Remedial Investigation/feasibility Study Research Articles

Conceptual Site Model for Newark Bay—Hydrodynamics and Sediment Transport

A conceptual site model (CSM) has been developed for the Newark Bay Study Area (NBSA) as part of the Remedial Investigation/Feasibility Study (RI/FS) for this New Jersey site. The CSM is an evolving document that describes the influence of physical, chemical and biological processes on contaminant fate and transport. The CSM is initiated at the start of a project, updated during site activities, and used to inform sampling and remediation planning. This paper describes the hydrodynamic and sediment transport components of the CSM for the NBSA. Hydrodynamic processes are influenced by freshwater inflows, astronomical forcing through two tidal straits, meteorological conditions, and anthropogenic activities such as navigational dredging. Sediment dynamics are driven by hydrodynamics, waves, sediment loading from freshwater sources and the tidal straits, sediment size gradation, sediment bed properties, and particle-to-particle interactions. Cohesive sediment transport is governed by advection, dispersion, aggregation, settling, consolidation, and erosion. Noncohesive sediment transport is governed by advection, dispersion, settling, armoring, and transport in suspension and along the bed. The CSM will inform the development and application of a numerical model that accounts for all key variables to adequately describe the NBSA’s historical, current, and future physical conditions.

Collecting, Analyzing, and Visualizing Environmental Data Using Innovative GIS Techniques at CampSibert

Former Camp Sibert was a large-scale chemical warfare materials (CWM) training site in the United States from late 1942 through early 1945. In addition to chemical training, several types and calibers of conventional weapons were also fired there. At the end of World War II, this formerly used defense site (FUDS) was closed. CWM, unexploded ordnance (UXO), and munitions and explosives of concern (MEC) are safety hazards that may constitute an imminent and substantial danger to the public and the environment. Since 1997, Parsons, awarded by the U.S. Army Corps of Engineers, has conducted numerous phased engineering evaluation/cost analysis (EE/CA), remedial investigation/feasibility study (RI/FS), and removal action (RA) on the CWM and conventional MEC sites inside former Camp Sibert. This paper discusses how we utilized innovative GIS techniques during these environmental investigations to collect, store, process, analyze, and visualize the large amount of the projects data. They have been proven to be useful, efficient, reliable, and cost-effective.

Baseline Ecological Risk Assessment of the Calcasieu Estuary, Louisiana: Part 1. Overview and Problem Formulation

A remedial investigation/feasibility study (RI/FS) of the Calcasieu Estuary cooperative site was initiated in 1998. This site, which is located in the southwestern portion of Louisiana in the vicinity of Lake Charles, includes the portion of the estuary from the saltwater barrier on the Calcasieu River to Moss Lake. As part of the RI/FS, a baseline ecological risk assessment (BERA) was conducted to assess the risks to aquatic organisms and aquatic-dependent wildlife exposed to environmental contaminants. The purpose of the BERA was to determine if adverse effects on ecological receptors are occurring in the estuary; to evaluate the nature, severity, and areal extent of any such effects; and to identify the substances that are causing or substantially contributing to effects on ecological receptors. This article describes the environmental setting and site history, identifies the chemicals of potential concern, presents the exposure scenarios and conceptual model for the site, and summarizes the assessment and measurement endpoints that were used in the investigation. Two additional articles in this series describe the results of an evaluation of effects-based sediment-quality guidelines as well as an assessment of risks to benthic invertebrates associated with exposure to contaminated sediment.

The Bunker Hill Hillsides: Site History and Planning for Early Successional Restoration on the Nation's Largest Superfund Site

Good project planning is essential to developing appropriate and achievable restoration programs. This paper discusses the history of the Bunker Hill site and its prior condition. It further discusses the planning approaches that were used and the guidance statements that were obtained. These guidance statements generated clarity for prescription development and measurement of success on the Bunker Hill hillsides project in the Silver Valley of northern Idaho. The hillsides are part of the Bunker Hill Superfund site, a 54 km 2 area centered in Kellogg, Idaho that has been contaminated by heavy metals from a long history of mining and metallurgical activity. Environmental documentation found within the site's remedial investigation/feasibility study (RI/FS) and Record of Decision provided some general concepts of restoration work that could occur on the site but was insufficient to avoid long-term conflicts between stakeholders. In particular, a 425 ha area on the south end of the site was composed of steep, heavily eroded, denuded, and inaccessible hillsides that were contributing substantial quantities of sediment to the Coeur d'Alene River basin. Successful restoration of the hillsides required agreements between stakeholders with respect to specific goals, objectives, performance standards, and monitoring methods. These and other guidance elements guide design and execution of the restoration program. Accordingly, the authors convened a series of three workshops with project stakeholders that outlined project-specific guidance statements for this undertaking to ensure that conflicts were minimized and that the path forward for the project was well-founded. These statements have guided project development, execution, monitoring, and mid-course corrections and has resulted in a successful project with few to no stakeholder conflicts. Additional keywords: conflict resolution, goals, objectives, performance standards, monitoring methods.

