1.1 本指南介绍了使用通量室来量化气体和非水相液体（NAPL）/污染物通过沸腾从沉积物到地表水的传输。沉积物中不稳定有机化合物的降解可以产生生物气体，这些气体可以通过沉积物迁移到上覆水柱中。含有疏水污染物（如NAPL）的沉积物可能粘附到气泡的表面，导致沸腾促进传输（EFT）和NAPL/污染物迁移到地表水或空气-水界面。沸腾还会导致表层沉积物的再悬浮，增强污染物向水柱的迁移。指南详细总结了影响沉积物中生物产气和沸腾速率的生物地球化学和环境因素 E3300 和扎曼普尔等人 ( 1 ) . 2 1.2 沸腾可以通过直接或间接方法定量测量。水声设备等间接测量方法测量水柱中气泡的密度以估计沸腾速率。间接方法具有收集大面积数据的优点，并提供沸腾通量空间可变性的更好分辨率。直接方法主要采用装置来捕获空气-水界面处或水柱内的气泡。 1.3 在现场研究中，使用锚定通量室的近底部测量已被证明更好地代表气体和NAPL/污染物通量 ( 2 , 3 , 4 , 5 ) 而不是基于表面的测量。虽然可以使用其他方法来测量NAPL/污染物通量的沸腾和EFT，但本指南侧重于锥形采样器式通量室的使用。本指南描述了在各种环境环境中使用的三种类型通量室的配置和使用。然而，已经成功地使用了其他通量室设计，并且本指南中提出的一般原理可以适用于其他设计(例如， 3 , 6 , 7 , 8 , 9 ). 1.4 通过随时间的监测，通量室可以有利于了解NAPL/污染物沸腾和EFT的沉积物位点速率。通量室可以部署几天或潮汐周期，以考虑时间变化。测量沉积物床附近的NAPL/污染物通量减少了水柱对数据的影响。空气-水界面的通量测量可能受到风、波浪和水柱内潜在污染源等因素的影响，而近-底部测量受这些因素的影响较小。使用通量室作为近底采样器降低了水柱或水面（或两者）中NAPL/污染物质量降解的可能性，并允许更精确地部署到具有用于计算气体或NAPL/污染物通量（或两者）的限定区域的特定位置。相反，放置在水面处的采样装置可能在部署期间四处移动，导致通量数据不太能代表限定的区域。 1.5 单位- 这些值以SI单位表示。酌情在括号中提供英制单位。当通常与标准材料相关时，附件中的单位以英制和公制单位提供。 1.6 本标准并不旨在解决与其使用相关的所有安全性问题（如果有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践并确定法规限制的适用性。 1.7 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》中确立的国际公认的标准化原则制定的。 ======意义和用途====== 4.1 沉积物中的沸腾主要是当它导致NAPL/污染物的EFT，导致对人类或生态受体的潜在风险时；明显的水质问题，例如光泽，在美国的一些州被称为叙述性水质标准；或其组合。当封盖被选为现场补救措施的一部分时，沸腾也是一个关键的设计考虑因素。量化NAPL/污染物从沉积物到地表水的气体传输和EFT对于支持关于风险、补救措施选择和补救措施设计的决策非常重要。 4.2 沸腾在自然环境中很常见；然而，当沸腾发生在与NAPL/污染物并置的区域时，沉积物基质中的疏水污染物可能粘附到气泡的表面。此外，石油烃（PHCs）可以通过PHCs的厌氧降解促进甲烷生成 ( 1 ) 气泡的向上迁移也可能导致NAPL/污染物从更深的沉积物中重新分布。从沉积物中释放的涂有NAPL/污染物的气泡可能在水面产生光泽，从而增强污染物从沉积物向地表水柱的传输。此外，气泡可能会使受污染的表层沉积物重新悬浮在水柱中（见 图1 ). 4.3 使用通量室测量NAPL/污染物的EFT是本指南涉及的主要活动。 4.4 根据沉积物现场的条件，有不同的设备选项、部署策略和数据收集技术可用。本指南提供了最合适地解决这些情况的说明和注意事项。 4.5 本指南假设CSM（指南 E3240 ）包括沉积物中NAPL/污染物的性质和程度的表征。该CSM将包括对 (1) 水文环境， (2) 沉积物和水体的物理化学特征， (3) NAPL/污染物的物理和化学特性， (4) NAPL/污染物安置机制， (5) NAPL/污染物区的物理范围，以及 (6) 人类和生态受体暴露于沉积物中的NAPL/污染物或通过NAPL/污染物释放到上覆地表水的可能性。本指南不介绍收集这些信息的手段和方法。 4.5.1 本指南假设开发的CSM确定NAPL/污染物的沸腾和EFT发生的程度和流行程度需要进一步评估。这通常通过在沉积物现场进行沸腾调查来实现（指南 E3300 ).随着更多信息的出现，CSM应该得到更新和完善。 4.6 本指南旨在用作沸腾通量室的设计、部署和数据收集的参考。本指南无意为沉积物现场调查、风险评估、监测或补救措施提供具体指导。 4.7 本指南可供沉积物场地相关各方使用，包括监管机构、项目发起人、环境顾问、场地修复专业人员、环境承包商、分析测试实验室、数据审查者和用户以及其他利益相关者。 4.8 本指南并不能取代有能力的项目规划和现场人员评估沉积物中NAPL/污染物通量的沸腾和EFT的需要。设计、建造和使用通量室所需的活动应由熟悉NAPL/污染物影响的沉积物场地表征技术、沉积物中NAPL/污染物的物理和化学特性、归宿和迁移过程、修复技术和沉积物评估协议的人员进行。本指南的用户应考虑组建一个由经验丰富的项目专业人员组成的团队，他们具有确定、计划和执行数据采集活动的专业知识。 4.9 本指南旨在适用于广泛的地方、州、部落、联邦（如综合环境响应、赔偿和责任法案）或国际司法管辖区，每个司法管辖区都有自己的监管框架。因此，本指南不提供与任何这些监管框架相关的要求或指南的详细讨论，也不旨在取代适用的法规和指南。本指南的用户需要了解工作所在司法管辖区的监管要求和指南。 4.10 本指南的用户在继续使用前应审查本指南的总体结构和组件，包括:部分 1 范围 部分 2 参考文献 部分 3 术语 部分 4 意义和用途 部分 5 通量室取样位置和时间 部分 6 通量室设计 部分 7 一般程序 部分 8 关键词 附件A1 用于较浅环境的通量室设计示例 附件A2 用于更深环境的通量室设计示例 附件A3 用于更深环境的自动化通量室设计示例 参考文献

1.1 This guide addresses the use of flux chambers for quantifying the transport of gas and non-aqueous phase liquids (NAPL)/contaminants from sediment to surface water by ebullition. Degradation of labile organic compounds in the sediment can generate biogenic gas that can migrate through the sediment into the overlying water column. Sediments that contain hydrophobic contaminants (such as NAPL) may adhere to the surface of the gas bubble resulting in ebullition-facilitated transport (EFT) and migration of NAPL/contaminants to the surface water or air–water interface. Ebullition can also result in resuspension of surficial sediment, enhancing contaminant transport to the water column. A detailed summary of biogeochemical and environmental factors that influence biogenic gas production and ebullition rate in sediments is presented in Guide E3300 and Zamanpour et al ( 1 ) . 