1.1 本指南适用于以残留相、游离相或流动相形式存在LNAPL的现场，以及LNAPL是土壤、地下水和土壤蒸汽影响源的任何地方。使用本指南可能会显示LNAPL存在于之前未识别的地方。关于LNAPL相位和评估其潜在存在的方法的信息包含在 4.3 ，指南术语在第节中 3. ，技术词汇在 附录X7和 附录X8 . 无花果 1是总结本指南程序的流程图。 1.2 本指南旨在补充RBCA过程中开发的概念站点模型（指南 E1739 和 E2081年 )和概念场地模型标准（指南 E1689 )充分详细地考虑LNAPL条件，以评估风险和补救措施选项。 1.3 应遵循联邦、州和地方监管政策和法规，并构成确定补救目标的基础，无论是基于风险还是其他。无花果 1说明了本指南与其他相关指南和参考文献之间的相互作用。 1.4 本指南主要关注石油和其他化学品液化石油气。某些技术方面适用于密集NAPL（DNAPL），但本指南并未解决DNAPL的额外复杂性。 1.5 LNAPL的复合化学和物理性质是组成LNAPL的单个化学品的函数。LNAPL的性质及其可能存在的地下条件因现场而异。LCSM所需的复杂性和详细程度取决于暴露途径和风险以及所需补救措施的范围和程度。 LCSM遵循足够详细的分层开发，以进行风险评估和补救措施决策。当现有信息无法回答有关LNAPL的基本问题时，通常需要额外的数据收集或技术分析。 1.6 本指南不制定新的风险评估协议。它旨在与现有的基于风险的纠正行动指南（例如，指南）结合使用 E1739 和 E2081年 )和监管机构要求（例如，美国环保局1989、1991、1992、1996、1997）。 1.7 本指南帮助用户开发LCSM，在此基础上应用决策框架来帮助用户选择补救措施选项。 1.8 本指南的目标是使用适当规模的现场设备为LNAPL纠正措施提供可靠的技术支持- 掌握控制LNAPL的物理和化学过程以及地下水和土壤蒸汽中的相关羽状物的具体知识。 1.9 本指南提供了灵活性，并帮助用户根据LCSM制定一般LNAPL站点目标。本指南确认LNAPL现场目标由监管、业务、区域、社会和其他现场特定因素决定。在指南的背景下 E2081年 RBCA过程中，这些因素被称为技术政策决策。 1.10 补救指标是根据现场目标定义的，是补救行动的可测量属性。修复指标可能包括环境效益，如通量控制、风险降低或化学寿命缩短。补救指标还可能包括成本，如安装成本、能源使用、业务损害、废物产生、水处理等。 补救指标用于补救方案的决策分析和跟踪已实施补救措施替代方案的性能。 1.11 本指南不提供选择一种补救技术而非另一种补救技术的程序。相反，它建议技术选择决策基于LCSM、良好的专业判断和LNAPL站点目标。这些方面是复杂和跨学科的。需要适当的用户知识、技能和判断。 1.12 本指南不是补救措施系统工程分析和设计的详细程序。它旨在由合格的专业人员根据LCSM中包含的科学和技术信息制定补救策略。补救策略应与现场目标一致。 辅助工程分析和设计应根据相关专业工程标准、规范和要求进行。 1.13 ASTM标准不是联邦或州法规；它们是自愿的共识标准。 1.14 使用本指南时应遵循以下原则: 1.14.1 收集的数据和信息应与开发技术健全的LCSM相关，并具有足够的数量和质量。 1.14.2 无论现在还是将来，所采取的补救行动都应保护人类健康和环境。 1.14.3 补救措施应具有满足LNAPL现场目标的合理概率。 1.14.4 实施的补救措施不应导致比采取措施前更大的现场风险。 1.14.5 应遵守适用的联邦、州和地方法规（例如，废物管理要求、地下水指定、工人保护）。 1.15 本指南组织如下: 1.15.1 部分 2. 列出相关的ASTM文件。 1.15.2 部分 3. 定义本指南中使用的术语。 1.15.3 部分 4. 包括本指南的摘要。 1.15.4 部分 5. 提供本指南的意义和用途。 1.15.5 部分 6. 介绍LCSM的组件。 1.15.6 部分 7. 提供分步程序。 1.15.7 以下附加信息提供了非强制性附录: 1.15.7.1 附录X1 提供额外的LNAPL读数。 1.15.7.2 附录X2 概述了多相建模。 1.15.7.3 附录X3 提供了与LCSM有关的筛选级别计算示例。 1.15.7.4 附录X4 提供有关数据收集技术的信息。 1.15.7.5 附录X5 提供了示例修正指标。 1.15.7.6 附录X6 提供了两个使用LNAPL指南的简化示例。 1.15.7.7 附录X7和 附录X8 是与LNAPL决策相关的技术术语词汇表。 1.15.8 参考列表包含在文件末尾。 1.16 附录仅供参考，不作为本指南的强制性章节。 1.17 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.18 本指南提供了有组织的信息收集或一系列选项，并不推荐具体的行动方案。 本文件不能取代教育或经验，应与专业判断一起使用。并非本指南的所有方面都适用于所有情况。本ASTM标准不代表或取代必须根据其判断给定专业服务的充分性的谨慎标准，也不应在不考虑项目的许多独特方面的情况下应用本文件。本文件标题中的“标准”一词仅表示该文件已通过ASTM共识程序获得批准。 1.19 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 本指南将帮助用户回答有关地下LNAPL发生和行为的简单和基本问题。它将帮助用户识别特定的基于风险的驱动因素和非风险因素，以便在现场采取行动，并根据这些驱动因素和因素对资源进行优先排序。 5.2 本指南中描述的现场管理决策过程包括几个功能，这些功能只是解决特定活动目标的标准化方法的示例。例如 表1 提供了LNAPL存在的示例指标。 表1 用户应使用经过修改的LNAPL指标列表进行定制，该列表在技术上适用于正在处理的站点或站点组。 5.3 本指南提倡对第1层LCSM使用简单分析和可用数据，以利用现有数据，并潜在地以新的方式解释现有数据。 一级LCSM旨在确定哪些地方可能需要额外数据，以及哪些地方可以使用现有数据和边界估计做出决策。 5.4 本指南将Tier 2和Tier 3中的LCSM扩展为详细的动态描述，其中考虑了与LNAPL相关的三维羽流几何形状、化学和通量，这些都是化学和位置特定的。 5.5 本指南促进了现有现场数据的有效使用，同时认识到信息可能仅与LNAPL身体状况间接相关。本指南还提供了一个框架，用于收集额外数据并定义改进LCSM对补救决策的价值。 5.6 通过定义LCSM的关键组件，本指南有助于确定了解现场LNAPL发生和行为的框架。 本指南建议用户和利益相关者确定具体的LNAPL现场目标，补救指标应基于LNAPL现场目标。LNAPL现场目标应基于各种问题，包括: 5.6.1 潜在的人类健康风险以及对相关生态受体和栖息地的风险； 5.6.2 具体监管要求；和 5.6.3 美学或其他管理目标。 5.7 本指南提供了一个框架，用户可以通过该框架指定在LCSM条件下一致且可实现的效益补救指标。 5.8 指导的重点是做出正确决策所需的信息，而不是可能用于获取该信息的具体方法或评估。本指南侧重于现场数据，而非建模，尽管建模显然被认为是生成场景和LNAPL主体条件包围条件的有用工具。 中提供了用于开发LCSM的现场特定数据的有限示例 附录X6 . 5.9 通过定义作用于LCSM的补救措施的特定、可测量属性，用户可以使用一组一致的因素和期望的评估来确定哪些措施可能可行，哪些可能不可行。 5.10 健全的LCSM将导致更好地决定补救措施。以LCSM为前提的现场管理决策过程旨在提高LNAPL风险评估和补救措施的决策效率和一致性。 5.11 多相LNAPL问题的复杂性以及可用的各种分析和解释方法导致了LNAPL现场决策的不确定性，有时导致对补救结果的误导性预期。 5.12 当前的风险评估方法通常假设LNAPL是一个无限的化学品来源。通过明确描述LNAPL主体的化学成分和物理特征，将LNAPL视为相关化学品的源材料，可以更好地定义修复决策。 5.13 当LNAPL是风险的主要来源时，LNAPL应该是补救措施的主要目标，这些补救措施应该通过遵循本指南中描述的决策评估来确定。 5.14 LNAPL监管政策通过油井中的小LNAPL厚度来定义修复指标，在现场特定的基础上，通常与基于风险的筛选水平（RBSL）以及关于LNAPL流动性和可回收性的当前技术知识不一致。 LNAPL补救指标应与当前或潜在的未来暴露和风险以及特定现场的其他非风险驱动因素相联系。 5.15 鼓励本指南用户确定公众参与和利益相关者参与LCSM开发和现场管理决策过程的适当流程。 5.16 通过提供一个灵活的框架，本指南将继续在原则上适用，同时通过未来的研究工作研究LNAPL运动中的许多未知和不确定性以及所有羽流阶段（例如，吸附、溶解、蒸汽）中的相关风险。与LCSM本身一样，这是一份“活的”文件，必须包含知识和技术的进步。

