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Characterization and Monitoring

Our technology guides collect information about many types of technologies used to characterize and/or monitor a site before, during or after remediation work. Current initiatives related to site cleanup, websites maintained by EPA and other federal agencies and state organizations, and recent documents are also included on this page.

Technology Pages

Direct-Push Soil and Soil-Gas Samplers have been developed to collect samples of unconsolidated material and vadose-zone gases from a range of depths, without generating large volumes of cuttings. Soil-gas sampling systems analyze vadose-zone gases at the surface or permit real-time chemical monitoring of soil gases in conjunction with direct-push analytical sensors.

Direct-Push Platforms use hydraulic pressure to advance sampling devices and geotechnical and analytical sensors into the subsurface. There are two sampling modes. One uses a specific tool string that either performs downhole measurements or gathers a soil or water sample at a specific depth. In the other mode, a dual tube arrangement is used to take continuous soil samples for evaluation at the surface.

Direct-Push Geotechnical Sensors can provide information about the physical properties of the subsurface environment, for example, density, competence and thickness of layers of soil or sediment. Sensors can provide information about stratigraphy, estimate depth to groundwater or approximate hydraulic conductivity.

The relatively low cost of Direct-Push Groundwater Samplers allows the collection of a larger number of samples both horizontally and vertically than could be done using conventional rigs. This density of sample taking provides a better idea of source zone locations and contaminant plume architecture, which maximizes monitoring well placement efficiency and remedy design.

Direct-Push Membrane Interface Probes are semi-quantitative, field-screening devices that can detect volatile organic compounds (VOCs) in soil and sediment. They are used in conjunction with a direct-push platform to collect samples of vaporized compounds.

Explosives behave differently than most other organic contaminants and pose an immediate safety hazard when present in large quantities or within unexploded ordnance (UXO). Energetic materials include chemicals that are used by the military as propellants, explosives and pyrotechnics. To assess the extent of explosive contamination, it is necessary to detect and identify explosives and their degradation products in soil and groundwater.

Fiber Optic Chemical Sensors (FOCS) operate by transporting light by wavelength or intensity to provide information about analytes in the environment surrounding the sensor. The environment surrounding a FOCS is usually air or water.

Gas Chromatography (GC) is the most widely used chromatographic technique for environmental analyses, and is used onsite in field investigations and by offsite reference laboratories. Chromatography uses a diverse group of methods to separate closely related components of complex mixtures. Field GC can provide real-time, or near real-time data, facilitating decision making and reducing the length of field mobilization.

Geophysical methods measure physical properties of materials that can be used to infer information about the surface and subsurface of the Earth. These minimally invasive to non-invasive methods support the characterization and remediation of contaminated hazardous waste sites. Geophysical methods provide both quantitative and qualitative information.

High-Resolution Site Characterization (HRSC) strategies and techniques use scale-appropriate measurement and sample density to define contaminant distributions, and the physical context in which they reside, with greater certainty, supporting faster and more effective site cleanup.

Immunoassay technologies use antibodies to identify and quantify organic compounds and a limited number of metallic analytes. The technology is used widely for environmental field analysis because the antibodies can be highly specific to the target compound or group of compounds, and immunoassay kits are relatively quick and simple to use.

Infrared Spectroscopy has been an established benchtop laboratory analytical technique for many years. It identifies and quantitates compounds through the use of their infrared absorption spectra. Another use of the infrared spectra is found with video cameras that use infrared absorption to image the absorbing compounds on a video tape.

Laser-induced Fluorescence is a method for real-time, in situ field screening of residual and non-aqueous phase hydrocarbons in undisturbed vadose, capillary fringe and saturated subsurface soils and groundwater. The technology is intended to provide highly detailed, qualitative to semiquantitative information about the distribution of subsurface petroleum contamination containing polycyclic aromatic hydrocarbons (PAHs).

