The Role of Vapor Intrusion and the Challenges of Reporting Representative and Relevant Data

Transcription

1 The Role of Vapor Intrusion and the Challenges of Reporting Representative and Relevant Data Chris Anderson Product Manager, Air November 16 th , TestAmerica Analytical Testing Corp. All rights reserved. TestAmerica & Design TM are trademarks of TestAmerica Analytical Testing Corp. What Is Vapor Intrusion? The migration of volatile chemicals from the subsurface into overlying buildings USEPA

2 Vapor Intrusion Pathway Last Exposure Pathway to be Addressed Significant Nationwide Issue Numerous sites contaminated with volatile compounds A significant number may have conditions favorable for Vapor Intrusion Vapor Intrusion maybe the dominant exposure pathway New sites being identified Closed sites being re-opened by NYDEC, NJDEP, EPA, others? VI Exposure Human Health Risk via Inhalation. Typical adult drinks 2 liters of water a day and inhales 20,000 liters per day = a 10x exposure factor On average people spend 90% of their time indoors Some VOCs have low odor thresholds Henry Schuver USEPA 3 Why Worry About VI? It is a regulatory requirement in some states ASTM Standard for property transfers Sites being reopened and reassessed in some states The indoor air pathway can be the dominant exposure risk Modeled risks may over estimate concentrations There has been litigation for not addressing potential VI. ~ Litigation against responsible parties ~ Litigation against environmental professionals 4 2

3 Vapor Intrusion EPA The migration of volatile chemicals from the subsurface into overlying buildings (USEPA 2002) EPA Office Inspector General on the 2002 Vapor Intrusion Guidance Lack of Guidance on Vapor Intrusion Impedes Efforts to Address Indoor Air Risks Recommendations Identify and publicly report what in the OSWER s November 2002 draft vapor Intrusion guidance is valid and what needs to be updated Issue final vapor intrusion guidance that incorporates: Updated toxicity values Use of multiple lines of evidence Superfund 5 year reviews Preemptive mitigation Institutional controls and deed restrictions are appropriate How risks from petroleum hydrocarbon vapors should be addressed 6 Train EPA and State staff and managers and other parties on the newly updated, revised, and finalized guidance document. 3

4 EPA s Review of the Vapor Intrusion Guidance It s a lot more complicated than indicated in the 2002 Guidance Tier 1 Screening Tables Tier 2 ~ Using Groundwater for Screening appears to be valid ~ External soil gas data is problematic ~ Multiple lines of evidence approach appears valid ~ Early Indoor Air testing appears valid Tier 3 More flexibility on duration of indoor air sampling. Final VI Guidance is expected in November of National Variability In the absence of Federal guidance approximately 30 States have written some level of VI guidance and/or rule 12 states certify for typical VI parameters ~ 250 Laboratories are NELAC accredited for air analyses; ~ 10% of all NELAC labs Screening values vary widely by State Compound CA Indoor Screening Level PA Indoor Screening Level Naphthalene ug/m ug/m 3 Background levels can exceed screening levels 8 4

5 Useful VI Documents ITRC is a state-led coalition includes industry, stakeholders to achieve regulatory acceptance of environmental technologies 2005 Vapor intrusion Team formed; 19 States participated with API, ASTM, EPA and industry ITRC VI Team publish two documents in January 2007 Uses the concepts of: Conceptual Site Model, Multiple lines of evidence Weight of evidence Provides a Vapor Intrusion Tool Box Covers in an iterative stepwise (13) process VI evaluations from Investigation through Mitigation. Does not address: Compounds, Screening or Risk levels 9 ASTM Standard E ASTM Standard E June 2010 Standard Guide for Vapor Encroachment Screening on Property Involved in Real Estate Transactions 10 Objectives Objectives guiding the development of this practice are: To synthesize and put into writing good commercial and customary practice for conducting a Vapor Intrusion Assessment on a property involved in a real estate transaction To supplement a Phase I environmental site assessment (ESA) conducted in accordance with Practice E1527, To ensure that the process for assessing vapor intrusion is practical and reasonable To provide an industry standard for a Vapor Encroachment Conditions (VEC) on a property involved in a real estate transaction. Maybe purchased at; 5

