub-surface 1,1-DCE ND(0.25) 2.30 < 1.1E-01 323 7.1E-03 425 5.4E-03 130 sub-surface TCE ND(0.25) 1.50 < 1.7E-01 215 7.0E-03 226 6.6E-03 130 sub-surface c-1,2-dce ND(0.25) 0.57 < 4.4E-01 81 7.1E-03 88 6.5E-03 60 sub-surface 1,1-DCA ND(0.25) 0.52 < 4.8E-01 70 7.5E-03 NA NA 61 sub-surface

Outdoor/Indoor 1.0? Outdoor Indoor/Sub-Slab 1.0? Outdoor/Indoor 0.33? Indoor Is VOC in GW or SG in vicinity of bldg? NO Outdoor/Indoor 0.67? Outdoor IND NO or IND Are Indoor/Sub-Slab ratios available for tracer compounds or radon? 0.33 < Outdoor/Indoor < 0.67? Indoor- Outdoor Sub-Surface Is Indoor/Sub-Slab ratio range for tracer or radon? IND Not Subsurface IND NO Outdoor/Indoor 0.33? Outdoor/Indoor 0.67? 0.33 < Outdoor/Indoor < 0.67? Indoor or Indoor Subsurface Outdoor or Outdoor Subsurface Indoor-Outdoor or Indoor-Outdoor Subsurface

Indoor Source of VOCs, Outdoor/indoor < 1 or indeterminate and indoor/sub-slab < 1 or indeterminate (364 Housatonic) VOC Outdoor bsmt ratio mean ratio mean ratio GW likely TO-15 TO-15 outdoor/ sub-slab bsmt/ tedlar bsmt/ MW-525 primary 07/16/02 07/16/02 bsmt TO-15 sub-slab (ppbv) sub-slab 01/08/03 source (ppbv) (ppbv) (ppbv) TO-15 tedlar (ug/l) of VOC CH2Cl2 0.44 3.90 1.1E-01 ND(21) > 1.9E-01 NA NA ND(10) indoor CHCl3 0.10 L 0.34 2.9E-01 ND(21) > 1.6E-02 NA NA ND(10) indoor MEK ND(0.26) 1.00 < 2.6E-01 ND(39) > 2.6E-02 NA NA ND(10) indoor MTBE 0.23 8.50 2.7E-02 ND(20) > 4.3E-01 NA NA 2.0 indoor heptane ND(0.24) 0.97 < 2.5E-01 ND(21) > 4.6E-02 NA NA ND(10) indoor benzene 0.15 L 0.80 1.9E-01 ND(21) > 3.8E-02 ND(8) IND ND(10) indoor toluene 0.85 5.30 1.6E-01 < 20 > 2.7E-01 ND(30) IND ND(10) indoor ethylbenzene 0.20 L 1.00 2.0E-01 ND(21) > 4.8E-02 NA NA ND(10) indoor m/p-xylene 0.65 3.70 1.8E-01 < 42 > 8.8E-02 NA NA ND(10) indoor o-xylene 0.25 1.50 1.7E-01 ND(21) > 7.1E-02 NA NA ND(10) indoor 1,2,4-TMB ND(0.24) 2.40 < 1.0E-01 ND(21) > 1.1E-01 NA NA ND(10) indoor 1,3,5-TMB ND(0.25) 0.77 < 3.2E-01 ND(21) > 3.7E-02 NA NA ND(10) indoor 4-Ethyltoluene ND(0.25) 1.70 < 1.5E-01 ND(22) > 7.7E-02 NA NA ND(10) indoor ethyl/vinyl acetate ND(0.48) 1.50 < 3.2E-01 ND(42) > 3.6E-02 NA NA ND(10) indoor