Mass discharge and flux estimates quantify source or plume strength at a given time and location. Consideration of the strength of a source or solute plume improves evaluation of natural attenuation and assessment of risks posed by contamination to downgradient receptors, such as supply wells or surface water bodies.

Mass Spectrometry is an established analytical technique that identifies organic compounds by measuring the mass of the compound's molecule. Although mass spectrometry can be used for the analysis of metals, non-metallic elements and radionuclides, it is most generally used for organic analysis as a field analytical technique.

Open Path Technologies: Ultra Violet-Differential Optical Absorption Spectroscopy (UV-DOAS) uses the unique absorption of specific electromagnetic energy wave lengths by chemicals in the ultra violet, visible and near infrared spectrum to identify and quantify individual chemicals.

Open Path Technologies: Open Path Fourier Transform Infrared (OP-FTIR) spectroscopy is a versatile technology that can measure the presence of many chemicals in air simultaneously and achieve relatively low detection limits. FTIR open path measurements can be made using an active or passive approach.

Open Path Technologies: LIDAR operates on the same principles as radar except that it uses light rather than radio waves to collect information. There are three generic types of LIDAR:

  • Range finders are used to determine the distance to a solid or hard target.
  • Differential absorption LIDAR (DIAL) is used to measure chemical concentrations in the atmosphere (open air).
  • Doppler LIDAR is used to measure the velocity of a moving target.

Open Path Technologies: Raman Spectroscopy sensors can identify chemicals, and provide an average concentration over the distance measured or at specified distances when a lidar configuration is used. The instrument uses an intense monochromatic light source and detectors to measure a portion of the light that is scattered inelastically from the analyte molecule.

Open Path Technologies: Tunable Diode Lasers (TDLs) are designed to focus on single absorption wavelengths specific to a compound of concern in the gaseous form. They are capable of achieving low detection limits and are virtually interferent-free. Open path TDLs are used in atmospheric pollutant studies, fenceline monitoring, process line/tank leak detection, industrial gas-purity applications and monitoring and control of combustion processes.

Passive (no purge) Samplers use methods based on the free flow of contaminant molecules from the sampled media to a receiving phase in a sampling device. Depending upon the sampler, the receiving phase can be a solvent, chemical reagent or porous adsorbent. They are deployed down a well to the desired depth within the screened interval or open borehole to obtain a discrete sample without using pumping or a purging technique.

Test Kits are self-contained analytical kits that generally use a chemical reaction that produces color to identify contaminants, both qualitatively and quantitatively. Numerous different kits are used in the environmental field. Test kits also can be used after an initial site characterization phase to monitor the conditions of a remediation system or to confirm that contaminated soils have been removed.

X-Ray Fluorescence instruments are field-portable or handheld devices for simultaneously measuring metals and other elements in various media. The handheld or field-portable units use techniques that have been developed for analysis of numerous environmental contaminants in soil and sediment. They provide data in the field that can be used to identify and characterize contaminated sites and guide remedial work, among other applications.

Technology Selection Tools

Field Sampling and Analysis Technologies Matrix and Reference Guide

This document was prepared for the U.S. Navy and the U.S. EPA. It is intended to provide comparative screening information on analytical and sampling technologies. The goal of the matrix is to ensure that project managers and site stakeholders are aware of the full-range of technology options available to them to assess and characterize contamination at their sites.

ITRC: Integrated DNAPL Site Characterization and Tools Selection (ISC-1)

Published in 2015, this document, with an on-line presence, synthesizes the knowledge of DNAPL site characterization and remediation acquired over the past several decades, and provides guidance on simultaneous characterization of contaminant distributions, hydrogeology, and attenuation processes.

SERDP ESTCP: Passive Sampling for Groundwater Monitoring: Technology Status

A summary of research on tools available to reduce the costs of long term groundwater monitoring, focusing on three types of passive samplers, including advantages, disadvantages and performance information.