6 EPA Brownfield s Brownfields Technology Primer: Vapor Intrusion Considerations for Redevelopment (EPA 542-R ). This primer is designed for land revitalization stakeholders concerned about vapor intrusion, including property owners, municipalities, and real estate developers. It provides an overview of the vapor intrusion issue and how it can affect redevelopment. It also summarizes techniques for quickly and cost effectively assessing the potential for vapor intrusion, as well as techniques for mitigating it. The topics covered will familiarize stakeholders with options for addressing vapor intrusion to help them communicate with their project contractors and consultants (March 2008, 48 pages). View or download at Sub-Slab Probe installation 12 6

7 Soil Gas Sampling Soil Porosity Concentration Gradient CASTC Draft Guidance 2005 Use a flow restrictors/ flow controllers maximum flow rate of 200 mls per minute 13 EPA Studies Identify Techniques for Critical Leak Testing Prior to Soil- Vapor Sampling EPA s National Risk Management Research Laboratory (NRMRL) recommends that leak testing always precede soil-gas sampling, especially in media of lower permeability, until the integrity of a borehole is well established. x

8 Tracer Gas 15 Leak Check with Liquids IPA at 4,000,000 ppbv Isopropyl Alcohol (isopropanol) Sample with high level of IPA from field leak checking All hits diluted out to Non-detects. QC samples diluted LCS sample; mid-range standard The leak is not detected until laboratory analysis! 16 8

9 17 Consumer Activities Household Products Building Materials & Furnishings Ambient (outside) Air Important: Conduct a building survey before sampling Sources of Background Indoor Air Contamination Common Household Sources of Background Indoor Air Contamination Acetone Formaldehyde d Benzene n-heptane Bromomethane n- Hexane 2-Butanone (MEK) Methylene chloride Chlorobenzene Methyl isobutyl ketone Chloroethane Methyl tert butyl ether Source: J. Boyer, NJDEP Chloroform Styrene Cyclohexane 1,1,2,2-Tetrachloroethane 1,4-Dichlorobenzene Tetrachloroethene (PCE) Dichlorodifluoromethane Toluene 1,1-Dichloroethane 1,1,1-Trichloroethane 1,3-Dichloropropene Trichloroethene (TCE) Ethylbenzene Xylenes, total Sampling Considerations Rain guards for ambient sampling Particulate filters for dusty conditions Stainless steel sample Ts for co-located duplicates Swagelok fittings for sample line connection to flow controller Flow controllers set for expected ambient temperature Tubing or hangers for collection of breathing zone samples Flow controller setting; 1, 2, 4, 8, 24 hour or other 9/16 box wrench for Swagelok fitting NIST traceable pressure gauge Community awareness Its not a bomb! In-line filter Source: restek 18 9

10 Sample Tubing Can Impact Data Field Sampling Media Tubing options: Background contribution: Stainless steel < Nylaflow < Teflon-FEP < Polyethylene < Copper < Tygon Important: Match the tubing to data use & reporting limits Minimize length/volume sampling train Purge before sample collection Equipment Blank: Tubing may be checked for contamination; Fill certified clean SUMMA Canister by passing analytical grade Zero Air or Nitrogen through length of tubing and submit for analysis. 19 Field Documentation Sample identification Sample location, date and time of sample collection Sampling depth (soil gas or sub-slab) Sampling height (in breathing zone or other?) Relative moisture content (dry, moist, saturated, etc.) of the sampling zone Soil type present in the sampling zone (e.g., clay, sand, gravel, etc.) Local atmospheric conditions, wind direction Sampling methods and equipment Purge volumes and equipment used Initial and final pressure of the Summa canister PID/FID measurements should be recorded d on the chain-of-custody Chain-of-Custody records Record Summa Canister & Flow controller ID s on Chain of Custody Leak Check protocol and compound used especially if a VOC is used!!! 20 Import to review data in context with information concerning all aspects of the sampling event 10

