U.S. EPA Contaminated Site Cleanup Information (CLU-IN)

U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

Dense Nonaqueous Phase Liquids (DNAPLs)

Detection and Site Characterization


Adobe PDF LogoDense Non-Aqueous Phase Liquids (DNAPLs): Review of Emerging Characterization and Remediation Technologies
Interstate Technology & Regulatory Council (ITRC). DNAPLs-1, 81 pp, 2000

Three general types of emerging DNAPL characterization technologies are presented in this document: geophysical techniques (non-intrusive to minimally intrusive), direct push technologies employing one or a variety of DNAPL screening/sampling devices, and in situ, large-volume chromatography using chemical tracers.

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Partitioning Interwell Tracer Technique | Radon

Partioning Interwell Tracer Technique

The following discussion is taken from Site Characterization Technologies for DNAPL Investigations, EPA 542-R-04-017Adobe PDF Logo.

The partitioning interwell tracer test (PITT) is an in situ technique for estimating the volume and percent saturation of DNAPLs in both the vadose and saturated zones.

In the vadose zone application, a line of injection wells is drilled on one side of the contaminant mass, and a second line of extraction wells is placed on the other side. Two types of tracer gases—partitioning and conservative—are introduced into the injection wells and removed from the extraction wells. The partitioning gases are chosen so that they will be slowed down at different rates by the DNAPLs they contact as they move through the soil. Conservative gases are chosen that will be minimally affected by the DNAPLs and hence travel more quickly to the extraction wells. DNAPL volumes can be calculated based on breakthrough curves for the tracers across the well line. The time frame for the actual test is in the range of one week, depending on the geology and distance between wells, but it can be much longer.

The concept is the same for the saturated zone application. Partitioning tracer chemicals are chosen that will move through the ground water and soil matrix relatively easily under pumping conditions, but will preferentially and reversibly attach themselves to DNAPLs. Conservative chemicals are chosen that will react minimally with both the natural matrix and the DNAPLs. By using the arrival times of both the partitioning and conservative chemicals in extraction wells, the amount of DNAPLs present can be estimated.

For Further Information

Adobe PDF LogoDNAPL Site Characterization Using a Partitioning Interwell Tracer Test at Site 88, Marine Corps Base Camp Lejeune, North Carolina
Naval Facilities Engineering Service Center, Port Hueneme, CA, 131 pp, 1999

A PITT was completed at Site 88, the location of the Morale, Welfare, and Recreation Dry Cleaners at the Marine Corps Base Camp Lejeune, North Carolina. The PITT was conducted to estimate the saturation, volume, and spatial distribution of tetrachloroethene that is present as a DNAPL within the selected test area. The PITT results provided characterization of the initial DNAPL conditions at the site in preparation for a surfactant-enhanced remediation demonstration to remove DNAPL from the shallow aquifer.

Adobe PDF LogoIn-Situ Characterization of Dense Non-Aqueous Phase Liquids Using Partitioning Tracers
G.A. Pope, D.C. McKinney, A.D. Gupta, R.E. Jackson, and M. Jin.
DOE/ER/14720, 219 pp, 2000

This report describes the issues involved in using partitioning tracers as well as a demonstration of using them in connection with a surfactant flood of a DNAPL.

Adobe PDF LogoPartitioning Tracers for In-Situ Measurement of Nonaqueous Phase Liquids in the Subsurface
M.L. Brusseau, et al.
DOE/ER/14722, 37 pp, Sep 2000

This project explores the use of partitioning tracer tests for the detection and quantification of NAPLs in subsurface systems, as well as the influence of factors such as physical heterogeneity, non-uniform NAPL distribution, and dilution effects on NAPL/water mass transfer. This latter issue is important with respect to both the efficacy of the partitioning tracer method and the dissolution behavior of NAPLs. Lastly, the use of gas-phase partitioning tracer tests to measure soil-water content and fluid-fluid interfacial areas is evaluated.

