Standard Guide for NAPL Mobility and Migration in Sediments – Screening Process to Categorize Samples for Laboratory NAPL Mobility Testing

Importancia y uso:

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

 

Subcomité:

E50.04

Referida por:

E3282-22

Volúmen:

11.05

Número ICS:

13.080.01 (Soil quality and pedology in general)

Palabras clave:

contaminated sediments; field screening; laboratory NAPL mobility testing; mobility; NAPL; sediment; sediment corrective action; shake test;