www.agisurveys.net Slide 1 Passive Gas Environmental Site Assessment and Monitoring Mark A. Arnold, CPG, RG Prepared for:
Outline of Presentation www.agisurveys.net Slide 2 Why Passive Gas Sampling? AGI Universal Sampler Sampling and Analysis Applications of Passive Gas Surveys Optimizing Monitoring Well Placement Site Characterization Long Term Monitoring Indoor Air Vapor intrusion Groundwater Summary
Why Passive Gas Sampling? www.agisurveys.net Slide 3 Geological Universe Active Passive Volatile Semivolatile Shorter Sampling Longer Sampling Organic Compound Universe
AGI Universal Sampler Formerly known as the GoreSorber Module Effective in air, soil-gas and water Collects VOCs/SVOCs Lower total sampling costs No refrigeration for shipping Time integrated sampling gives ppt sensitivity US EPA Verification of the method for soil gas and groundwater 1) GORE Membrane (eptfe) Designed for diffusion Waterproof, gas permeable Inert, no off-gassing, no adsorption Protects sample integrity 2) Hydrophobic sorbents for detection of VOCs, SVOCs GORE-TEX Membrane Water & soil particles remain outside Adsorbents Vapors pass through www.agisurveys.net Slide 4
www.agisurveys.net Slide 5 Module Installation Ground Installation Air Installation Typically 0.5-1m depth Indoor Surface sealed with impermeable cork Outdoor Permanent sample port Dry Cleaner - Courtesy Kansas Department of Health & Environment
Module Installation www.agisurveys.net Slide 6 Sub-aqueous sediment Groundwater No-purge passive sampling River Sediment Vertical Profiling in Wells
Commonly Detected Compounds www.agisurveys.net Slide 7 Volatiles Vinyl Chloride 1,1-Dichloroethene Methyl t-butyl ether Benzene Toluene Ethylbenzene o-xylene m,p-xylene Octane 1,1-Dichloroethane 1,2-Dichloroethane 1,1,1-Trichloroethane 1,1,2-Trichloroethane 1,1,1,2-Tetrachloroethane 1,1,2,2-Tetrachloroethane trans-1,2-dichloroethene cis-1,2-dichloroethene Trichloroethene Tetrachloroethene Chloroform Carbon Tetrachloride Chlorobenzene 1,4-Dioxane Freons Fuel Oxygenates Semi-volatiles 1,3,5-Trimethylbenzene 1,2,4-Trimethylbenzene 1,2-Dichlorobenzene 1,3-Dichlorobenzene 1,4-Dichlorobenzene Undecane Tridecane Naphthalene 2-Methylnaphthalene Pentadecane Acenaphthene Acenaphthylene Fluorene Phenanthrene Anthracene Fluoranthene Pyrene Other Compounds Pesticides/Herbicides PCB Cogeners Explosives Chemical Warfare Agents NOTE: This is not a comprehensive list of compound detection or analytical capabilities.
Partial List of Detectable Mixtures & Fluids www.agisurveys.net Slide 8 Dry Cleaning Fluids Gasolines Diesel Fuels Heating Oils Fuel Additives Jet Fuels Solvents Pesticides Refrigerants (Freons) PCB s Polycyclic aromatic hydrocarbons (PAHs) Chemical Warfare agents Explosives Mineral Spirits Herbicides
www.agisurveys.net Slide 9 Accreditations and Affiliations Dedicated Fixed Laboratory (Newark, DE) Modified EPA method 8260/8270 (TD\GC\MS) Mass and concentration data for air, soil-gas and water ISO 17025, DoD ELAP accreditation by A2LA
Common Applications of Passive Gas Surveys Site Assessment (air, soil-gas and water) Property transfers Long-term Monitoring Pipeline Integrity www.agisurveys.net Slide 10
Typical Sites for Passive Gas Surveys Industrial & manufacturing complexes Petroleum refining complexes Bulk fuel storage facilities Retail gas stations Dry cleaners Chemical plants Military bases Brownfields Pipelines Landfills Manufactured gas plants www.agisurveys.net Slide 11
Case Studies www.agisurveys.net Slide 12 Optimizing Monitoring Well Installation Site Characterization Remediation and Property Transfer Monitoring Indoor Air Vapor Intrusion Groundwater
Optimizing Monitoring Well Placement www.agisurveys.net Slide 13 Active fuel storage terminal (NE USA) 1 to 7 m to groundwater 33 acres/13 hectares, 100 samplers at 30m spacing Required monitoring wells reduced from 33 to 15 by regulatory agency Savings of $100,000 on well construction ($25K quarterly) Middle Distillates, C 7 -C 10 200 feet
