Standard
Active
Last Updated: Aug 01, 2025
Track Document
ASTM E3248-25
Standard Guide for Non-Aqueous Phase Liquid (NAPL) Mobility and Migration in Sediment—Conceptual Models for NAPL Emplacement and Influence on NAPL Movement
Standard Guide for Non-Aqueous Phase Liquid (NAPL) Mobility and Migration in Sediment—Conceptual Models for NAPL Emplacement and Influence on NAPL Movement
E3248-25
ASTM|E3248-25|en-US
Standard Guide for Non-Aqueous Phase Liquid (NAPL) Mobility and Migration in Sediment—Conceptual Models for NAPL Emplacement and Influence on NAPL Movement
Standard
E3248 Standard Guide for Non-Aqueous Phase Liquid (NAPL) Mobility and Migration in Sediment—Conceptual Models for NAPL Emplacement and Influence on NAPL Movement>
new
BOS Vol. 11.05 Committee E50
$
104.00
In stock
ASTM International
Significance and Use
4.1 Intended Users:
4.1.1 This guide may be used by various parties involved in programs evaluating the movement of NAPL in sediment, including regulatory agencies, project sponsors, environmental consultants, risk assessors, site remediation professionals, environmental contractors, analytical testing laboratories, data reviewers and users, and other stakeholders, which may include (but are not limited to) owners, buyers, developers, lenders, insurers, government agencies, and community members and groups.
4.1.1.1 This guide does not replace the need for engaging competent persons to evaluate NAPL emplacement and movement in sediment. Activities necessary to develop a CSM should be conducted by persons familiar with NAPL-impacted sediment site characterization techniques, physical and chemical properties of NAPL in sediment, fate and transport processes, remediation technologies, and sediment evaluation protocols. Users of this guide should consider assembling a team of experienced professionals with appropriate expertise to scope, plan, and execute sediment NAPL data acquisition activities.
4.2 Reference Materials:
4.2.1 This guide should be used in conjunction with other ASTM guides listed in 2.1 (especially Guides E3268, E3281, and E3282), as well as the material in the References section.
4.2.2 This guide is intended to supplement the CSM developed for the sediment site according to the principles outlined for the contaminated sites CSM Guide E1689, the guide for developing a CSM for LNAPL sites (Guide E2531), and the Risk-Based Corrective Action (RBCA) Guides E1739 and E2081, by considering conditions for NAPL emplacement and advective movement that are unique to a sediment environment. Guide E3240 discusses elements of the CSM and RBCA framework that are specific to contaminated sediment sites.
4.3 Flexible Site-Specific Implementation:
4.3.1 This guide supports users in understanding the potential emplacement and transport mechanisms for NAPL in sediment. This is an important element of an overall CSM that forms a basis for (1) investigating the nature and extent of NAPL, (2) evaluating whether (and how) human and ecological receptors may be exposed to NAPL, and (3) assessing potential remedial alternatives for NAPL.
4.3.2 Demonstrating the potential for movement of NAPL in sediment to regulators and other stakeholders has been historically hampered by the lack of standardized terminology and characterization protocols. The complexity of NAPL movement in sediment, and the lack of agreed upon methods for analysis and interpretation of site data, has led to uncertainty in corrective action decision making, which has sometimes resulted in unrealistic expectations about remedial outcomes.
4.3.3 The emplacement and transport mechanisms for NAPL in sediment are different from those in upland environments, due to a variety of physical, geochemical, and biological differences between sediment and upland environments (see Section 5), thus necessitating this guide. This guide provides conceptual models for NAPL emplacement in sediment. This guide also provides a NAPL movement evaluation framework to categorize the NAPL as being either mobile or immobile at the pore scale or migrating or stable at the NAPL body scale.
4.4 Regulatory Frameworks:
4.4.1 This guide is to inform, complement, and support (but not supersede) the requirements or guidelines established by local, state, tribal, federal, or international agencies. As such, this guide does not provide a detailed discussion of the requirements or guidance associated with any of these jurisdictions, nor is it intended to supersede applicable regulations and guidance. Users of this guide will need to be aware of (and comply with) the regulatory requirements and guidance in the jurisdiction where the work is being performed.
4.4.2 This guide may be used to support existing regulatory decision frameworks for the evaluation of NAPL mobility and migration in sediment.
4.5 Systematic Project Planning and Scoping Process:
4.5.1 When applying this guide, users should undertake a systematic project planning and scoping process to collect information to assist in making site-specific, user-defined decisions for a particular project, including assembling an experienced team of project professionals. These practitioners should have the appropriate expertise to scope, plan, and execute a sediment corrective action program. This team may include (but is not limited to) the personnel outlined in 4.1.1.
4.6 Stakeholder Engagement:
4.6.1 Users of this guide are encouraged to engage key stakeholders early and often in the project planning and scoping process, especially regulators, project sponsors, and service providers. A concerted, ongoing effort should be made by users to continually engage regulators and other relevant stakeholders as the project progresses to gain insight, technical support, and input for resolving technical issues and challenges that may arise during project implementation.
4.7 Other Considerations:
4.7.1 This guide summarizes the unique characteristics influencing the presence and potential movement of NAPL in aquatic sediment environments, but this guide is not intended to provide specific guidance on sediment site investigation, risk assessment, monitoring, or remedial action.
4.7.2 For the purposes of this guide, sediment is considered a saturated material that is below a surface water body (3.1.6), whereas soil is considered a saturated or unsaturated unconsolidated material below the upland ground surface (3.2.13).
