Chapter IV
Soil-Gas Surveys
, Contents
Exhibits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-v
Soil-Gas Surveys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-1
Applicability Of Soil-Gas Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-2
Physical And Chemical Properties Of Hydrocarbons . . . . . . . . IV-2
Vapor Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-2
Henry’s Law Constant (Water To Vapor Partitioning) . . IV-3
Geologic Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-4
Biodegradation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-5
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-6
Active Soil-Gas Sampling Methods . . . . . . . . . . . . . . . . . . . . . . . . . . IV-7
Applications For Active Soil-Gas Sampling . . . . . . . . . . . . . . . IV-8
Active Soil-Gas Survey Design . . . . . . . . . . . . . . . . . . . . . . . . IV-8
Review Existing Site Information . . . . . . . . . . . . . . . . . . IV-8
Preliminary Measurements For Soil-Gas Sampling . . . . IV-9
Relative Soil-Air Permeability Testing . . . . . . . . IV-9
Purge Volume And Rates . . . . . . . . . . . . . . . . . . IV-9
Subsurface Short Circuiting . . . . . . . . . . . . . . . . IV-9
Initial Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-10
Sampling Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-10
Sample Spacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-10
Sample Containers . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-11
Quality Assurance/Quality Control Procedures . . . . . . IV-11
Interpretation Of Active Soil-Gas Data . . . . . . . . . . . . . . . . . . IV-12
Costs Of Active Soil-Gas Surveys . . . . . . . . . . . . . . . . . . . . . IV-13
Active Soil-Gas Survey Case Study . . . . . . . . . . . . . . . . . . . . IV-13
Site History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-13
Soil-Gas Survey Objective . . . . . . . . . . . . . . . . . . . . . IV-15
Sampling And Analytical Methods . . . . . . . . . . . . . . . . IV-15
Results And Discussion . . . . . . . . . . . . . . . . . . . . . . . IV-15
Passive Soil-Gas Sampling Methods . . . . . . . . . . . . . . . . . . . . . . . . IV-19
Applications For Passive Soil-Gas Sampling . . . . . . . . . . . . . IV-20
Passive Soil-Gas Survey Design . . . . . . . . . . . . . . . . . . . . . . IV-20
Interpretation Of Passive Soil-Gas Data . . . . . . . . . . . . . . . . IV-21
Cost Of Passive Soil-Gas Surveys . . . . . . . . . . . . . . . . . . . . IV-21
Passive Soil-Gas Survey Case Study . . . . . . . . . . . . . . . . . . IV-21
Site History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-21
Soil-Gas Survey Objectives . . . . . . . . . . . . . . . . . . . . IV-25
March 1997 IV-iii
, Sampling And Analytical Methods . . . . . . . . . . . . . . . . IV-25
Results And Discussion . . . . . . . . . . . . . . . . . . . . . . . IV-25
Comparison Of Soil-Gas Sampling Applications . . . . . . . . . . . . . . . IV-27
Passive Soil-Gas Sampling Equipment Manufacturers . . . . . . . . . . IV-28
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-29
Peer Reviewers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-31
IV-iv March 1997
, Exhibits
Number Title Page
IV-1 Vapor Pressure And Henry’s Law Constant Of Various
Organic Compounds At 20o C . . . . . . . . . . . . . . . . . . . . IV-3
IV-2 Summary Of General Active Soil-Gas
Sampling Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-6
IV-3 Active Soil-Gas Survey Site Map With Vapor Point
And Monitoring Well Locations . . . . . . . . . . . . . . . . . . IV-14
IV-4 Active Soil-Gas Survey Plot Of Total Volatiles (ppmv)
Isoconcentrations At 9 Feet . . . . . . . . . . . . . . . . . . . . IV-16
IV-5 Active Soil-Gas Survey Plot Of Total Volatiles (ppmv)
Isoconcentrations At 12 Feet . . . . . . . . . . . . . . . . . . . IV-17
IV-6 Advantages And Limitations Of Active Soil-Gas
Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-18
IV-7 Example Of Passive Soil-Gas Sampler . . . . . . . . . . . . . . . . . IV-19
IV-8 BTEX Distribution In Groundwater Based On
Monitoring Well Data (Fg/l) . . . . . . . . . . . . . . . . . . . . . IV-22
IV-9 Passive Soil-Gas Survey Results For Diesel Fuel
Constituents (ion counts of naphthalene
and alicylic hydrocarbons) . . . . . . . . . . . . . . . . . . . . . IV-23
IV-10 Passive Soil-Gas Survey Results For BTEX
(ion counts) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-24
IV-11 Advantages And Limitations Of Passive Soil-Gas
Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-26
IV-12 Applications For Active And Passive Soil-Gas Data . . . . . . . IV-27
IV-13 Passive Soil-Gas Sampling Equipment Manufacturers . . . . . IV-28
March 1997 IV-v
