Southern Cleaners & Laundry Jacksonville, North Carolina CASE STUDY Vapor Intrusion Pathway: Evaluation and Risk Assessment October 2006 Presented By: Delonda Alexander North Carolina Dry-Cleaning Solvent Act (DSCA) Program North Carolina Department of Environment and Natural Resources Division of Waste Management 401 Oberlin Road Raleigh, North Carolina Tel: (919) 508-8444 Fax: (919) 733-4811 1
Site Location 2
SITE LOCATION New River 3
Site History Dry cleaning operations conducted from 1940 s to 1990 s Site currently used as a commercial laundry facility for uniforms and linens Impacts initially discovered in 1994 during UST removal Varsol, gasoline and fuel oil 4
Aerial View 5
Southern Cleaners 6
Southern Cleaners 7
Southern Cleaners 8
Southern Cleaners 9
Southern Cleaners Storm Drain 10
Storm Drain 11
New River 12
Wantland Spring and New River 13
Wantland Spring Historic Site 14
Wantland Spring 15
Spring Fed? 16
Just Weird Happy Halloween! 17
Investigations, More Investigations. Assessment activities began in April 1994 To date: 32 monitoring wells installed 30 additional soil borings advanced 72 direct push groundwater samples collected 6 borings advanced for membrane interface probe (MIP) logging All properties within 0.5 mile serviced by municipal water and sewer no private wells located 18
Investigations, More Investigations. Air sparging and soil venting system operated at site 1997 to 1999 and 2001 to 2002 Enhanced bioremediation attempted with biweekly sugar solution injections in 1998 Impacts confirmed to: On-site soil On-site and off-site groundwater Wantland Spring To date, more than $500,000 spent on investigation 19
Site Geology Shallow 0-8 Intermediate 8-23 Deep 23 50 20
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The Chain of Events The DSCA Program project manager gave a presentation to the County commissioners regarding ongoing assessment activities to keep them informed After the commissioners saw the plume maps started asking questions about potential vapor intrusion issues The wife of one of the commissioners works in the tax office over the plume How will this affect building the new jail? 24
The Chain of Events cont d The County calls an impromptu press conference The DSCA project manager has to answer media questions about the threat of vapor intrusion The DSCA project manager agrees to conduct indoor air sampling as soon as possible 25
Back at the Office.. Staff is scrambling to get background information and to educate public relations personnel County officials demand a hotline number for people to call if they have concerns do we want to do that? Organizing meeting with our state contractor to conduct indoor air testing as soon as possible 26
A Little Back History Community already sensitive to PCE and TCE contamination in early 1980 s it was revealed that a water supply serving families on Camp Lejeune was contaminated with PCE and TCE County trying to expand jail located in contaminated area downtown dispute with city officials Owner of contaminated site was a former city councilman 27
So..Indoor Air Sampling On February 23, 2006, indoor air sampling was conducted in three commercial buildings (Tax Office, USO Building, Probation Office) and one residence (12 Tallman) Samples collected in SIM certified SUMMA canisters 8 hour sampling period Samples analyzed using EPA Method TO-15 (SIM) 28
Indoor Air Sampling Locations Indoor Air and Soil Vapor Sampling Locations Former Southern Cleaners, Jacksonville, North Carolina Indoor Air Sampling Location Soil Vapor Sample Probe USO (9 Tallman Street) SITE USO-2-basement USO-3-crawspace Tax Office (39 Tallman Street) USO-1 12 Tallman Street (Res) #3 #2 #2 #1 #1 #4-upstairs #1 #3- crawlspace #4 SV-2 #2 #1 SV-1 #3- crawlspace Probation Office 14 Tallman Street (Res) 29
USO Building 30
USO Building Sampling 31
12 Tallman Residence 32