1.1 This guide applies to sites with LNAPL present as residual, free, or mobile phases, and anywhere that LNAPL is a source for impacts in soil, ground water, and soil vapor. Use of this guide may show LNAPL to be present where it was previously unrecognized. Information about LNAPL phases and methods for evaluating its potential presence are included in 4.3 , guide terminology is in Section 3 , and technical glossaries are in Appendix X7 and Appendix X8 . Fig. 1 is a flowchart that summarizes the procedures of this guide. 1.2 This guide is intended to supplement the conceptual site model developed in the RBCA process (Guides E1739 and E2081 ) and in the conceptual site model standard (Guide E1689 ) by considering LNAPL conditions in sufficient detail to evaluate risks and remedial action options. 1.3 Federal, state, and local regulatory policies and statutes should be followed and form the basis of determining the remedial objectives, whether risk-based or otherwise. Fig. 1 illustrates the interaction between this guide and other related guidance and references. 1.4 Petroleum and other chemical LNAPLs are the primary focus of this guide. Certain technical aspects apply to dense NAPL (DNAPL), but this guide does not address the additional complexities of DNAPLs. 1.5 The composite chemical and physical properties of an LNAPL are a function of the individual chemicals that make-up an LNAPL. The properties of the LNAPL and the subsurface conditions in which it may be present vary widely from site to site. The complexity and level of detail needed in the LCSM varies depending on the exposure pathways and risks and the scope and extent of the remedial actions that are needed. The LCSM follows a tiered development of sufficient detail for risk assessment and remedial action decisions to be made. Additional data collection or technical analysis is typically needed when fundamental questions about the LNAPL cannot be answered with existing information. 1.6 This guide does not develop new risk assessment protocols. It is intended to be used in conjunction with existing risk-based corrective action guidance (for example, Guides E1739 and E2081 ) and regulatory agency requirements (for example, USEPA 1989, 1991, 1992, 1996, 1997). 1.7 This guide assists the user in developing an LCSM upon which a decision framework is applied to assist the user in selecting remedial action options. 1.8 The goal of this guide is to provide sound technical underpinning to LNAPL corrective action using appropriately scaled, site-specific knowledge of the physical and chemical processes controlling LNAPL and the associated plumes in ground water and soil vapor. 1.9 This guide provides flexibility and assists the user in developing general LNAPL site objectives based on the LCSM. This guide recognizes LNAPL site objectives are determined by regulatory, business, regional, social, and other site-specific factors. Within the context of the Guide E2081 RBCA process, these factors are called the technical policy decisions. 1.10 Remediation metrics are defined based on the site objectives and are measurable attributes of a remedial action. Remediation metrics may include environmental benefits, such as flux control, risk reduction, or chemical longevity reduction. Remediation metrics may also include costs, such as installation costs, energy use, business impairments, waste generation, water disposal, and others. Remediation metrics are used in the decision analysis for remedial options and in tracking the performance of implemented remedial action alternatives. 1.11 This guide does not provide procedures for selecting one type of remedial technology over another. Rather, it recommends that technology selection decisions be based on the LCSM, sound professional judgment, and the LNAPL site objectives. These facets are complex and interdisciplinary. Appropriate user knowledge, skills, and judgment are required. 