ASTM E3361-22
(Guide)Standard Guide for Estimating Natural Attenuation Rates for Non-Aqueous Phase Liquids in the Subsurface
Standard Guide for Estimating Natural Attenuation Rates for Non-Aqueous Phase Liquids in the Subsurface
SIGNIFICANCE AND USE
4.1 Guidance on management of NAPL sites and a large body of research effort contributing to their development (for example, ITRC 2018 (1); CRC CARE 2018 (2); CL:AIRE 2019 (3) and CRC CARE 2020 (4)) point to the significance of natural attenuation and NSZD in the evolution of NAPL source and the resulting distributions of COCs in soil, groundwater and vapor.
4.2 Examples of reported ranges in estimated natural attenuation rates are 300 – 7700 gallons of NAPL/acre/year (Garg et al. 2017 (5)); and 0.4 – 280 metric tons of NAPL/year (CRC CARE 2020 (4)).
4.3 The intent of this guide is to provide a standardized approach for the estimation of natural attenuation rates for NAPL in the subsurface. The rates can be used for establishing a baseline metric for those involved in the remedial decision-making process. There is a need for a systematic approach and refinement in data collection and interpretation for quantifying the spatially and temporally variable rates. Providing quality assurance in estimation of this metric will enable the assessment of relatively more engineered remedies as compared to natural remedies or MNA (Fig. 1), as well as estimation of the remediation timeframe. This comparison, when performed through a standardized approach, can lead to actionable metrics for transition to sustainable remedies through well-defined and transparent criteria. In the context of a spectrum of remediation options in terms of engineered and natural remedies (Fig. 1), the transition is from a relatively more engineered (or active remediation) to a relatively more nature-based remedy. When considered in the remedial decision-making process, estimates of natural attenuation rates can be used:
4.3.1 Before active remediation (as baseline to assess whether active remediation is needed);
4.3.2 During active remediation (as performance/optimization metric); and
4.3.3 At the end of active remediation (support transition to MNA or site closure).
4.4 Since natural ...
SCOPE
1.1 This is a guide for determining the appropriate method or combination of methods for the estimation of natural attenuation or depletion rates at sites with non-aqueous phase liquid (NAPL) contamination in the subsurface. This guide builds on a number of existing guidance documents worldwide and incorporates the advances in methods for estimating the natural attenuation rates.
1.2 The guide is focused on hydrocarbon chemicals of concern (COCs) that include petroleum hydrocarbons derived from crude oil (for example, motor fuels, jet oils, lubricants, petroleum solvents, and used oils) and other hydrocarbon NAPLs (for example, creosote and coal tars). While much of what is discussed may be relevant to other organic chemicals, the applicability of the standard to other NAPLs, like chlorinated solvents or polychlorinated biphenyls (PCBs), is not included in this guide.
1.3 This guide is intended to evaluate the role of NAPL natural attenuation towards reaching the remedial objectives and/or performance goals at a specific site; and the selection of an appropriate remedy, including remediation through monitoring of natural or enhanced attenuation, or the remedy transition to natural mechanisms. While the evaluation can support some aspects of site characterization, the development of the conceptual site model and risk assessment, it is not intended to replace risk assessment and mitigation, such as addressing potential impact to human health or environment, or need for source control.
1.4 Estimation of NAPL natural attenuation rates in the subsurface relies on indirect measurements of environmental indicators and their variation in time and space. Available methods described in this standard are based on evaluation of biogeochemical reactions and physical transport processes combined with data analysis to infer and quantify the natural attenuation rates for NAPL present in the vadose and/or saturated zones.
1.5...
General Information
Standards Content (Sample)
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.
Designation: E3361 − 22
Standard Guide for
Estimating Natural Attenuation Rates for Non-Aqueous
1
Phase Liquids in the Subsurface
This standard is issued under the fixed designation E3361; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.5 Therateestimatescanbeusedfordevelopingmetricsin
the corrective action decision framework, complementing the
1.1 This is a guide for determining the appropriate method
LNAPL Conceptual Site Model (LCSM) (Guide E2531).
or combination of methods for the estimation of natural
attenuation or depletion rates at sites with non-aqueous phase 1.6 The emphasis in this guide is on the selection and
liquid (NAPL) contamination in the subsurface. This guide application of methods for quantifying rates of NAPL deple-
buildsonanumberofexistingguidancedocumentsworldwide tion or attenuation. It is assumed that the remediation endpoint
and incorporates the advances in methods for estimating the has been defined for the site based on the remedial objectives
natural attenuation rates. to address composition or saturation concerns as defined in
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ITRC (2018) (1). While the rates can be used to estimate the
1.2 The guide is focused on hydrocarbon chemicals of
timeframe to reach the remediation endpoint under natural
concern (COCs) that include petroleum hydrocarbons derived
conditions, methods for estimating the total NAPL mass and
from crude oil (for example, motor fuels, jet oils, lubricants,
timeframe are beyond the scope of this standard.
petroleum solvents, and used oils) and other hydrocarbon
NAPLs (for example, creosote and coal tars). While much of 1.7 The users of this guide should be aware of the appro-
what is discussed may be relevant to other organic chemicals, priate regulatory requirements that apply to sites where NAPL
the applicability of the standard to other NAPLs, like chlori- is present or suspected to occur. The user should consult
nated solvents or polychlorinated biphenyls (PCBs), is not applicable regulatory agency requirements to identify appro-
included in this guide. priatetechnicaldecisioncriteriaandseekregulatoryapprovals,
as necessary.
1.3 This guide is intended to evaluate the role of NAPL
natural attenuation towards reaching the remedial objectives 1.8 ASTM standard guides are not regulations; they are
and/orperformancegoalsataspecificsite;andtheselectionof consensus standard guides that may be followed voluntarily to
an appropriate remedy, including remediation through moni- support applicable regulatory requirements.This guide may be
toring of natural or enhanced attenuation, or the remedy used in conjunction with other ASTM guides developed for
transition to natural mechanisms. While the evaluation can sites with NAPL in the subsurface. The guide supplements
support some aspects of site characterization, the development characterization and remedial efforts performed under
of the conceptual site model and risk assessment, it is not international, federal, state, and local environmental programs,
intended to replace risk assessment and mitigation, such as but it does not replace regulatory agency requirements.
addressingpotentialimpacttohumanhealthorenvironment,or
1.9 SI units are primarily used in the standard, however,
need for source control.
unitsmorecommonlyusedintheindustryarealsorepresented.
1.4 Estimation of NAPL natural attenuation rates in the
1.10 The guide is organized as follows:
subsurface relies on indirect measurements of environmental
1.10.1 Section 2 lists referenced documents.
indicators and their variation in time and space. Available
1.10.2 Section 3 defines terminology used in this guide.
methods described in this standard are based on evaluation of
1.10.3 Section 4 describes the significance and use of this
biogeochemical reactions and physical transport processes
guide.
combined with data analysis to infer and quantify the natural
1.10.4 Section 5 provides the conceptual model of natural
attenuation rates for NAPL present in the vadose and/or
attenuation processes and pathways.
saturated zones.
1.10.5 Section 6 provides an overview and description of
methods for the estimation of natural attenuation rates, includ-
1
ThisguideisunderthejurisdictionofASTMCommitteeE50onEnvironmental ing:
Assessment, Risk Management and CorrectiveAction and is the direct responsibil-
ity of Subcommittee E50.04 on Corrective Action.
2
Current edition approved Oct. 1, 2022. Published December
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