Soil-Gas Surveys
, Contents
Exhibits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-v
Soil-Gas Surveys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-1
Applicability Of Soil-Gas Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-2
Physical And Chemical Properties Of Hydrocarbons . . . . . . . . IV-2
Vapor Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-2
Henry’s Law Constant (Water To Vapor Partitioning) . . IV-3
Geologic Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-4
Biodegradation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-5
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-6
Active Soil-Gas Sampling Methods . . . . . . . . . . . . . . . . . . . . . . . . . . IV-7
Applications For Active Soil-Gas Sampling . . . . . . . . . . . . . . . IV-8
Active Soil-Gas Survey Design . . . . . . . . . . . . . . . . . . . . . . . . IV-8
Review Existing Site Information . . . . . . . . . . . . . . . . . . IV-8
Preliminary Measurements For Soil-Gas Sampling . . . . IV-9
Relative Soil-Air Permeability Testing . . . . . . . . IV-9
Purge Volume And Rates . . . . . . . . . . . . . . . . . . IV-9
Subsurface Short Circuiting . . . . . . . . . . . . . . . . IV-9
Initial Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-10
Sampling Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-10
Sample Spacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-10
Sample Containers . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-11
Quality Assurance/Quality Control Procedures . . . . . . IV-11
Interpretation Of Active Soil-Gas Data . . . . . . . . . . . . . . . . . . IV-12
Costs Of Active Soil-Gas Surveys . . . . . . . . . . . . . . . . . . . . . IV-13
Active Soil-Gas Survey Case Study . . . . . . . . . . . . . . . . . . . . IV-13
Site History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-13
Soil-Gas Survey Objective . . . . . . . . . . . . . . . . . . . . . IV-15
Sampling And Analytical Methods . . . . . . . . . . . . . . . . IV-15
Results And Discussion . . . . . . . . . . . . . . . . . . . . . . . IV-15
Passive Soil-Gas Sampling Methods . . . . . . . . . . . . . . . . . . . . . . . . IV-19
Applications For Passive Soil-Gas Sampling . . . . . . . . . . . . . IV-20
Passive Soil-Gas Survey Design . . . . . . . . . . . . . . . . . . . . . . IV-20
Interpretation Of Passive Soil-Gas Data . . . . . . . . . . . . . . . . IV-21
Cost Of Passive Soil-Gas Surveys . . . . . . . . . . . . . . . . . . . . IV-21
Passive Soil-Gas Survey Case Study . . . . . . . . . . . . . . . . . . IV-21
Site History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-21
Soil-Gas Survey Objectives . . . . . . . . . . . . . . . . . . . . IV-25
March 1997 IV-iii
, Sampling And Analytical Methods . . . . . . . . . . . . . . . . IV-25
Results And Discussion . . . . . . . . . . . . . . . . . . . . . . . IV-25
Comparison Of Soil-Gas Sampling Applications . . . . . . . . . . . . . . . IV-27
Passive Soil-Gas Sampling Equipment Manufacturers . . . . . . . . . . IV-28
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-29
Peer Reviewers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-31
IV-iv March 1997
, Exhibits
Number Title Page
IV-1 Vapor Pressure And Henry’s Law Constant Of Various
Organic Compounds At 20o C . . . . . . . . . . . . . . . . . . . . IV-3
IV-2 Summary Of General Active Soil-Gas
Sampling Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-6
IV-3 Active Soil-Gas Survey Site Map With Vapor Point
And Monitoring Well Locations . . . . . . . . . . . . . . . . . . IV-14
IV-4 Active Soil-Gas Survey Plot Of Total Volatiles (ppmv)
Isoconcentrations At 9 Feet . . . . . . . . . . . . . . . . . . . . IV-16
IV-5 Active Soil-Gas Survey Plot Of Total Volatiles (ppmv)
Isoconcentrations At 12 Feet . . . . . . . . . . . . . . . . . . . IV-17
IV-6 Advantages And Limitations Of Active Soil-Gas
Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-18
IV-7 Example Of Passive Soil-Gas Sampler . . . . . . . . . . . . . . . . . IV-19
IV-8 BTEX Distribution In Groundwater Based On
Monitoring Well Data (Fg/l) . . . . . . . . . . . . . . . . . . . . . IV-22
IV-9 Passive Soil-Gas Survey Results For Diesel Fuel
Constituents (ion counts of naphthalene
and alicylic hydrocarbons) . . . . . . . . . . . . . . . . . . . . . IV-23
IV-10 Passive Soil-Gas Survey Results For BTEX
(ion counts) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-24
IV-11 Advantages And Limitations Of Passive Soil-Gas
Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-26
IV-12 Applications For Active And Passive Soil-Gas Data . . . . . . . IV-27
IV-13 Passive Soil-Gas Sampling Equipment Manufacturers . . . . . IV-28
March 1997 IV-v