Adobe PDF LogoTracer Techniques for DNAPL Source Delineation and In Situ Flushing Techniques for Enhanced Source Removal: Pilot Scale Demonstrations at the Dover National Test Site
M.C. Brooks, M.D. Annable, S.C. Rao.
NTIS: ADA410848, 293 pp, Sep 2001

This report evaluates the performance of innovative tracer techniques for DNAPL characterization and in situ cosolvent and surfactant flushing for DNAPL removal in an isolated test cell (3.0m x 4.5m x 12.3m) located at the Dover National Test Site, Dover AFB, DE.

Abstracts of Journal Articles

Analysis of Partitioning Interwell Tracer Tests

Analytical Method Developments to Support Partitioning Interwell Tracer Testing

The Applicability of Dissolved Helium and Neon as Dense Nonaqueous Phase Liquid (DNAPL) Partitioning Tracers

Application of Gas-Phase Partitioning Tracer Tests to Characterize Immiscible-Liquid Contamination in the Vadose Zone Beneath a Fuel Depot

Characterization of Tetrachloroethene DNAPL in Low-Permeability Coastal Plain Sediments, North Carolina

Controlled Release, Blind Tests of DNAPL Characterization Using Partitioning Tracers

Diffusive Partitioning Tracer Test for Nonaqeous Phase Liquid (NAPL) Detection in the Vadose Zone

Effect of Mass Transfer Rate Limitations on the Use of Partitioning Tracers for the Characterization of DNAPL Micropools in the Subsurface

Evaluation of the Partition Interwell Tracer Technique for Possible Characterization of DNAPL Pools

Field Evaluation of Interfacial and Partitioning Tracers for Characterization of Effective NAPL-Water Contact Areas

Helium and Neon Groundwater Tracers to Measure Residual DNAPL: Laboratory Investigation

Influence of Residual Surfactants on DNAPL Characterization Using Partitioning Tracers

Krypton and Sulfur Hexafluoride as Non Aqueous Phase Liquid Partitioning Tracers in the Saturated Zone

Monitoring Partitioning Tracer Testing and Surfactant Flooding by In-Line Gas Chromatography Techniques

A New Paradigm in DNAPL Source Zone Characterization: 3D Imaging of Contaminant Distributions Through Hydraulic and Tracer Tomography

Non-Invasive Imaging of NAPL/Partitioning Tracer Interaction in Porous Media

Partitioning Tracer Tests as a Remediation Metric: Case Study at Naval Amphibious Base Little Creek, Virginia Beach, Virginia

Practical Applications of Tracers in Environmental Hydrogeology and Groundwater Remediation

Simulation and Performance Assessment of Partitioning Tracer Tests in Heterogeneous Aquifers

Tracer Interaction Effects during Partitioning Tracer Tests for NAPL Detection

Tracers as Tools for Design and Evaluation of Injection-Based In Situ Groundwater Remediation Systems

Design of Aquifer Remediation Systems: (1) Describing Hydraulic Structure and NAPL Architecture Using Tracers


Adobe PDF LogoRadon-222 as Natural Tracer for Monitoring the Remediation of NAPL Contamination in the Subsurface: Cost and Performance Report
Environmental Security Technology Certification Program, ESTCP Project ER-9916, 71 pp, 2008

This report describes the use of naturally occurring radon-222 as a partitioning tracer for locating and quantifying residual or pooled NAPL (e.g., chlorinated solvent) contamination in the subsurface and for monitoring changes in NAPL quantities resulting from remediation activities. The method is based on measuring radon in ground-water samples from existing monitoring wells. Two methods of using radon were evaluated at Dover National Test Site: a static method that involves the monitoring of NAPL concentrations in ground-water samples collected spatially and temporally at a site, and a dynamic method using single well push-pull tests. The most cost-effective use of the method is for monitoring the progress of NAPL contamination using the static method where ground-water samples are periodically collected and changes in radon concentration are monitored at a specific location over time.


Combination of Radon and Stable Isotope Analysis as a Tool for Decision Support Concerning the Remediation of NAPL-Contaminated Sites

Numerical Simulations of Radon as an In Situ Partitioning Tracer for NAPL Quantifying Contamination Using Push-Pull Tests

Push-Pull Partitioning Tracer Tests Using Radon-222 to Quantify Nonaqueous Phase Liquid Contamination

Radon as a Natural Partitioning Tracer for Locating and Quantifying DNAPL Saturation in the Subsurface

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