2 1.2 Ebullition can be quantitatively measured by direct or indirect methods. Indirect measurement methods such as hydroacoustic equipment measure the density of gas bubbles in the water column to estimate ebullition rates. Indirect methods have the advantage of collecting data over large areas and provide better resolution on spatial variability of ebullition fluxes. Direct methods primarily employ a device to capture gas bubbles at the air-water interface, or within the water column. 1.3 In field studies, near-bottom measurements using anchored flux chambers have proven to better represent gas and NAPL/contaminant flux ( 2 , 3 , 4 , 5 ) than have surface-based measurements. Although other methods can be utilized to measure ebullition and EFT of NAPL/contaminant fluxes, this guide focuses on the use of cone sampler style flux chambers. This guide describes the configurations and use of three types of flux chambers used in various environmental settings. However, other flux chamber designs have been successfully used, and the general principles presented in this guide may be applicable to the other designs (for example, 3 , 6 , 7 , 8 , 9 ). 1.4 Flux chambers can be advantageous in understanding sediment site rates for both ebullition and EFT of NAPL/contaminants by monitoring over time. Flux chambers can be deployed for several days or tide cycles to account for temporal variability. Measuring NAPL/contaminant flux near the sediment bed reduces water column impacts on the data. Flux measurements at the air–water interface can be impacted by factors such as wind, waves, and potential sources of contamination within the water column, while near-bottom measurements are less affected by these factors. Use of flux chambers as near-bottom samplers reduces the potential for degradation of NAPL/contaminant mass in the water column or at the water surface (or both) and allows for more precise deployment to a specific location with a defined area for calculating gas or NAPL/contaminant flux (or both). In contrast, sampling devices placed at the water surface may move around during deployment, resulting in flux data that are less representative of a defined area. 1.5 Units— The values are presented in SI units. Imperial units are provided parenthetically, as appropriate. Units in the annexes are provided in Imperial and metric units when commonly associated with standard materials. 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. ====== Significance And Use ====== 4.1 Ebullition in sediment is a concern primarily when it causes EFT of NAPL/contaminants, resulting in potential risk to humans or ecological receptors; a perceptible water quality issue such as sheening, known as narrative water quality standards in some US states; or combinations thereof. Ebullition is also a key design consideration when capping has been selected as part of a site remedy. It is important to quantify the transport of gas and EFT of NAPL/contaminants from sediment to surface water to support decision making regarding risks, remedy selection, and remedy design. 4.2 Ebullition is common in the natural environment; however, when ebullition occurs in areas collocated with NAPL/contaminants, hydrophobic contaminants in the sediment matrix may adhere to the surface of gas bubbles. Additionally, petroleum hydrocarbons (PHCs) can contribute to methanogenesis through anaerobic degradation of PHCs ( 1 ) . The upward migration of the bubbles may also result in redistribution of NAPL/contaminants from deeper sediment. NAPL/contaminant-coated gas bubbles released from the sediment may create sheen blossoms at the water surface, thereby enhancing contaminant transport to the surface water column from the sediments. In addition, the gas bubbles may resuspend contaminated surficial sediment in the water column (see Fig. 1 ). 