analytical methods for air and vapor sampling andy...
TRANSCRIPT
Analytical Methods for Air and Vapor
Sampling
Andy Rezendes
Alpha Analytical Labs
Andy Rezendes, Alpha Analytical, Inc.
October 11, 2011
EBC SubSlab Mitigation
Systems for Vapor Intrusion
Analytical Methods for Air and Vapor
Sampling
www.alphalab.com
Synopsis:
♦ General Overview of Air Analytical Methods
♦ Sampling Soil Vapor and Ambient Air w/ Canisters
♦ Regional Sampling Procedures for VI Investigations-
♦ MA, CT, NH, ME
♦ Your questions…
Analytical Methods for Air and Vapor Sampling
www.alphalab.com
Principle of Air Sampling
• Air sampling is conducted by creating a controlled pressure differential via mechanical means to
allow air flow into or through a collection device
Whole air sample
collect air sample in container, return to lab
Sorbent sample collect compounds of concern using solid or liquid media, return to lab
www.alphalab.com
Air Analysis Methodology
EPA Compendium of Methods (TO methods)
Source test methods-40 CFR part 60 app. A
NIOSH / OSHA methods-designed for PELs
IP methods (indoor air)
MA DEP APH method (Air-phase Petroleum
Hydrocarbons)
www.alphalab.com
Air Sampling Equipment
Canisters (FSL and SUMMA),
Tedlar bags, tubes, or badges for
VOCs
MCE or PVC cartridges for dust
and inorganics
PUF cartridges for semivolatile
organics
www.alphalab.com
grab filter F.C. w/ soil vapor
config. ambient air F.C.
2.7 Liter
• Flow controller configurations
• Canisters
• does size matter?
Air Sampling Equipment for
Canister Sampling
6.0 Liter 1.0 Liter
Smaller sizes are being
produced (i.e. 100 mL)
www.alphalab.com
• Correct configuration of flow controllers-soil vapor or ambient?
• Canister vacuum should be at 30 in.-check w/ flow controller or vacuum gauge
• Chain of custody-record can ID and flow controller serial # for your benefit!!
• Record start-stop vacuum readings
Canister Sampling Documentation
www.alphalab.com
Canister Sampling Documentation
COC Review
www.alphalab.com
• Typically composite or time weighted average (TWA)
• Duration should reflect the exposure scenario
• Grab sample only if odors are an issue
• Must be sampled through 2 micron particulate filter
• Field duplicates obtained by co-locating canisters
General Principles
Ambient Air Sampling
www.alphalab.com
• Maximum flowrate = 200 mL/min
• Use Teflon or polypropylene tubing to connect to soil gas
probe, check w/ lab for size (typically ¼” OD)
• Must be sampled through 2 micron particulate filter
!!!!
• Field duplicate sampling an issue; tee-off co-locate?
• Provide screening data on COC if available
General Principles
Soil Vapor Sampling
www.alphalab.com
• Ambient air samples –should have some vacuum left in canister (i.e. 5 in. Hg) – more critical if not
• Soil vapor samples –should have some vacuum left in canister (i.e. 5 in. Hg) – less critical if not
• Grab samples – final vacuum not critical, can go to 0 in. Hg
• Greater than 15 in. Hg – may be a need for dilution
Post – Sampling, when am I done?