Determination of a site-specific reference dose for methylmercury for fish-eating populations.

Determination of a site-specific reference dose for methylmercury for fish-eating populations.

Risk‐based screening: Streamlining the baseline risk assessment process at federal facilities

AbstractRecent EPA guidance has focused on using risk assessment to support remedial action decisions (U.S. 1991). However, experience has shown that the Baseline Risk Assessment (BRA) is very time‐consuming and often yields insufficient guidance to remedial design engineers in evaluation and selection of remedial alternatives. This article presents an approach for streamlining the BRA for a Remedial Investigation/Feasibility Study (RI/FS) under CERCLA and for a Remedial Facility Investigation/Corrective Measures Study (RFI/CMS) under RCRA. It uses a combination of background concentrations, applicable or relevant and appropriate requirements (ARARs), and risk‐based preliminary remediation goals (PRGs) to set conservative, media‐specific screening levels for all constituents of concern (COCs) at a facility. These screening levels streamline the RI/FS and RFI/CMS process by reducing the number of areas of concern (AOCs) and COCs that require detailed risk assessment and providing remedial design engineers with early guidance on areas and constituents possibly requiring remediation, thus allowing preliminary technology identification and evaluation to proceed concurrently with the BRA.This article illustrates the utility of this approach, describing its application at a federal facility in the desert Southwest. The case study site was an ideal candidate for the screening approach in that it covered more than 22,000 acres, much of which was expected to be uncontaminated. Of the 45 AOCs initially identified in the Field Investigation Work Plan, only four AOCs required detailed risk evaluation after screening. In addition, the article describes the approach used in the case study site to screen potential risks posed by exposures to the interiors of concrete weapons storage bunkers (igloos).

Characterizing soils for hazardous waste site assessments

This paper provides a review and justification of the minimum data needed to characterize soils for hazardous waste site assessments and to comply with the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). Scientists and managers within the regulatory agency and the liable party need to know what are the important soil characteristics needed to make decisions about risk assessment, what areas need remediation and what remediation options are available. If all parties involved in characterizing a hazardous waste site can agree on the required soils data set prior to starting a site investigation, data can be collected in a more efficient and less costly manner. Having the proper data will aid in reaching decisions on how to address concerns at, and close-out, hazardous waste sites.This paper was prepared to address two specific concerns related to soil characterization for CERCLA remedial response. The first concern is the applicability of traditional soil classification methods to CERCLA soil characterization. The second is the identification of soil characterization data type required for CERCLA risk assessment and analysis of remedial alternatives. These concerns are related, in that the Data Quality Objective (DQO) process addresses both. The DQO process was developed in part to assist CERCLA decision-makers in identifying the data types, data quality, and data quantity required to support decisions that must be made during the remedial investigation/feasibility study (RI/FS) process. Data Quality Objectives for Remedial Response Activities: Development Process (US EPA, 1987a) is a guidebook on developing DQOs. This process as it relates to CERCLA soil characterization is discussed in the Data Quality Objective Section of this paper.

A Management Systems Review of the Superfund RI/FS: Opportunities for Streamlining

The Management Systems Review is an important component of EPA’s quality assurance program. MSRs enable managers to assess the effectiveness of environmental data operations and the quality assurance/ quality control activities designed to ensure that the results are of the expected quality. These reviews inform managers about aspects of the environmental data operation that are working well and those which may warrant some improvement. A recent review of the Superfund remedial investigation/feasibility study (RI/FS) has shown that the MSR is an excellent tool for providing a systematic definition of complex environmental data operations and for enabling a thorough analysis of these operations. The MSR utilized information gathered from interviews of Regional staff and management and from case studies of recently completed RI/FSs. The findings indicated that environmental data play an important role in most RI/FS decisions and that thorough and structured scoping is critical to the effectiveness of the RI...