4.3 Using flux chambers for measuring EFT of NAPL/contaminants is the primary activity addressed by this guide. 4.4 There are varying equipment options, deployment strategies, and data collection techniques available depending on the conditions of the sediment site. This guide provides instruction and considerations for addressing these conditions most appropriately. 4.5 This guide assumes that a CSM (Guide E3240 ) has been developed that includes the characterization of the nature and extent of NAPL/contaminants in sediment. This CSM would include an understanding of (1) the hydrological setting, (2) the physical and chemical characteristics of the sediment and water body, (3) the physical and chemical characteristics of the NAPL/contaminants, (4) mechanism(s) of NAPL/contaminant emplacement, (5) the physical extent of the NAPL/contaminant zone, and (6) the potential for human and ecological receptor exposure to NAPL/contaminants in sediment, or via NAPL/contaminant release to overlying surface water. The means and methods for collecting this information are not addressed in this guide. 4.5.1 This guide assumes that the CSM developed establishes that ebullition and the EFT of NAPL/contaminants occur at a magnitude and prevalence that warrants further evaluation. This is typically accomplished by performing ebullition surveys at the sediment site (Guide E3300 ). The CSM should be updated and refined as more information becomes available. 4.6 This guide is intended to be used as a reference for the design of, deployment of, and data collection from ebullition flux chambers. This guide is not intended to provide specific guidance on sediment site investigation, risk assessment, monitoring, or remedial action. 4.7 This guide may be used by various parties involved in a sediment site, including regulatory agencies, project sponsors, environmental consultants, site remediation professionals, environmental contractors, analytical testing laboratories, data reviewers and users, and other stakeholders. 4.8 This guide does not replace the need for engaging competent project planning and field personnel to evaluate ebullition and EFT of NAPL/contaminant fluxes from sediments. Activities necessary to design, build, and use flux chambers should be conducted by persons familiar with NAPL/contaminant-impacted sediment site characterization techniques, physical and chemical properties of NAPL/contaminants 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 the expertise to scope, plan, and execute data acquisition activities. 4.9 This guide is intended to be applicable at a broad range of local, state, tribal, federal (such as the Comprehensive Environmental Response, Compensation and Liability Act), or international jurisdictions, each with its own regulatory framework. As such, this guide does not provide a detailed discussion of the requirements or guidance associated with any of these regulatory frameworks, nor is it intended to supplant applicable regulations and guidance. The user of this guide will need to be aware of the regulatory requirements and guidance in the jurisdiction where the work is being performed. 4.10 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 Flux Chamber Sampling Locations and Timing Section 6 Flux Chamber Design Section 7 General Procedures Section 8 Keywords Annex A1 Example Flux Chamber Design for Shallower Environments Annex A2 Example Flux Chamber Design for Deeper Environments Annex A3 Example Automated Flux Chamber Design for Deeper Environments References