ITRC: Tool Selection for the Characterization of Contamination in Fractured Bedrock

The Tool Selection Worksheet offers a rapid method of identifying the appropriate tools and information for collecting geologic, hydrologic, and chemical data. An interactive approach to evaluate over 100 investigation tools that can be used to collect the data needed to satisfy the data collection objectives.

USGS/EPA: Fractured Rock Geophysical Toolbox Method Selection Tool (FRGT-MST)

A spreadsheet-based to identify methods for use at fractured-rock sites, based on project goals and site description. It includes 30 surface, cross-hole, and borehole geophysical methods.

USGS/EPA: The Scenario Evaluator for Electrical Resistivity (SEER) Survey Pre-Modeling Tool

This resource is intended for use by practitioners who wish to determine the value of including electrical resistivity imaging to achieve project goals, and is designed to have broad utility in industry, teaching, and research.

General Technology Resources

High-Resolution Site Characterization (HRSC) Focus Area

The High-Resolution Site Characterization (HRSC) Focus Area reflects the state-of-the-science for environmental site characterization. HRSC strategies and technologies use scale-appropriate measurement and data density to delineate contaminant distributions in environmental media with greater certainty, supporting faster and more effective remedy selection, design and implementation. This website provides a description of the general concepts and benefits of HRSC and offers resources including case studies for sites where HRSC has been applied, information on practitioner forums, information on available training, and instructions on accessing available support for understanding and applying HRSC.

Strategic Environmental Research and Development Program (SERDP) and Environmental Security Technology Certification Program (ESTCP) Site Characterization, Monitoring, and Process Optimization

The Strategic Environmental Research and Development Program (SERDP) is the Department of Defense's (DoD) environmental science and technology development program, planned and executed in full partnership with the Department of Energy and the Environmental Protection Agency, with participation by numerous other federal and non-federal organizations. Many of SERDP's projects support improvements in investigating and cleaning up contaminated sites. The Environmental Security Technology Certification Program (ESTCP) is SERDP's sister program, which supports demonstration and validation of innovative, cost-effective environmental technologies.

California Environmental Technology Certification Program

Cal/EPA's certification program is a voluntary program that provides participating technology developers, manufacturers, and vendors an independent, recognized third-party evaluation of the performance of new and mature environmental technologies. Developers and manufacturers define quantitative performance claims for their technologies and provide supporting documentation; Cal/EPA reviews that information and, where necessary, conducts additional testing to verify the claims. The technologies, equipment, and products that are proven to work as claimed receive official state certification. The certification program is voluntary and self-supporting. Companies participating in the program pay the costs of evaluating and certifying their technologies.

Test Methods for Evaluating Solid Waste, Physical/Chemical Methods, SW-846

The Test Methods for Evaluating Solid Waste: Physical/Chemical Methods Compendium, also known as SW-846 or the Compendium, is EPA's official collection of methods for use in complying with the Resource Conservation and Recovery Act (RCRA) regulations. SW-846 is organized into chapters providing guidance on how to use the methods and groups of methods, called "series", which are organized by topic. The methods and chapters change over time as updates are published to keep up with evolving analytical and measurement needs. In addition to the methods that are in the official SW-846 compendium, EPA has validated methods. These methods are tested and validated by laboratories and go through extensive review, but they have not been incorporated into SW-846 through the Federal Register process. EPA encourages using the validated methods, if possible, for the most current version of a method.

Environmental Cleanup Best Management Practices: Effective Use of the Project Life Cycle Conceptual Site Model

The U.S. Environmental Protection Agency (EPA) supports the use of best management practices (BMPs) as a mechanism for maximizing technical effectiveness and resource efficiency in the execution of site assessment and cleanup projects. This fact sheet is the first in a series of documents that address conceptual site models (CSMs). This fact sheet summarizes how environmental practitioners can use CSMs to achieve, communicate, and maintain stakeholder consensus on site understanding, while satisfying the technical and quality objectives required for each stage of a cleanup project's life cycle. The focus is on defining stages and products of CSMs along with potential applications of CSMs at various stages of a project life cycle. Content herein is presented in a Superfund Program context; however, to the extent practical, text has been written to maximize applicability in other programs and regulatory frameworks. Other agencies and programs may find these concepts useful and environmental cleanup practitioners are encouraged to explore the utility and integration of a project life cycle CSM within their own program requirements and deliverable schedules.