12 Tallman Residence Sampling 33
12 Tallman Residence - Crawl Space Sampling 34
Tax Office Sampling 35
Not OK II Sample 36
Sample Results (2/23/06) Location Detected COC 2/23/06 Results Max. (ug/m 3 ) 12 Tallman Residence PCE 4.6 (crawl space) TCE 0.11 USO Building PCE 0.8 TCE 0.12 Cis 1,2-DCE 0.055 Trans 1,2-DCE 0.067 Vinyl chloride 0.068 Tax Office PCE 11.0 TCE 0.63 Cis 1,2-DCE 0.26 Trans 1,2-DCE 0.7 Vinyl chloride 0.082 37
The Toxicologist. Policy decision if measured indoor air concentrations exceed acceptable risk of 1 x 10E-04, occupants will be evacuated or immediate abatement actions will be taken So, the calculations were performed using the Draft EPA OSWER Vapor Intrusion guidance using an acceptable target risk of 1 x 10E-04 and HQ = 1.0 Carcinogenic and non-carcinogenic target indoor air concentrations were calculated for each contaminant the more stringent concentration was chosen as the target indoor air concentration 38
Carcinogens C cancer (ug/m 3 ) = [(TCR*AT c )/(EF*ED*URF) C cancer = target indoor air concentration (ug/m 3 ) TCR = target cancer risk (1 x 10-4 ) AT c = averaging time (25,550 days) EF = exposure frequency (250 days/yr) ED = exposure duration (25 years) URF = unit risk factor (ug/m 3 ) -1 Exposure frequency and exposure duration altered for commercial setting instead of EPA s residential setting - exposure frequency: 250 days/yr (not 350 days/yr) - exposure duration: 25 yrs (not 30 yrs) 39
Non-Carcinogens C non-cancer (ug/m 3 ) = (THQ*RfC*1000ug/mg) C non-cancer = target indoor air concentration (ug/m 3 ) TCR = target hazard quotient (1.0) RfC = reference concentration (mg/m 3 ) RfC for PCE derived using EPA Region 9 Preliminary Remediation Goals reference dose for inhalation (RfDi) converted to RfC using: RfC (mg/m 3 ) = RfD (mg/kg/d)*(1/ir)(m 3 /d) -1 *BW (kg) IR = inhalation rate (20 m 3 /d) BW = body weight (70 kg) 40
Non-Carcinogens Since the constituents detected affect the same target organ, the target indoor air concentration for non-carcinogens was divided by the number of constituents detected to apportion the HQ equally Example: For PCE C non-cancer = 105 ug/m 3 If four constituents detected 105 ug/m 3 / 4 = 26.25 ug/m 3 If three constituents detected 105 ug/m3 / 3 = 35 ug/m3 41
Sample Results and Targets (2/23/06) Location Detected COC 2/23/06 Results Max. (ug/m 3 ) Acceptable Level (ug/m 3 ) 12 Tallman Residence PCE 4.6 35 (crawl space) TCE 0.11 2.2 USO Building PCE 0.8 26.25 TCE 0.12 11.1 Cis 1,2-DCE 0.055 26.25 Trans 1,2-DCE 0.067 52.5 Vinyl chloride 0.068 76 Tax Office PCE 11.0 35 TCE 0.63 11.1 Cis 1,2-DCE 0.26 35 Trans 1,2-DCE 0.7 42 Vinyl chloride 0.082 60.9 42
Couldn t Just Stop There Discussion with the state-lead contractor didn t use all the Summa canisters during the initial sampling event could sample additional residence On March 6, 2006, three indoor air samples collected at 14 Tallman residence 43
14 Tallman Residence 44
14 Tallman Residence Sampling 45
Sampling Results (3/6/06) Compound vinyl chloride 1,1-dichloroethene trans-1,2-dichloroethene cis-1,2-dichloroethene trichloroethene tetrachloroethene Compound vinyl chloride 1,1-dichloroethene trans-1,2-dichloroethene cis-1,2-dichloroethene trichloroethene tetrachloroethene Compound vinyl chloride 1,1-dichloroethene trans-1,2-dichloroethene cis-1,2-dichloroethene trichloroethene tetrachloroethene Sample ID / Sample Date / Concentration March 6, 2006 INDOOR AIR 14 Tallman (Res)-1 ug/m 3 0.16 0.30 0.28 0.13 0.49 0.17 14 Tallman (Res)-2 ug/m 3 <0.026 0.29 0.18 0.41 64 0.74 14 Tallman (Res)-3 ug/m 3 <0.030 <0.040 <0.040 <0.040 2.8 0.75 46 Sample Location / Description First Floor 14 Tallman St. In dining room. Sample Location / Description First Floor 14 Tallman St. At intersection of master bedroom, main bathroom and kitchen. Sample Location / Description Crawlspace of 14 Tallman St.
