Significance and Use
4.1 NAPLs (for example, chlorinated solvents, petroleum products, and creosote) can be emplaced in sediments through a variety of mechanisms (Guide E3248). Dense non-aqueous phase liquids (DNAPLs) are more dense than water, whereas light non-aqueous phase liquids (LNAPLs) are less dense than water.
4.2 Standardized guidance and test methods currently exist for assessing NAPL mobility at upland sites, from organizations such as ASTM (Guides E2531 and E2856), Interstate Technology & Regulatory Council (1)3 and the American Petroleum Institute (2, 3).
4.3 Guide E3248 provides guidance regarding when a NAPL movement evaluation is warranted. After confirming that NAPL is present and evaluating nature and extent as appropriate, the next step in any NAPL movement evaluation is to evaluate if NAPL is mobile or immobile at the pore scale—this is done using tiered or weight of evidence (WOE) approaches. This guide provides a structured process to select samples to submit to the laboratory for NAPL mobility testing that is part of a NAPL movement evaluation.
4.4 This guide may be used by various parties involved in sediment corrective action programs, including regulatory agencies, project sponsors, environmental consultants, toxicologists, risk assessors, site remediation professionals, environmental contractors, and other stakeholders.
4.5 This guide should be used in conjunction with other reference material (refer to Section 2 and References) that direct the user in developing and implementing sediment assessment programs.
4.6 This guide is related to Guide E3163, concerning sediment analytical techniques used during sediment programs. This relates to Guide E3248, which discusses generic models for the emplacement and advection of NAPL in sediments. It is related to Guide E3268, which describes sample collection, field screening and sample handling considerations in NAPL movement evaluations. And this is related to Guide E3282, which describes evaluation metrics and frameworks to determine if NAPL is immobile or immobile at the pore scale, or if it is migrating or stable at the NAPL body scale.
4.7 This guide does not replace the need for engaging competent persons to evaluate NAPL emplacement and movement in sediments. Activities necessary to develop a conceptual site model should be conducted by persons familiar with NAPL-impacted sediment site characterization techniques, physical and chemical properties of NAPL in sediments, fate and transport processes, remediation technologies, and sediment evaluation protocols. The users of this guide should consider assembling a team of experienced project professionals with appropriate expertise to scope, plan, and execute sediment NAPL data acquisition activities.
4.8 This guide provides a framework based on overarching features and elements that should be customized by the user, based on site-specific conditions, regulatory context, and program objectives for a particular sediment site. This guide should not be used alone as a prescriptive checklist.
4.9 The user 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
Summary of the Process for Screening and Selection of Samples for Laboratory NAPL Mobility Testing
Section 6
Methods for Recording Visual Observations of Sheen and NAPL in Sediment Samples
Section 7
Methods for Performing Shake Testing of Sediment Samples
Section 8
Categorizing the Relative Presence of NAPL in Sediment
Section 9
Use of NAPL Categorization Results to Select Existing Samples or Identify Locations and Depths for Collecting Additional Undisturbed Samples for Laboratory NAPL Mobility Testing
Section 10
Other Methods to Select Samples for Laboratory NAPL Mobility Testing
Section 11
Keywords
Appendix X1
Recommended Procedure for Visually Characterizing Sediment for Sheen or NAPL Observations
Appendix X2
Recommended Procedure for a Sediment-Water Shake Test
Appendix X3
Case Study
References
Scope
1.1 This guide is designed for general application at a wide range of sediment sites where non-aqueous phase liquid (NAPL) is present or suspected to be present in the sediment. This guide describes a process to use field screening methods, specifically visual observations, and the results of shake tests, to categorize the relative amount of NAPL present in a sample. This categorization can then be utilized to select co-located sediment samples for laboratory testing to determine if the NAPL in the sample interval is mobile or immobile at the pore scale, or any other chemical or physical testing.
1.1.1 There is no current industry standard methodology to select sediment samples for laboratory NAPL mobility testing; the use of different methodologies is possible. This guide focuses on a selection process that uses visual observations and shake tests. This process has the advantage of being simple to use and, if applied in a disciplined manner, has been demonstrated to provide good results in the field.
1.2 This guide is intended to inform, complement, and support characterization and remedial efforts performed under international, federal, state, and local environmental programs but not supersede local, state, federal, or international regulations. The users of this guide should review existing information and data available for a sediment site to determine applicable regulatory agency requirements and the most appropriate entry point into and use of this guide.
1.3 ASTM International (ASTM) standard guides are not regulations; they are consensus standard guides that may be followed voluntarily to support applicable regulatory requirements. This guide may be used in conjunction with other ASTM guides developed for assessing sediment sites.
1.4 This guide does not address methods and means of sample collection (Guide E3163).
1.5 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.
1.6 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.
1.7 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.