Tooele Army Depot, Utah Vehicle maintenance, ammunition destruction CVOC impact to groundwater Main GW Plume Secondary GW Plume Depth to groundwater is 30 to 125 m Poorly sorted sand and gravel P&T operating cost is $2 million/year 30 years expected to site closure No remedial progress in 7 years Suspected unknown sources Chose to perform AGI Survey Source Areas Soil Gas Survey www.agisurveys.net Slide 14
Tooele Army Depot www.agisurveys.net Slide 15 Unlined Wastewater Ditches Groundwater Flow 800 acres/320 hectares 950 samplers (yellow dots) 5 separate deployments Spaced 15 to 100m 1 meter installation depth 14 day exposure 0 1,000 ft Warehouse Area
Tooele Army Depot www.agisurveys.net Slide 16 AGI Survey - TCE SVE Pilot Study Oil/Water Separator TCE 6,000 lbs 1000 feet 0 1,000 ft Storm sewer directed TCE
Tooele Army Depot www.agisurveys.net Slide 17 AGI Survey - PCE 1000 feet 0 1,000 ft No record of PCE use Clerical error (recorded as TCE)
Tooele Army Depot www.agisurveys.net Slide 18 Unidentified source found containing ~6,000 lbs TCE Entire plume reach MCL s in 2 years & remediation system shut down 20 years ahead of schedule Total expenditures ~$400,000 for AGI surveys Savings of ~$40,000,000 in remediation costs
Dry Cleaner Site - Arizona Dry Cleaner PCE Shallow soils and fractured granite Groundwater at 90 feet Former residential site converted to commercial TCE AGI Sampler Location Dry Cleaner PCE detected in nearby water wells 55 modules (25-foot intervals) installed at 3 feet beneath asphalt, building slab and in sewer trenches for 10 days Abandoned Septic System AGI Sampler Location www.agisurveys.net Slide 19
Dry Cleaner Site - Arizona www.agisurveys.net Slide 20 Conclusions Dry cleaner source area confirmed (PCE) Previously unidentified TCE source area found (residents used TCE to flush septic system) Remediation plan refined to include TCE source area
Chemical Distribution Facility Eastern USA Background Active chemical storage and distribution facility, Eastern US Very fine sand over alluvial sand, silt and clay Groundwater at 15 to 24 foot depth Data from installed wells indicated that contamination was migrating off-site and the extent was unknown AGI Survey 51 AGI passive samplers over 10 acres Regular grid, 50 foot spacing, 3 foot depth 14-day exposure Modified EPA method 8260/8270 TD/GC/MS analysis www.agisurveys.net Slide 21
Chemical Distribution Facility Eastern USA 1,1 DCA (ug) 200 feet www.agisurveys.net Slide 22
Chemical Distribution Facility Eastern USA 1,1,1 TCA (ug) 200 feet www.agisurveys.net Slide 23
Chemical Distribution Facility Eastern USA Conclusions After the AGI Survey the site owner was able to install one additional nested well set, instead of several. Significant savings compared to alternative site assessment approaches. www.agisurveys.net Slide 24
Petroleum Facility - Post-remediation Monitoring Background Petroleum refining and storage facility Site characterization and remediation monitoring Significant decrease in BTEX plume extent after 2 years of extraction remediation (over 30-fold decrease of BTEX in soil gas) www.agisurveys.net Slide 25
Gas Station Property Transfer Monitoring (SE USA) www.agisurveys.net Slide 26 Time zero 6 months 1000 100 10 1,160 m 2 390 m 2 10 meters 10 meters 1 10 months 24 months BTEX (ug) 330 m 2 70 m 2 10 meters 10 meters
Gas Station Property Transfer Monitoring (SE USA) Background Gas station seller seeking method to monitor post-sale fuel release Baseline and follow-up surveys revealed new release New owner held liable for clean-up The AGI Survey saved the seller more than $100,000 in upgrades to the biosparge system www.agisurveys.net Slide 27
Gas Station Property Transfer Monitoring (SE USA) www.agisurveys.net Slide 28 BTEX Time zero 100 m 2 BTEX 12 months 940 m 2 Existing pre-sale contamination under pump island New contamination discovered after third AGI sampling event (12 months after sale)