Indoor and Outdoor Sources of VOCs, Outdoor/indoor < 1 or indeterminate and indoor/sub-slab < 1 or indeterminate (364 Housatonic) VOC Outdoor bsmt ratio mean ratio mean ratio GW likely TO-15 TO-15 outdoor/ sub-slab bsmt/ tedlar bsmt/ MW-525 primary 07/16/02 07/16/02 bsmt TO-15 sub-slab (ppbv) sub-slab 01/08/03 source (ppbv) (ppbv) (ppbv) TO-15 tedlar (ug/l) of VOC CCl4 0.09 L 0.23 L 3.9E-01 ND(21) > 1.1E-02 NA NA ND(10) indoor-outdoor CCl3F(freon11) 0.27 0.82 3.3E-01 ND(21) > 3.9E-02 NA NA ND(10) indoor-outdoor CCl2F2(freon12) 0.66 1.10 6.0E-01 ND(21) > 5.2E-02 NA NA ND(10) indoor-outdoor CCl3CF3(freon113) 0.10 L 0.22 L 4.5E-01 ND(21) > 1.0E-02 NA NA ND(10) indoor-outdoor hexane 1.00 2.40 4.2E-01 ND(22) > 1.1E-01 NA NA ND(10) indoor-outdoor

Indeterminate but not Subsurface Sources of VOCs, Outdoor/indoor < 1 or indeterminate and indoor/sub-slab < 1 or indeterminate (364 Housatonic) VOC Outdoor bsmt ratio mean ratio mean ratio GW likely TO-15 TO-15 outdoor/ sub-slab bsmt/ tedlar bsmt/ MW-525 primary 07/16/02 07/16/02 bsm t TO-15 sub-slab (ppbv) sub-slab 01/08/03 source (ppbv) (ppbv) (ppbv) TO-15 tedlar (ug/l) of VOC PCE ND(0.25) 0.17 L < 1.5E+00 ND(21) > 8.1E-03 NA NA ND(10) IND-not sub-surf ace CHBrCl2 ND(2.2) 0.14 J,L < 1.6E+00 ND(190) > 7.4E-04 NA NA ND(10) IND-not sub-surf ace cyclohexane ND(0.50) 0.57 < 8.8E-01 ND(43) > 1.3E-02 NA NA ND(10) IND-not sub-surface styrene ND(0.23) 0.29 < 7.9E-01 ND(20) > 1.5E-02 NA NA ND(10) IND-not sub-surface 1,3-butadiene ND(0.50) 0.35 L < 1.4E+00 ND(43) > 8.1E-03 NA NA ND(10) IND-not sub-surf ace 1,3-DCB ND(0.24) 0.10 L < 2.4E+00 ND(21) > 4.8E-03 NA NA ND(10) IND-not sub-surf ace 1,4-DCB ND(0.24) 0.15 L < 1.6E+00 ND(20) > 7.5E-03 NA NA ND(10) IND-not sub-surf ace CS2 ND(0.23) 0.18 L < 1.3E+00 ND(20) > 9.3E-03 NA NA ND(10) IND-not sub-surf ace

Preliminary Results and Findings A protocol has been developed which allows rapid and inexpensive installation of sub-slab vapor probes with minimal disturbance to occupants. At least 3 sub-slab vapor probes samples should be installed in a typical home to calculate indoor air/subslab concentration ratios and assess associated spatial variability. Commercial buildings with larger area slabs will require more probes. Placement of sub-slab probes in the center of a slab does not consistently result in detection of higher vapor concentrations. The sub-slab sampling protocol appears to be free of systematic error

Preliminary Results and Findings An algorithm or flowchart has been developed to discern the source(s) of VOCs in indoor. The following data (and associated data is necessary) - indoor air samples (TO-15 or equivalent) - Outdoor air samples (TO-15 or equivalent) in the vicinity of indoor air sampling locations - Sub-slab air samples (on-site GC analysis, TO-15 or equivalent) - A conservative VOC compound in sub-slab air (e.g., 1,1-DCE) or use of radon to calculate indoor-air/sub-slab concentration ratios. - VOC analysis in ground-water and/or soil-gas (TO-15 preferred) in the vicinity indoor sampling locations may be necessary at some locations)

Questions?