ASTM E3300-26
Standard Guide for Non-Aqueous Phase Liquid (NAPL) Mobility and Migration in Sediment—Factors Affecting Ebullition and Evaluating Ebullition Activity and the Associated Ebullition-Facilitated Transport of NAPL/Contaminants
| Standard number: | ASTM E3300-26 |
| Released: | 01.04.2026 |
| Status: | Active |
| Pages: | 28 |
| Section: | 11.05 |
| Keywords: | contaminant; contaminated sediment; ebullition; ebullition-facilitated NAPL/contaminant transport; NAPL; sediment; sediment corrective action; |
| ASTM number: | ASTM E3300 |
| Supersedes: | E3300-21 |
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.
1.2 Ebullition commonly occurs at sediment sites and is primarily a significant concern when there is associated ebullition-facilitated transport (EFT) of NAPL and associated contaminants (that is, NAPL/contaminants) from the sediment to the surface water column; this may result in exposure risk to humans or ecological receptors, or both.
1.3 To develop an overall conceptual site model (CSM) for a sediment site, it is important to evaluate if (and how) human and ecological receptors may be exposed to NAPL; this includes by the advective movement of NAPL in the sediment or NAPL/contaminants EFT from the sediment to the surface water column, or both.
1.3.1 Understanding the potential for NAPL/contaminants EFT from sediment to the surface water column is an important component of a CSM for a sediment site that forms a basis for (1) evaluating if (and how) human and ecological receptors may be exposed to NAPL/contaminants, and (2) evaluating remedial alternatives.
1.3.2 A robust CSM (including an understanding of the potential for NAPL/contaminants EFT from sediment to the surface water column) is needed when evaluating remedial alternatives for a sediment site. Additionally, buildup of ebullition gases may cause a structural integrity concern for engineered caps when this technology has been chosen as part of a site remedy.
1.4 This guide is designed for application at a wide range of sediment sites where NAPL is present (or is suspected to be present) and ebullition activity is also occurring.
1.4.1 The mechanisms for NAPL/contaminants EFT from sediment to the surface water column are different from advective transport of NAPL/contaminants in upland environments (due to a variety of physical, geochemical, and biological differences), thus necessitating this guide.
1.4.2 This guide addresses the processes that lead to (or influence) ebullition activity and NAPL/contaminants EFT; methods for quantifying ebullition gas and NAPL/contaminants EFT (that is, fluxes); considerations for sample timing, and sampling procedures; and the use of site data in estimating an annual NAPL/contaminants EFT loading to the surface water column at a sediment site, or a portion of a sediment site.
1.4.2.1 Gas transport from sediment to the surface water column via ebullition without NAPL/contaminants transport is possible in areas with biogenic gas generation and no (or limited) NAPL contamination of the sediment—this is discussed in this guide. Ebullition activity should be evaluated at sites where sediment capping is a potential remedial action.
1.4.3 This guide is not intended to address remediation of sediment sites where NAPL/contaminants EFT is occurring, the fate and transport of contaminants subsequent to the ebullition transport mechanism, the measurement of contaminant concentrations within the gas bubbles, the evaluation of ebullition-associated human health and ecological risks, NAPL advection in sediment, or determining the depth below the mudline where ebullition originates.
1.4.4 Evaluation of the potential for NAPL/contaminants 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 NAPL/contaminants are migrating due to EFT, sensitive receptors could be impacted and this will influence the choice and timing of any remedy selected for that area of the sediment site.
1.5 This guide is intended to serve as a stand-alone document to consider conditions that are unique to ebullition activity and NAPL/contaminants EFT, as well as to complement other guides used for CSM development at contaminated sediment sites (Guides E1689, E1739, E2081, E2531, and E3248). This guide will aid users in understanding the unique and fundamental characteristics of sediment environments that influence ebullition activity and NAPL/contaminants EFT. Understanding the site characteristics that influence ebullition activity and NAPL/contaminants EFT within the sediment column will aid in identifying specific data requirements necessary to investigate these conditions, which will enable further refinement of the CSM of the sediment site and provide a sound basis for remedy decisions.
1.6 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.
1.6.1 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.
1.7 NAPL/contaminants EFT is the primary transport mechanism that is addressed within this guide. This guide provides an overview of the unique characteristics influencing NAPL/contaminants EFT in aquatic sediment environments and approaches to evaluate ebullition gas volumes generated and flux, as well as NAPL/contaminants EFT flux and mass loading from the sediment to the surface water column.
1.7.1 This guide is not intended to provide specific guidance on sediment site risk assessment, monitoring, or remedial action.
1.7.2 Advective movement of NAPL in sediment occurs via mobility at the pore scale or migration at the NAPL body scale (or both). These are not within the scope of this guide and are addressed in Guides E3248, E3268, E3281, and E3282.
1.7.3 Processes associated with NAPL/contaminants transport due to erosion (for example, propeller wash) are not within the scope of this guide.
1.7.4 Porewater advection may facilitate transport of dissolved-phase contaminants that are NAPL constituents in the sediment to the surface water column; however, this process is not within the scope of this guide.
1.7.5 Sheens may be observed on the surface of the water body from sources other than ebullition, such as biogenic sheens, advective NAPL/contaminants transport, NAPL seeps, discharges from outfalls (for example, municipal and industrial), or vessel discharges. Identifying sources of sheens and quantifying NAPL/contaminants loading to the surface water column from sources other than those generated by NAPL/contaminants EFT is not within the scope of this guide.
1.8 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 soil; this guide also outlines a framework to be used to determine whether a NAPL Movement Assessment should be performed at a sediment site. Guide E3268 provides guidance on the collection, field screening, 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 as part of a framework to select sediment samples to be submitted for laboratory NAPL mobility testing. Guide E3282 discusses metrics (for various lines-of-evidence (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 E3447 discusses the use of cone samplers and flux chambers to measure ebullition gas or NAPL/contaminants EFT fluxes (or both); NAPL/contaminants EFT flux can be used to estimate annual NAPL/contaminants loading to the surface water body.
1.9 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.
1.10 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the users of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.11 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.