www.alphalab.com
Compound Typical
Concentration
Chloromethane 0.5 ppbV / 1.03 ug/m3
CH4 + Cl2 UV
CH3Cl + HCl
Dichlorodifluoromethane
0.5 ppbV / 2.5 ug/m3
Petroleum / Combustion-related
compounds
Benzene = 0.1 ppbV / 0.32 ug/m3
Carbon Tetrachloride (10-6 = 0.16 ug/m3)
0.1 ppbV / 0.63 ug/m3
Atmospheric Background of VOCs
www.alphalab.com
Subslab Mitigation Systems and
PVC Cement
Ingredient Percent
Acetone 10-20
2-Butanone 0-5
Cylcohexanone 10-16
Tetrahydrofuran 50-60
Polyvinylchloride (PVC) 12-18
Regional Sampling Procedures MA MCP, CT, NH, ME
www.alphalab.com
MADEP Vapor Intrusion Guidance WSC# (DRAFT)
Main document
Assesment Mitigation Regulator Framework
Communication & Public Involvement Obtaining Access
•Appendix 1 –Threshold Values
•Residential – TVr
•Industrial/Commercial – TVi/c
•Appendix 2 –Soil Gas Screening Values – currenlty reserved (0.05 attenuation factor)
•Appendix 3 –Detailed Sampling Procedures
•Appendix 4 – Common GW and Soil Remidiation Approaches-reserved
•Appendix 5- Guidance on the Design, Installation, Operation, and Monitoring of Sub-
Slab Depressurization Systems
•Appendix 6 - References for Other Active Mitigation Systems
•Appendix 7 - Mitigation System Check List
•Appendix 8 -Use of Activity and Use Limitations (AULs) to Address Future Buildings
in Areas of Potential Vapor Intrusion
www.alphalab.com
Parameter Most Conservative Conditions Least Conservative
Conditions
Season Late winter/early spring Summer
Temperature Indoor 10oF > than outdoors Indoor temp < outdoor temp.
Wind Steady, > ~5 mph Calm
Soil Saturated with rain Dry
Doors/Windows Closed Open
Heating System Operating Off
MADEP Guidance-Sampling Indoor
Air
When to sample (table 2-3)
Sampling composite times (recommended) –
Commercial – 8 hr
Residential – 24 hr (minimum of 4 hr)
www.alphalab.com
Outdoor air sample recommended
Can limit investigation to COCs, refer to MassDEP Risk
Characterization Guidance (sect. 2)
Should be sampled simultaneously or at a similar time as
subslab/soil vapor samples
Other collection devices allowed in App. 3 (vials, bags,
passive monitors, tubes), no MCP methodology for these
devices
MADEP Guidance-Sampling
Indoor Air
www.alphalab.com
Currently main document not consistent w/ appendices
Should not be sampled “at too high a rate”, will most likely
be updated to 200 mL/min
Should be sampled simultaneously or at a similar time as
indoor air samples
MADEP Guidance-Sampling
Subslab/Soil Vapor
www.alphalab.com
• “Hybrid method” of TO-15 and VPH methods
• Method has been finalized (December 2009)
• Labs will not be subtracting out “non-petroleum
hydrocarbons” unless requested
• 2-Methylnaphthalene dropped from TAL
MADEP APH
(Air-phase Petroleum Hydrocarbons)-Update
www.alphalab.com
CAM Methods for TO-15 and
APH
• Question E – APH & TO-15 Methods – was the complete TAL reported for each method?
• Lab reporting requirements – Sample results
– Method Blank
– LCS
– Matrix duplicate
– Internal standard performance
– Media certification results
– Flow controller calibration results
– Vacuum of canister at receipt in lab
www.alphalab.com
CAM Methods for TO-15
and APH
• Data User (that’s you) Reporting Requirements
– Serial # of canister for each sample ID
– Serial # of flow controller for each sample ID
– Sample duration
www.alphalab.com
• Screening values for residential and commercial sites
• Specific target analyte list and RLs (Table 1)
• Soil gas sampling – maximum flowrate of 200 mL/min
• Ambient air sampling – 8 hr. or 24 hr. composite (commercial / residential)
• Living space closest to VI pathway
NHDES Vapor Intrusion Guidance Manual
www.alphalab.com
• Does not address sampling
• Has specific target analyte list and limits for soil vapor, indoor air
– Residential
– Commercial
• References EPA Vapor Intrusion Guidance
• Currently working on new guidance
CT & RI RSR Criteria
www.alphalab.com
• New guidance out, January 2010 (sampling guidance is draft)
• Has screening values for following:
– Residential – chronic & subchronic (7 yr), both single and multi-component
– Commercial – chronic & subchronic (7 yr), both single and multi-component
• Indoor air sampling duration: 24 hr. residential, 8 hr. commercial
• Soil vapor samples – 30 minute duration
• Has adopted APH method for petroleum-related sites
Maine Vapor Intrusion Guidance