ASTM E3242-23

SIGNIFICANCE AND USE 4.1 Intended Use: 4.1.1 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: 4.2.1 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: 4.3.1 This guide should be used in conjunction with other ASTM guides listed in 2.1 (especially Guides E3344 and E3382); this guide should also be used in conjunction with the material in the References at the end of this guide (including 1). Utilizing these reference materials will direct the user in developing representative background concentrations for a sediment site. 4.4 Flexible Site-Specific Implementation: 4.4.1 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: 4.5.1 This guide is intended to be applicable to a broad range of local, state, tribal, federal, 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... SCOPE 1.1 This guide describes data visualization, statistical, forensic chemistry and geochemical methodologies (including case studies) used in the evaluation of candidate background data sets; this evaluation leads to the development of representative background data sets for the sediment site. Statistical methodologies can then be applied to the representative background data sets to develop background threshold values (BTVs) that are measures of the upper limit of representative sediment background concentrations for the sediment site. In addition, representative background data sets and sediment site data sets can be compared using two-sample statistical tests to determine if there are statistically significant differences (at a specified confidence level) between the two data sets (such as, the median or mean values of the two data sets are significantly different). 1.1.1 This guide is intended to inform, complement, and support, but not supersede the guidelines established by local, state, tribal, federal, or international agencies. 1.2 Technically defensible representative sediment background concentrations are critical for several purposes (1).2 These include sediment site delineation, establishing remedial goals and cleanup levels, remedy selection, assessment of risks posed by representative background concentrations, and establishing appropriate post-remedial monitoring plans. 1.3 The overarching framework for the development of representative sediment background concentrations at sediment sites is presented in Guide E3382. Guide E3240 provides a general discussion of how conceptual site model (CSM) development fits into the risk-based corrective action framework for contaminated sediment sites, while Guide E3382 provides a detailed discussion of the elements of a sediment site CSM that need to be considered when developing representative sediment background concentrations. Guide E3344 describes how to se...