Don t need to say more.. 47
14 Tallman Air Duct 48
14 Tallman Residence Florida Heat Pump 49
Geothermal Heat Pump Well 50
14 Tallman Air Ducts 51
Additional Sampling On March 29, 2006, two soil gas vapor samples and six additional indoor air samples collected at 14 Tallman residence Piping from heat pump was was found to lead to outside of air intake unit piping was capped prior to this round of sampling 52
Indoor Air and Soil Vapor Sampling Locations Indoor Air and Soil Vapor Sampling Locations Former Southern Cleaners, Jacksonville, North Carolina Indoor Air Sampling Location Soil Vapor Sample Probe USO (9 Tallman Street) SITE USO-2-basement USO-3-crawspace Tax Office (39 Tallman Street) USO-1 12 Tallman Street (Res) #3 #2 #2 #1 #1 #4-upstairs #1 #3- crawlspace #4 SV-2 #2 #1 SV-1 #3- crawlspace Probation Office 14 Tallman Street (Res) 53
14 Tallman Indoor Air Sampling (3/30/06) 54
14 Tallman Residence Crawl Space 55
Soil Vapor Sampling Point 56
Sampling Results (3/6/06 & 3/29/06) Compound vinyl chloride 1,1-dichloroethene trans-1,2-dichloroethene cis-1,2-dichloroethene trichloroethene tetrachloroethene Compound vinyl chloride 1,1-dichloroethene trans-1,2-dichloroethene cis-1,2-dichloroethene trichloroethene tetrachloroethene Sample ID / Sample Date / Concentration March 6, 2006 March 29, 2006 INDOOR AIR 14 Tallman (Res)-2 14 Tallman (Res)-2 ug/m 3 ug/m 3 <0.026 <0.037 0.29 <0.058 0.18 <0.58 0.41 <0.12 64 <0.16 0.74 2.5 14 Tallman (Res)-3 14 Tallman (Res)-3 ug/m 3 <0.030 <0.040 <0.040 <0.040 2.8 0.75 ug/m 3 <0.037 <0.058 <0.58 <0.12 <0.16 1.4 Sample Location / Description First Floor 14 Tallman St. At intersection of master bedroom, main bathroom and kitchen. Sample Location / Description Crawlspace of 14 Tallman St. 57
Sampling Results (3/29/06) Compound vinyl chloride 1,1-dichloroethene trans-1,2-dichloroethene cis-1,2-dichloroethene trichloroethene tetrachloroethene Compound vinyl chloride 1,1-dichloroethene trans-1,2-dichloroethene cis-1,2-dichloroethene trichloroethene tetrachloroethene 14 Tallman (Res)-4 March 29, 2006 ug/m 3 <0.039 <0.060 <0.60 <0.12 <0.16 3.4 14 Tallman (Res)-5 ug/m 3 0.041 <0.055 <0.55 <0.11 <0.15 2.6 14a Tallman (Res)-1 Compound ug/m 3 vinyl chloride <0.037 1,1-dichloroethene <0.058 trans-1,2-dichloroethene <0.58 cis-1,2-dichloroethene <0.12 trichloroethene <0.16 tetrachloroethene 1.9 Sample Location / Description First Floor 14 Tallman St. In utility room. Utility room door kept closed during sampling period. Sample Location / Description First Floor 14 Tallman St. In hall near Southwest side of house. Sample Location / Description Second Floor 14 Tallman St. In hall outside bedrooms. 58
Soil Gas Results (3/29/06) Compound vinyl chloride 1,1-dichloroethene trans-1,2-dichloroethene cis-1,2-dichloroethene trichloroethene tetrachloroethene Compound vinyl chloride 1,1-dichloroethene trans-1,2-dichloroethene cis-1,2-dichloroethene trichloroethene tetrachloroethene March 29, 2006 SV-1 ug/m 3 <11 <17 <17 <17 <23 1000 SV-2 2 ug/m 3 <10 <16 <16 <16 <22 4200 Sample Location / Description Soil gas sample. East side of 14 Tallman St residence; 5 ft deep Sample Location / Description Soil gas sample. West side of 14 Tallman St residence; 5 ft deep 59
What Does It All Mean? None of the indoor air sampling results exceed the calculated acceptable risk level based on a risk of 1 x 10E-04 except one result for TCE Indoor air concentrations at 14 Tallman residence will exceed individual excess lifetime cancer risk of 1 x 10E-06 The soil gas results exceed EPA s OSWER guidance Our policy if it exceeds risk of: 1 x 10E-04 evacuate, take immediate action 1 x 10E-05 monitor or take additional actions 1 x 10E-06 confirm results, take remedial actions 60
Now What? More soil vapor sampling is scheduled with the state-lead contractor Performance of a risk assessment authorized using draft North Carolina risk-based guidance procedures 61