Residential Indoor Air Sampling Home near Washington, DC Three rooms AGI samplers deployed in three rooms for 1, 3 and 7 days Calibrated batterypowered pumps pulled air through sorbent tubes for ~5 hours (TO-17 method) www.agisurveys.net Slide 29
www.agisurveys.net Slide 30 AGI Passive Sampling (ug/m 3 ) Residential Indoor Air Sampling 120 100 80 60 40 20 0 Comparison of AGI and TO-17 Concentrations Bedroom Dining Room Basement Dining Room y = 0.9575x R 2 = 0.9921 0 20 40 60 80 100 120 Active Sampling (ug/m 3 ) Notes: - Active used same adsorbent mix and analysis method - Compounds plotted include: BTEX, Benzene, Toluene, PCE, 1,4 DCB, ChCl3, CCl4 - Active over 5 hours in morning of initial sampling - Passive sampling over 24 hours of initial sampling - Un-inhabited Dining Room correlation = 0.99 - Inhabited Bedroom and Basement correlation = 0.97 AGI air survey easier to conduct and less expensive then TO-17 (no pumps, calibration, etc)
Vapor Intrusion Survey Post-Explosion www.agisurveys.net Slide 31 Propane explosion in warehouse basement at Manufacturing Facility, Mid-Atlantic US, rural Mercaptan-like odor in indoor and outdoor air Intrusion of propane suspected beneath slab during heavy rain Leak in exterior pipeline located following explosion 46 AGI passive samplers on 1.85 acres in regular grid, 50 foot spacing, 2 foot deep, seven-day exposure Sub-slab modules installed under the building AGI survey delineated extent of propane and organosulfurs (oxidized mercaptans) in the soils three months after explosion Soil turning was recommended to accelerate natural attenuation of residual propane in the soils.
Vapor Intrusion Survey Post-Explosion www.agisurveys.net Slide 32 3 months after explosion Propane(ug)
Vapor Intrusion Survey Post-Explosion www.agisurveys.net Slide 33 3 months after explosion Organosulfur (ug)
Passive vs. Conventional GW Sampling www.agisurveys.net Slide 34 Military base Mid-Atlantic US 30 years of munitions testing Large network of monitoring wells Chlorinated solvents - ~2,000ug/L 30 ft depth to groundwater Unconsolidated alluvial deposits Modules at mid-point of screened intervals Low-flow groundwater sampling followed Two co-sampling events
www.agisurveys.net Slide 35 Military Base - Passive Water Monitoring 1,1,2,2-Tetrachloroethane Phase 2 AGI Sampler Data Phase 2 - Groundwater Data 26 wells sampled Passive maps match low-flow sampling maps Passive has greater sensitivity allowing better plume delineation 70% cost savings
Cost Analysis www.agisurveys.net Slide 36 Traditional Groundwater Sampling Item Units Unit Description Extended Cost Project management 42 Hours $2,145 Field crew 235 Hours $12,993 Equipment pump 1 Lump sum $1,765 Purge water disposal 0 Disposal fee * Laboratory costs 26 Samples $7,452 TOTAL $24,355 AGI Water Quality Monitoring Item Units Unit Description Extended Cost Project management 4 Hours $204 Field crew 31 Hours $1,324 Equipment consumables 1 Lot charge $100 Laboratory costs 26 Samples $5,070 TOTAL $6,698 * Note: No purge water disposal costs included due to on-site treatment. However, purge water handling is typically a large part of a groundwater sampling budget. $6,698 vs. $24,355 = ~70% Cost Savings
Summary www.agisurveys.net Slide 37 The AGI technology is a universal passive gas collector for the detection of trace levels of VOCs and SVOCs in air, soil gas and groundwater. The technology helps to lower costs by minimizing field costs, optimizing monitoring well placement, and remediation designs. The results in air, soil gas and groundwater are comparable and, in some cases, superior to more expensive traditional sampling methods.
Additional Information www.agisurveys.net Slide 38 Thank You For additional information contact: Mark Arnold AGI 303 952 4208 arnold@agisurveys.net