ASTM E3268-25
Preview
Summary
1.1 Many contaminants (such as petroleum products and coal tar) are emplaced in sediment in the form of an immiscible liquid, known as a non-aqueous phase liquid (NAPL). NAPL can either be a light non-aqueous phase liquid (LNAPL) that is less dense than water or a dense non-aqueous phase liquid (DNAPL) that is denser than water. To develop an overall conceptual site model (CSM) for a sediment site, it is important to (1) investigate the nature and extent of NAPL in the sediment, and (2) evaluate if (and how) human and ecological receptors may be exposed to NAPL (such as by the advective movement of the NAPL in the sediment).
1.1.1 A robust CSM (including an understanding of potential NAPL movement in sediment) is needed when assessing remedial alternatives for the sediment site.
1.2 This guide is applicable for a wide range of sediment sites where NAPL is present or suspected to be present. The conditions affecting NAPL emplacement and movement in sediment are typically significantly different than in upland soils (Guide E3248).
1.3 Understanding the movement of NAPL in sediment was historically complicated by the lack of standardized protocols for characterizing NAPL movement in the diverse range of sediment environments. Any NAPL movement evaluation approaches historically used were site-specific in nature, but no common methods or decision-making frameworks were available to consistently use at various sediment sites. To address these issues, this guide and three associated guides (Guides E3248, E3281, and E3282) addressing the advective movement of NAPL in sediment have been developed.
1.4 This guide describes sample collection, sample field screening, and sample handling of sediment containing NAPL to assist in data collection to evaluate NAPL movement in sediment and to characterize the presence and extent of NAPL in the sediment.
1.4.1 This guide is applicable at sediment sites where the presence or suspected presence of NAPL has been identified in sediment.
1.4.2 This guide supports sample collection, sample field screening, and handling of sediment samples (including the shipment of these samples to the laboratory for NAPL mobility and geotechnical testing) to evaluate NAPL movement in NAPL-impacted sediment.
1.5 The goal of this guide is to provide a technical framework for sample collection, sample field screening, and sample handling activities used when collecting sediment samples to evaluate NAPL conditions, in particular NAPL movement (that is, NAPL mobility at the pore scale and NAPL migration at the NAPL body scale) in sediment using a multiple lines of evidence (LOEs) approach (Guide E3282). The results of NAPL movement assessments (Guide E3248) can be used to inform the development and selection of remedial options and post-remedial monitoring activities.
1.6 This guide discusses direct sample collection methods (that is, core and grab samples) and indirect investigation methods (that is, DART® systems,2 laser-induced florescence (LIF) methodologies, and porewater samplers) for assessing NAPL presence or absence in sediment.
1.7 This guide discusses field screening methods to assess NAPL-impacted sediment including visual observations, stratification observation, sediment-water shake tests, ultraviolet (UV) light, NAPL FLUTeTM3 and organic vapor monitor (OVM) screening.
1.8 This guide discusses sample handling considerations to obtain sediment samples representative of in situ conditions. This includes methods used to deploy and retrieve the sediment sampling device, evaluate sediment sample acceptability and integrity, characterize core sample recovery, identify samples, temporarily store samples for later processing, cut cores, remove samples from the sampling device, and freeze or cool sediment samples. Methods to be used will depend on site-specific considerations.
1.8.1 This guide discusses the objectives, approaches, and materials used for storing and transporting NAPL-impacted sediment samples, focusing on samples taken for laboratory NAPL mobility and geotechnical testing. Considerations include sample packaging and handling, storage temperature, and hold times.
1.9 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, and various large industrial sites.
1.9.1 Although certain technical aspects of this guide apply to other NAPLs (for example, DNAPLs such as chlorinated hydrocarbon solvents), this guide may not completely address all additional complexities of these other NAPLs.
1.10 Related ASTM Standards—This guide is related to several other guides that cover various aspects of NAPL mobility and migration in sediment. Guide E3248 provides guidance on NAPL emplacement mechanisms in sediment and the differences between NAPL in sediment and upland soils; this guide also outlines a framework to be used to determine whether a NAPL Movement Assessment should be performed at a sediment site. Guide E3281 discusses the use of field screening methodologies as part of a framework to select sediment samples to be submitted for laboratory NAPL mobility testing. Guide E3282 discusses metrics (for various LOEs) to evaluate whether NAPL is mobile or immobile at the pore scale and (if the NAPL is mobile) describes other metrics (using additional LOEs) to evaluate whether NAPL is migrating or stable at the NAPL body scale. Guide E3282 also presents example decision analysis frameworks for ascertaining if NAPL is mobile at the pore scale or migrating at the NAPL body scale (or both). Guide E3300 discusses ebullition fundamentals and how to measure ebullition-facilitated transport (EFT) fluxes for NAPL and associated contaminants (which can be used to estimate NAPL/contaminant loadings to the surface water body). Guide E3447 discusses the use of flux chambers to measure EFT fluxes and estimate NAPL/contaminant loadings to the water body.