4.8 Structure and Components of This Guide:
4.8.1 Users of this guide should review the overall structure and components of this guide before proceeding with use, including:
| Section | Title |
| Section 1 | Scope |
| Section 2 | Referenced Documents |
| Section 3 | Terminology |
| Section 4 | Significance and Use |
| Section 5 | Unique Aspects of Sediment Sites |
| Section 6 | NAPL Emplacement Mechanisms |
| Section 7 | NAPL Movement Assessment Framework |
| Section 8 | Keywords |
| Appendix X1 | NAPL Emplacement Conceptual Models |
| Appendix X2 | Sedimentary Processes and Groundwater–Surface Water Interactions |
| Appendix X3 | NAPL Movement Terminology |
Scope
1.1 This guide is designed for application at a wide range of sediment sites where non-aqueous phase liquid (NAPL) is present or suspected to be present. This guide describes emplacement mechanisms that can result in NAPL presence within sediment and how the characteristics of the sediment, aquatic environment, and NAPL will influence NAPL movement (that is, NAPL mobility, NAPL migration, or both) within sediment. This guide provides example conceptual models for NAPL emplacement in sediment to establish a common evaluation framework that can be used to assess conditions influencing NAPL movement by advection in sediment. This evaluation framework for advective NAPL movement categorizes the NAPL as being either mobile or immobile at the pore scale, or migrating or stable at the NAPL body scale.
1.1.1 Evaluation of the potential for NAPL to move in sediment is important for several reasons, including (but not limited to) the evaluation of risk to potential receptors, determining the need for potential remedial action, and developing potential remedial strategies. For example, if the NAPL is migrating, sensitive receptors could be impacted and this will influence the choice and timing of any remedy selected for an area of the sediment site. If the NAPL is immobile at the pore scale or is stable at the NAPL body scale, then remedial actions (other than to address dissolved-phase contaminants solubilized from the NAPL) may not be warranted to address this immobile or stable NAPL.
1.2 The conceptual models for NAPL emplacement in sediment presented in this guide are a component of the overall Conceptual Site Model (CSM) of the sediment site. A robust CSM is typically needed to optimize potential future work efforts at a sediment site, which may include various risk management and remedial strategies for the site, as well as subsequent monitoring after remedy implementation.
1.3 This guide discusses three broad categories of NAPL emplacement mechanisms.
1.3.1 The first category is the migration of NAPL by advection (flow through the soil pore network) from an upland site into the pore network of sediment beneath an adjacent water body. This NAPL emplacement most commonly occurs within coarser-grained strata within the sediment column.
1.3.2 The second category is the direct discharge of light non-aqueous phase liquid (LNAPL) into a water body, where it is broken down by mechanical energy to form LNAPL droplets. Oil-particle aggregates (OPAs) are formed in the water column when suspended particulates in the surface water adhere to (or penetrate into) the LNAPL droplets originating from direct discharge to the water body. Once enough particulates have adhered to (or penetrated into) an LNAPL droplet and the OPA becomes denser than the surrounding surface water, it settles through the water column onto a competent sediment surface; here, it forms an in situ deposited NAPL (IDN) and it may be buried by future sedimentation. Because the LNAPL is emplaced by the deposition of the OPAs and LNAPL releases can occur at any time, the LNAPL can be emplaced throughout the sediment column, in both finer- and coarser-grained strata.
1.3.3 The third category is dense non-aqueous phase liquid (DNAPL) flow. This is direct discharge of DNAPL into a water body, followed by settling through the water column and deposition directly onto a relatively competent sediment surface, where it may be buried by future sedimentation. The DNAPL typically experiences gravity flow atop the sediment surface, until it collects in a local sedimentary depression. Unlike the other two emplacement categories, it is the DNAPL that is the matrix and it contains entrained sediment particulates. As DNAPL releases can occur at any time, the DNAPL can be emplaced throughout the sediment column, in both finer- and coarser-grained strata.
1.4 This guide concerns the advective movement of NAPL in sediment. Ebullition-facilitated transport of NAPL from the sediment into the water column by gas bubbles is not within the scope of this guide. The measurement and evaluation of ebullition and associated NAPL/contaminant transport are discussed in Guides E3300 and E3447. Processes associated with NAPL movement due to erosion (for example, caused by propeller wash) are also beyond the scope of this guide.
1.5 Petroleum hydrocarbon, coal tar, and other tar NAPLs (including fuels, oils, and creosote) are the primary focus of this guide. These forms of contamination are commonly related to historical operations at petroleum refineries, petroleum distribution terminals, manufactured gas plants (MGPs), and various large industrial sites.
1.5.1 Although certain technical aspects of this guide apply to other NAPLs (for example, DNAPLs such as chlorinated hydrocarbon solvents), this guide does not completely address the additional complexities of those DNAPLs.
1.6 Related ASTM Standards—This guide is related to several other guides that cover various aspects of NAPL mobility and migration in sediment. Guide E3268 provides guidance on the collection and handling of sediment samples that are representative of in situ conditions for laboratory geotechnical and NAPL mobility testing. Guide E3281 discusses the use of field screening methodologies to select sediment samples to be submitted for laboratory NAPL mobility testing. Guide E3282 discusses metrics (for various lines-of-evidence (LOE)) to evaluate whether NAPL is mobile or immobile at the pore scale and, if the NAPL is mobile, describes other metrics (using additional LOE) to evaluate whether NAPL is migrating or stable at the NAPL body scale. Guide E3282 also presents example decision analysis frameworks for ascertaining whether NAPL is mobile at the pore scale or migrating at the NAPL body scale (or both). Guide E3300 discusses ebullition fundamentals and how to obtain ebullition-facilitated transport (EFT) rates for NAPL and associated contaminants (which can be used to estimate NAPL/contaminant loadings to the water body). Guide E3447 discusses the use of flux chambers to obtain the data used to calculate EFT rates.
1.7 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.
1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of users of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.