11 Field Documentation Air Chain of Custody 22 11

12 Requested Parameters Methods Volatile Organic Compounds: TO-15, TO-17, NIOSH 1501 VOCs: by Modified SW8260B or SW8021 (typically used as screening tools) Fixed Gas ASTM 1946 a.k.a. natural attenuation parameters PAHs, Semivolatiles: TO-13 (or TO-15 for Naphthalene) Petroleum Hydrocarbons: TO-15, TO-3, MA APH, NIOSH Methods 1501 & 1550, SW8015B, TO-15 PIANO, passive monitors Mercury modified NIOSH 23 TO-15 Analytical Overview For Definitive Data, TO15 is the Typical Method Cold Trap GC/MS Whole air sample Sorbent Traps 24 12

13 Vapor Intrusion Analytical Overview 2002 OSWER Draft Guidance Table 2 lists 114 Compounds of Potential Concern (COPCs) Includes VOCs, Semivolatiles & Metals TO-15 only applicable for VOCs Typical TO-15 includes ~ 65 compounds 46 of the typical compounds are included in Table 2 Some have target concentrations lower than typical TO-15 RLs ~ 68 compounds are not included in a typical TO Units Of Measure - Air One mole of gas at room temperature = liters Conversion from parts per billion volume (ppbv) to micrograms per cubic meter (ug/m 3 ) you need the molecular weight (MW). ug/m3 = ppbv x (MW/24.45) ppbv = ug/m 3 x (24.45/MW) 26 Examples: Compound MW ppbv ug/m 3 Benzene Toluene Naphthalene Trichloroethene Tetrachloroethene

14 Media Selection Summa Canister Options: 1 or 6 liter Summa canisters? Size and type may be determined by the sample duration and reporting limit needed Soil Gas 1 liter (or 6 liter) Ambient & Indoor Air; typically 6 liter Adequate volume for 24 hr temporal sample Adequate volume to meet lower RL s with full scan analysis ml aliquot is typically used for analysis For 6 Liter Cans Sampling Period (hours) Flow Rate Range (ml/min.) Collected volume is ~5 liters (flow = volume in ml / sampling time in min.). For temporal samples important to check vacuum gauge readings during sampling 27 Resource at: A Guide to Passive Air Sampling Summa Canisters Sampling Data Quality maybe compromised by ambient air entering SUMMA canister during Sampling resulting in Sample dilution. Sampling with a Summa Canister and flow controller Check Valve is fully closed, turned completely clockwise Remove dust cap from top of valve Attach flow controller, finger tighten until unable to rotate flow controller, then tighten additional 1/4-1/2 turn with the 9/16 wrench. Flow controller includes a vacuum gauge, open the canister valve counterclockwise about 1 turn The vacuum gauge should read -30 ins of mercury At the end of the sampling period, close the canister valve. Do not overtighten (the vacuum gauge should read approx 5 ins of mercury) Replace dust cap Source: Restek Complete all documentation, Chain of Custody, Canister label, record pressures & canister & Flow Controller ID s Check flow controllers during temporal sampling The vacuum gauge should move from 30 to 5 Hg +10% over the 8 or 24 hrs. Check it partway through to see that its moving appropriately. Gauges are only an indictor: Too little sample, gas will be added at the laboratory resulting in a dilution 28 14

15 Media Certification & Management Cleaning & Certification Canister & flow controller management critical as reporting limits go lower Best Practices: Canisters & flow controllers have a unique IDs and be tracked from day one! Certification of media using same method as the final analysis Canister Cleaning Evacuated, heated, pressurized w/humidified ultra clean air Media segregated for cleaning based on the canisters last use Flow Controller Cleaning and Certification Heated and purged with heated and humidified ultra clean air Flow rate set against NIST traceable flow meter, flow rate marked on back of each controller Flow rate double checked prior to shipment Critical Orifice flow controllers with all stainless steel construction Certification requirements: Batch certification the canister that had the highest levels of VOC s detected is analyzed No detections of target compounds above ½ the RL s Each canister is leak checked (must hold vacuum of ~ 30 in Hg for a minimum of 24 hours 29 Individual certification Each canister is analyzed after being cleaned and data is provided with the final data package Tedlar Bags A tool for collecting samples for on site screening Used for analysis of higher concentrations (ppm levels) for certain chemicals Drawbacks Loss of sample in during shipping Over-inflated bags can break in Air travel Under-inflated bags can arrive deflated Light sensitive compounds degrade Cross contamination of samples during shipping Should be shipped in individual containers /boxes Contaminants can migrate into and out of bags Low levels contamination in Tedlar Bags low level BTEX hits seen in some new bags. Tedlar bags should not be used for ambient or indoor air samples when looking for low reporting limits