1.11 Units—The values stated in SI or CGS units are to be regarded as the standard. No other units of measurement are included in this standard.
1.12 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.13 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.
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, 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.
4.1.2 This guide does not replace the need for engaging competent persons to collect, field screen, and handle sediment samples for use in the evaluation of NAPL mobility and migration in sediment. Activities described in this guide should be conducted by persons familiar with NAPL-impacted sediment site characterization techniques, as well as sediment NAPL movement assessment protocols. The users of this guide should consider assembling a team of experienced professionals (4.1.1) 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 E3248, E3281, and E3282), as well as the material in the References section.
4.3 Flexible Site-Specific Implementation:
4.3.1 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 historical lack of agreed upon methods for analyzing and interpreting site data, have led to uncertainty in corrective action decision-making, which has sometimes resulted in misleading expectations about remedial outcomes.
4.3.2 Assessment of NAPL movement in sediment is an evolving science. This guide provides a systematic, yet flexible, guidance on sample collection, sample field screening, and sample handling to accommodate variations in approaches by regulatory agencies and users, based on project objectives, site complexity, unique site features, programmatic and regulatory requirements, newly developed guidance, newly published scientific research, use of alternative scientifically based methods and procedures, changes in regulatory criteria, advances in scientific knowledge and technical capability, multiple LOEs approach, and unforeseen circumstances.
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 requirements or guidelines for collecting, field screening, and handling sediment samples used to evaluate 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 Importance of NAPL Movement Assessments:
4.7.1 The movement (or lack of movement) of NAPL in sediment is a key factor in developing protective remedial options for NAPL-impacted sediment and for the long-term management of sediment sites. Typical exposure pathways that are addressed through risk management decisions at upland sites are usually not applicable to sediment sites. Rather, “contaminants in the biologically active layer of the surface sediment at a site often drive exposure,” (1)6 because in aquatic environments, benthic organisms live in the surface sediment to maintain access to oxygenated overlying surface water. NAPL that is present in subsurface sediment below the biologically active zone (BAZ) that is not migrating (that is, NAPL that is stable at the NAPL body scale) and has overlying sediment that is expected to remain in place (that is, the sediment will not be dredged or eroded) typically does not pose a risk to human or ecological receptors, because there is no pathway for exposure other than transport of dissolved-phase contaminants from the buried NAPL source to the BAZ. Removal of stable NAPL may not be warranted during remedial actions if (1) risks from dissolved-phase contaminants originating from this stable NAPL have been evaluated and found to be acceptable or (2) unacceptable risks from the dissolved-phase contaminants can be adequately mitigated (such as by the placement of an amended cap). Thus, understanding NAPL presence, extent, and potential movement is a key factor in managing contaminated sediment sites.
4.8 Application of This Guide:
4.8.1 The use of this guide is consistent with the sediment risk-based corrective action (RBCA) process (Guide E3240) that guides users to acquire and evaluate appropriate data and use each piece of data to refine goals, objectives, receptors, exposure pathways, and the CSM. As the sediment RBCA process proceeds, data and conclusions reached at each stage help to focus subsequent evaluations. This integrated process results in efficient, cost-effective decision-making and timely, appropriate response actions for NAPL-impacted sediment. This guide is not intended to provide specific guidance on sediment site risk assessment, monitoring, or remedial action.
4.9 Structure and Components of This Guide:
4.9.1 Users of this guide should review the overall structure and components of this guide before proceeding with use, including:
Section 1 - Scope
Section 2 - Referenced Documents
Section 3 - Terminology
Section 4 - Significance and Use
Section 5 - NAPL Mobility Field Investigation Overview
Section 6 - Sediment Sample Collection Methods
Section 7 - Sediment Sample Field Screening Methods
Section 8 - Sediment Sample Handling, Storage, and Transport Methods
Section 9 - Keywords
Appendix X1 - Additional Sediment Sample Collection Considerations
Appendix X2 - Case Study
References
Technical characteristics
| Publisher | American Society for Testing and Materials (ASTM International) |
| Publication Date | 12/01/2025 |
| Collection | |
| Page Count | 20 |
| Themes | Soil quality and pedology in general |
| EAN | --- |
| ISBN | --- |
| Weight (in grams) | --- |
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