1.12 This guide is not a detailed procedure for engineering analysis and design of remedial action systems. It is intended to be used by qualified professionals to develop a remediation strategy that is based on the scientific and technical information contained in the LCSM. The remediation strategy should be consistent with the site objectives. Supporting engineering analysis and design should be conducted in accordance with relevant professional engineering standards, codes, and requirements. 1.13 ASTM standards are not federal or state regulations; they are voluntary consensus standards. 1.14 The following principles should be followed when using this guide: 1.14.1 Data and information collected should be relevant to and of sufficient quantity and quality to develop a technically-sound LCSM. 1.14.2 Remedial actions taken should be protective of human health and the environment now and in the future. 1.14.3 Remedial actions should have a reasonable probability of meeting the LNAPL site objectives. 1.14.4 Remedial actions implemented should not result in greater site risk than existed before taking actions. 1.14.5 Applicable federal, state, and local regulations should be followed (for example, waste management requirements, ground water designations, worker protection). 1.15 This guide is organized as follows: 1.15.1 Section 2 lists associated and pertinent ASTM documents. 1.15.2 Section 3 defines terminology used in this guide. 1.15.3 Section 4 includes a summary of this guide. 1.15.4 Section 5 provides the significance and use of this guide. 1.15.5 Section 6 presents the components of the LCSM. 1.15.6 Section 7 offers step-by-step procedures. 1.15.7 Nonmandatory appendices are supplied for the following additional information: 1.15.7.1 Appendix X1 provides additional LNAPL reading. 1.15.7.2 Appendix X2 provides an overview of multiphase modeling. 1.15.7.3 Appendix X3 provides example screening level calculations pertaining to the LCSM. 1.15.7.4 Appendix X4 provides information about data collection techniques. 1.15.7.5 Appendix X5 provides example remediation metrics. 1.15.7.6 Appendix X6 provides two simplified examples of the use of the LNAPL guide. 1.15.7.7 Appendix X7 and Appendix X8 are glossaries of technical terminology relevant for LNAPL decision-making. 1.15.8 A reference list is included at the end of the document. 1.16 The appendices are provided for additional information and are not included as mandatory sections of this guide. 1.17 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. 1.18 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project's many unique aspects. The word “Standard” in the title of this document means only that the document has been approved through the ASTM consensus process. 1.19 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 ====== 5.1 This guide will help users answer simple and fundamental questions about the LNAPL occurrence and behavior in the subsurface. It will help users to identify specific risk-based drivers and non-risk factors for action at a site and prioritize resources consistent with these drivers and factors. 5.2 The site management decision process described in this guide includes several features that are only examples of standardized approaches to addressing the objectives of the particular activity. For example, Table 1 provides example indicators of the presence of LNAPL. Table 1 should be customized by the user with a modified list of LNAPL indicators as technically appropriate for the site or group of sites being addressed. 5.3 This guide advocates use of simple analyses and available data for the LCSM in Tier 1 to make use of existing data and to interpret existing data potentially in new ways. The Tier 1 LCSM is designed to identify where additional data may be needed and where decisions can be made using existing data and bounding estimates. 5.4 This guide expands the LCSM in Tier 2 and Tier 3 to a detailed, dynamic description that considers three-dimensional plume geometry, chemistry, and fluxes associated with the LNAPL that are both chemical- and location-specific. 