In 2023, ITRC published the Sediment Cap Chemical Isolation Guidance to supplement the 2014 Contaminated Sediments Remediation Guidance with the goal of improving consistency in sediment cap performance outcomes. Sediment capping is a commonly selected remediation approach and numerous designs have been completed. Previous cap designs have been evaluated in multiple ways, and these varying approaches have led to some differences in selection of chemical design criteria, construction tolerance specifications, and monitoring/maintenance objectives for sites with similar characteristics and contaminants, leading to different expectations for long-term performance and reliability. The ITRC Sediment Cap Chemical Isolation Guidance provides a framework for the design, construction, and long-term monitoring of the chemical isolation function of sediment caps. The framework consists of an iterative design process informed by site-specific data that balances achievement of chemical design criteria, physical design constraints, constructability and permitting requirements. In addition, the guidance summarizes key construction considerations and presents a recommended approach for monitoring and evaluating long-term chemical isolation performance. The recommended framework presented in the Sediment Cap Chemical Isolation Guidance is illustrated below. The Sediment Cap Chemical Isolation Training will cover several key elements of the recommended framework, including: A capping overview that summarizes objectives of capping, role of the chemical isolation layer, and generic cap types and compositions. A discussion of performance objectives and design concepts that includes the selection of chemical isolation performance targets criteria and development of design criteria while considering the site setting and conceptual site model elements. An overview of chemical isolation layer modeling tools and discussion of their applicability to support chemical isolation design, important model input parameters, and the impact of uncertainty and sensitivity of modeling results. A summary of chemical isolation construction considerations, including an overview of available construction methods and tolerances and quality assurance and quality control measures. A discussion of cap performance monitoring and maintenance objectives and approaches that include developing monitoring objectives to assess chemical isolation performance and methods for guiding long-term maintenance decisions. We encourage participants to review the ITRC Sediment Cap Chemical Isolation Guidance (SD-1) before and after the training to become familiar with the topics and recommendations discussed during the training. This training is intended for all environmental professionals working in the field of sediment capping projects, including regulators and other government agency staff, consultants, project stakeholders, and industry. To view this archive online or download the slides associated with this seminar, please visit http://www.clu-in.org/conf/itrc/sd-1_021726/

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