Significance and Use
4.1 Intended Use—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.
4.2 Importance of the CSM—The CSM should be continuously updated and refined to describe the physical properties, chemical composition and occurrence, biologic features, and environmental conditions of the sediment corrective action project (Guide E1689).
4.3 Reference Material—This guide should be used in conjunction with other ASTM guides listed in 2.1 (especially Guide E3242); this guide should also be used in conjunction with the material in the References at the end of this guide (including 3). Utilizing these reference materials will direct the user in deriving representative sediment background concentrations.
4.4 Flexible Site-Specific Implementation—This guide provides a systematic but flexible framework to accommodate variations in approaches by regulatory agencies and by the user based on project objectives, site complexity, unique site features, regulatory requirements, newly developed guidance, newly published scientific research, changes in regulatory criteria, advances in scientific knowledge and technical capability, and unforeseen circumstances.
4.5 Regulatory Frameworks—This guide is intended to be applicable at a broad range of local, state, tribal, federal (such as CERCLA), or international jurisdictions, each with its own unique 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.
4.6 Systematic Project Planning and Scoping Process—When applying this guide, the user should undertake a systematic project planning and scoping process to collect information to assist in making site-specific, user-defined decisions for a particular project, including assembling an experienced team of project professionals (that is, experienced practitioners familiar with current sediment site characterization and remediation techniques, as well as geochemistry and statistics). These practitioners should have the appropriate expertise to scope, plan, and execute a sediment data acquisition and analysis program. This team may include, but is not limited to, project sponsors, environmental consultants, toxicologists, site remediation professionals, analytical chemists, geochemists, and statisticians.
4.6.1 Depending on the regulatory requirements in a jurisdiction, the choice of background reference areas may need to consider critical habitats and ecological receptors.
4.6.2 In this guide, sediment (3.1.8) is defined as material being found at the bottom of a water body. Upland soils of sedimentary origin are excluded from consideration as sediment in this guide.
4.7 Other Considerations—This guide does not cover all components of a program to derive representative sediment background concentrations.
4.7.1 Sediment sampling and laboratory analyses are not covered in this guide. Guide E3163 contains extensive information concerning sediment sampling and laboratory analyses.
4.7.2 Data quality objectives are not covered in this guide. Data quality objectives are described in (4).
4.7.3 Background study design considerations are not covered in this guide but are described in other references, including Guides E3163 and E3164, as well as (5).
4.7.4 Data extraction methodologies to obtain representative background concentrations from sediment site data sets are not covered here, but are explained in Guide E3242. Identification and removal of outliers from data sets are discussed in detail in Guide E178, as well as Guide E3242. Other statistical and geochemical methods used in deriving representative background concentrations are also discussed in Guide E3242.
4.7.5 Geospatial analysis considerations are not thoroughly discussed in this guidance but are discussed in more depth relative to environmental evaluations in (6), which focuses on quality assurance concerns relative to geospatial analyses.
4.7.6 In this guide, only the concentrations of PCOCs are considered to be in scope. Residual background radioactivity is considered to be out of scope for this guide.
4.8 Structure and Components of this Guide—The user of this guide should review the overall structure and components of this guide before proceeding with use, including:
Significance and Use
Overview of Representative Background Concentrations and Calculation Process
Background Reference Area Selection Criteria
1.1 This guide focuses on the selection of sediment background reference areas from aquatic environments for the purpose of determining representative sediment background concentrations. These concentrations are typically used in contaminated sediment corrective actions performed under various regulatory programs, including the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). Although many of the references cited in this guide are CERCLA oriented, the guide is applicable to remedial actions performed under local, state, tribal, federal, and international cleanup programs. However, this guide does not describe the requirements for each jurisdiction.
1.1.1 The sediment background reference areas chosen using this guide will need to be approved by the regulatory agency having jurisdiction (or they should take no exception to the areas chosen), especially if the representative background sediment concentrations will potentially be used to develop sediment remedial criteria.
1.2 This guide provides a framework to select appropriate sediment background reference areas for collection of sediment data in the determination of representative sediment background concentrations. It is intended to inform, complement, and support, but not supersede, local, state, tribal, federal, or international guidelines.
1.2.1 This guide is designed to apply to contaminated sediment sites where sediment data have been collected and are readily available. Additionally, it assumes that risk assessments have been performed, so that the potential contaminants of concern (PCOCs) that exceed risk-based thresholds have been identified. This guide can be applied at multiple points within the project life cycle (such as site assessment and remedial design).
1.2.2 Furthermore, this guide presumes that the identified risk-based thresholds are low enough to pose corrective action implementation challenges or that the sediment site is subject to recontamination from ongoing anthropogenic or natural sources that are not controlled. In either case, representative sediment background concentrations are useful for determining the extent of corrective remedial actions (when used as remedial goals), evaluating risks posed by representative background concentrations, and establishing appropriate post-remedial monitoring plans.
1.2.3 A case study for selecting a background reference area using a tiered decision analysis approach is presented in Appendix X1. It compares various characteristics of a hypothetical sediment site associated with a former manufactured gas plant (MGP) facility to three candidate background reference areas and identifies the reference area that best satisfies the decision analysis objectives.
1.3 Methodologies used to determine representative background concentrations at contaminated sediment sites are not discussed in this guide—refer to Guide E3242 for a discussion of these methodologies.
1.4 Related ASTM Standards—This guide is related to Guide E3242, which provides a framework for determination of representative sediment background concentrations, including statistical and geochemical considerations. This guide is also related to Guide E3164, which addresses corrective action monitoring before, during, and after sediment remediation activities, as well as Guide E3163, which concerns sediment sampling and analytical techniques used during sediment corrective action projects. Guide D4823, which concerns sediment core sampling, is also related to this guide.
1.4.1 Specifically, this guide is intended to be used in conjunction with the framework to calculate representative background values outlined in Guide E3242, to help ensure appropriate background reference areas are chosen for use in representative background concentration calculations.
1.5 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this guide.
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.