5.5 This guide fosters effective use of existing site data, while recognizing that information may be only indirectly related to the LNAPL body conditions. This guide also provides a framework for collecting additional data and defining the value of improving the LCSM for remedial decisions. 5.6 By defining the key components of the LCSM, this guide helps identify the framework for understanding LNAPL occurrence and behavior at a site. This guide recommends that specific LNAPL site objectives be identified by the user and stakeholders and remediation metrics be based on the LNAPL site objectives. The LNAPL site objectives should be based on a variety of issues, including: 5.6.1 Potential human health risks and risks to relevant ecological receptors and habitats; 5.6.2 Specific regulatory requirements; and 5.6.3 Aesthetic or other management objectives. 5.7 This guide provides a framework by which users specify benefit remediation metrics that are consistent and achievable given the conditions of the LCSM. 5.8 Guidance is focused on the information needed to make sound decisions rather than specific methods or evaluations that might be used in deriving that information. This guide is weighted toward field data rather than modeling, though modeling is clearly recognized as a useful tool in generating scenarios and bracketing conditions of the LNAPL body conditions. Limited examples of site specific data used to develop the LCSM are provided in Appendix X6 . 5.9 By defining specific, measurable attributes of remedial actions acting upon an LCSM, users can determine which actions may be feasible and which likely are not, using an evaluation of a consistent set of factors and expectations. 5.10 A sound LCSM will lead to better decisions about remedial actions. The site management decision process premised on the LCSM is intended to result in more efficient and consistent decision-making about LNAPL risk evaluations and remedial actions. 5.11 The complexity of multiphase LNAPL issues and the wide variety of analysis and interpretation methods that are available has lead to uncertainty in decision-making regarding sites with LNAPL and has sometimes resulted in misleading expectations about remedial outcomes. 5.12 Current risk assessment methods often assume the LNAPL is an infinite source of chemicals of concern. The remediation decision-making may be better defined by considering the LNAPL as the source material for chemicals of concern by explicitly characterizing the chemical composition and physical characteristics of the LNAPL body. 5.13 When LNAPL presents the main source of risk, the LNAPL should be the primary target of remedial actions and those remedial actions should be determined by following the decision evaluations described in this guide. 5.14 LNAPL regulatory policies that define remediation metrics by small LNAPL thicknesses in wells are, on a site-specific basis, often inconsistent with risk-based screening levels (RBSLs) and with current technical knowledge regarding LNAPL mobility and recoverability. LNAPL remediation metrics should be connected to the current or potential future exposures and risks, as well as to other non-risk drivers present for a particular site. 5.15 The user of this guide is encouraged to identify the appropriate process for public involvement and stakeholder participation in the development of the LCSM and the site management decision process. 5.16 By providing a flexible framework, this guidance will continue to be applicable in principle while the many unknowns and uncertainties in LNAPL movement and the associated risks in all plume phases (for example, sorbed, dissolved, vapor) are studied through future research efforts. Like the LCSM itself, this is a “living” document that must embrace advances in knowledge and in technology.