Risk Assessment Process Divided the area of impact into 2 exposure units (EUs) Developed an Exposure Model (EM) for each EU Calculated media-specific representative concentrations for each complete receptor-exposure pathway in each EU Performed a Tier 1 risk assessment Evaluated impacts to New River and vapor intrusion 62
Exposure Units EU Description Area (acres) 1 On-site Area (Southern Cleaners & Laundry) 1.3 2 Off-site Areas (between site and New River) 40 N/A Surface Water Feature (New River) N/A 63
Recent Available Data EU Monitoring Wells Direct Push Borings Soil Borings Soil Vapor Samples Indoor Air Samples 1 9 13 19 N/A N/A 2 18 25 2 3 21 N/A Not available Additionally, two surface water samples have been collected from New River, and two surface water samples have been collected at Wantland Spring. 64
Exposure Model for EU 2 Land Use: Residential (current and future) Media of Concern: Soil vapor Indoor air Groundwater Surface water (New River) Receptors: Current resident (child, adult, age-adjusted), Future construction worker 65
Complete Routes of Exposure (EU 2) Current/Future Resident Outdoor & indoor inhalation of vapor emissions from groundwater. Future Construction Worker Outdoor inhalation of vapors from groundwater, and Dermal contact with groundwater. 66
Representative Concentrations Calculated for each media of concern for each receptorexposure pathway combination Concentrations calculated included (i) maximum detected concentration and (ii) average concentration For soil, data from the most recent (2005) sampling was considered For groundwater, data collected since 2001 was considered For soil vapor, each sample was assessed separately For indoor air, data from each structure was averaged 67
Models and Equations Models required for indirect exposure pathways: Johnson & Ettinger - soil and groundwater to indoor air Jury, Cowherd, Gaussian Dispersion - soil to outdoor air Farmers and Box Model - groundwater to outdoor air 68
Tier 1 Soil Vapor Results Location Sample ID Sampling Date PCE (ug/m 3 ) 14 Tallman SV-1 3/29/06 1000 14 Tallman SV-2 3/29/06 4200 For PCE: Tier 1 Screening Level Indoor Inhalation of Vapors = 31,700 ug/m 3 Tier 1 Screening Level Outdoor Inhalation of Vapors = 1,680,000 ug/m3 69
Example Tier 1 Screening Levels (Resident)* Chemical of Concern Subsurface Soil (mg/kg) Indoor Inhalation of Vapors 70 Outdoor Inhalation of Vapors Groundwater (mg/l) Indoor Inhalation of Vapors Outdoor Inhalation of Vapors Tetrachloroethylene 4.92E-02 2.61E+00 4.44E-02 5.88E+01 Trichloroethylene 4.22E-03 2.24E-01 3.77E-03 4.46E+00 cis-1,2-dichloroethylene 1.16E+01 5.78E+02 3.47E+01 2.55E+04 trans-1,2-dichloroethylene 7.41E+00 3.71E+02 1.59E+01 1.55E+04 1,1-Dichloroethylene 7.12E-01 3.56E+01 1.15E+00 1.51E+03 Vinyl chloride 5.58E-03 2.96E-01 1.42E-02 2.20E+01 For Groundwater: Average PCE concentration at site = 1.2 mg/l Maximum PCE concentration at the site = 15.0 mg/l * Developed based on default inputs
Conclusions of the Tier 1 Risk Assessment All soil vapor concentrations were below the Tier 1 screening level protective of a resident Indoor air concentrations for PCE and TCE exceeded Tier 1 screening levels protective of a resident in all five of the structures that were sampled Concentrations in groundwater discharging into New River are below applicable surface water quality standards. 71
Now What? Planned additional soil vapor sampling put on hold Identify data gaps for Tier 2 site-specific risk assessment Collect data and conduct Tier 2 risk assessment 72
Lessons Learned Always expect the media when dealing with government officials don t get ambushed Don t let the pressure of the moment back you into a corner or cause knee-jerk reactions Just because you have equipment left over don t feel like you have to use it Collect soil geotechnical parameters and any site-specific data you may need for a site-specific risk assessment early on 73
Lessons Learned Would have done more soil gas sampling first before going inside buildings Gather more background data on buildings before sampling Know your acceptable target concentrations before sampling Develop guidance on handling vapor intrusion 74
Questions? 75