Interstate Technology and Regulatory Council (ITRC) Incremental Sampling Methodology Team

Incremental sampling methodology (ISM) is a structured composite sampling and processing protocol for soils that provides representative samples of specific soil volumes by collecting numerous increments of soil that are combined, processed and subsampled according to specific protocols. ISM reduces data variability and improves the reliability and defensibility of sampling data.


A project is funded by ESTCP as part of their technology transfer program to develop a resource that maintains the most up-to-date information about environmental restoration technologies. Articles are written by invited experts, edited by leaders in this field, and aim to introduce and summarize current knowledge to environmental project professionals on topics using cross-linked references to reports and technical literature.

Summary of the Triad Approach to Decision-making for Hazardous Waste Sites

The Triad approach to decision-making for hazardous waste sites offers a technically defensible methodology for managing decision uncertainty that leverages innovative characterization tools and strategies. The Triad refers to three primary components, systematic planning, dynamic work strategies, and real-time measurement systems. If you are unfamiliar with the Triad, follow the links to learn more about what makes the Triad different from traditional approaches, key Triad concepts, requirements for successfully implementing a Triad approach, and the benefits one can expect from implementing the Triad.

Technical Support Resources

Superfund Analytical Services/Contract Laboratory Program (CLP)

The Superfund Contract Laboratory Program (CLP) provides analytical services to EPA, the Army Corp of Engineers as well as state, local and Tribal agencies to support Superfund, Brownfields, and other EPA programs. The analytical services section provides guidelines and information about analytical methods available from the CLP on inorganics, organics and low concentration, and non-routine analyses.

EPA Environmental Response Team Center

EPA's Environmental Response Team (ERT) provides EPA regional and headquarters offices, federal, state and local agencies, and foreign governments with experienced technical and logistical assistance in responding to environmental emergencies, such as oil or hazardous materials spills. ERT also provides assistance in the characterization and cleanup of hazardous waste sites. The (ERT) website offers an array of products to assist environmental practitioners both in the field and in the office. They offer immediate download of items such as software packages, guidance related to a wide variety of environmental sampling procedures, analytical and quality assurance standard operating procedures (SOPs), fact sheets, and bulletins.

Superfund Technical Support and Resource Centers

The Superfund Technical Support and Resource Centers host information or links to Superfund program research needs, Office of Research and Development research plans and results for Superfund, and sources of technical support for Superfund and RCRA Corrective Action program staff.

Technical Support Project for Cleaning Up Contaminated Sites

EPA established the Technical Support Project (TSP) in 1987 to provide technical assistance to regional Remedial Project Managers (RPMs), Corrective Action Staff, and On-Scene Coordinators. The TSP consists of a network of regional forums and specialized technical support centers located EPA laboratories, and the Environmental Response Team. The objectives of the TSP are to share information and best practices with other EPA programs and other federal agencies.

Email Newsletters

Newsletters on Innovative Treatment Technologies

TechDirect is an information service that highlights new publications and events of interest to site remediation and site assessment professionals. At the beginning of every month, the service, via e-mail, will distribute a message describing the availability of publications and events. For publications, the message will explain how to obtain a hard copy or how to download an electronic version.

The Technology Innovation News Survey contains market/commercialization information; reports on demonstrations, feasibility studies and research; and other news relevant to the hazardous waste community interested in technology development. This report is updated each month.

Federal Business Opportunities (FedBizOpps) contains summaries of procurement and contract award notices issued the previous week that pertain to hazardous waste, solid waste, underground storage tank remediation, and other environmental topics. However, it does not necessarily contain EVERY notice on these topics. Federal Business Opportunities (FedBizOpps) is published weekly.