16 Laboratory Proficiency Testing A measure of data quality & performance is proficiency testing 31 Data Quality Objectives Analyte list: May vary at every site Discuss your target list with the lab Discuss action limits and how dilutions will be handled Reporting units, ug/m 3 or ppbv (both?) Reporting Limits: Lowest standard of the instrument s initial calibration- also referred to as Practical Quantitation Limit or Detection Limit Method Detection Limits: Statistical number that is derived from 7 replicate analyses of a standard Reporting limits: 3-5 times above the calculated MDL to be valid 32 Request and review air laboratory s Standard Operating Procedures 16

17 Testing Methods & DQO s Sampling and Analytical Testing Method Selection A variety of analytical methods are available to measure air samples, all of which can give accurate results when appropriate QA/QC is included and evaluated. Criteria for Method Selection: Site or Program specific methods and/or compounds of concern Concentrations that may be encountered during sampling Published State or program specific screening tables and data use Sampling logistics & cost Data Quality Considerations: Screening vs. Definitive Data Sample containers: Tedlars, Summa Canisters, Sorbent Media DQOs may change while developing the site conceptual model and/or as information is gathered. 33 Legally Defensible Data? 34 Data Validation is a critical step: Were Data Quality Objectives met? Was the sample media in good condition and certified appropriately? Was a technically sound, proven analytical method used? If appropriate, was the laboratory accredited by NELAC and/or state and familiar with applicable guidance? Was analytical QA/QC met? Calibration, 2 nd Source Standards, Method Blanks, Blank Spikes, etc. Samples analyzed within holding time? Canisters used within shelf life? Method Detection Limits support reporting limits? 17

18 Summary Developing a Conceptual Site Model (CSM) is key in understanding the potential for inhalation exposure Communicate to the laboratory, compound list, sample type and screening/reporting levels to meet the DQO s Standard operating procedures and field documentation is vitally important t in defining i final data quality Risk & Liabilities can be significant Documentation is critical in establishing credibility of the data collected 35 EPA News EPA is considering vapor intrusion as a sole condition for listing a site for Superfund cleanup, a move that could dramatically increase the number of sites slated for federal remediation: EPA Weighs Options For Listing NPL Sites Due To Vapor Intrusion Pathway EPA is weighing options for how it could add sites to the Superfund National Priorities List (NPL) due solely to exposures from toxic vapors that escape from underground contamination sources, a new exposure pathway the agency has estimated could result in an additional 37 sites being added to the list at a time when the program lacks funds. Background reading: EPA Vows To Tighten Draft Vapor Screening Guide Ahead Of 2012 Release EPA is vowing to strengthen its 2002 draft guidelines for assessing the risks posed by toxic vapors that intrude into structures near contaminated sites, saying in a recent review of the guide that the agency will expand the list of chemicals for which parties must screen, update chemicals' toxicity data and increase the frequency of indoor air testing. EPA Plans Supplement To 5-Year Review Guide To Handle Vapor Intrusion EPA is developing supplemental Superfund guidance in order to address vapor intrusion pathways under mandatory five-year reviews of cleanup remedies because the agency is seeing an increasing number of vapor intrusion cleanup issues surface during the reviews, according to an EPA regional source. 36 Source: EPA Insider News September

19 Questions? CHRIS ANDERSON Product Manager - Air Eastern US Chris.Anderson@testamericainc.com Phone: LinkedIn: p 37 19