Edward C. Thornton

Data Quality Objectives Summary Report - Designing a Groundwater Monitoring Network for the 200-BP-5 and 200-PO-1 Operable Units

This document presents the results of a series of interviews held with technical, management, and regulatory staff to determine the groundwater data quality objectives (DQOs) for monitoring activities associated with the 200-BP-5 and 200-PO-1 operable units located in the Hanford Site 200 East Area. This assessment is needed to address changing contaminant plume conditions (e.g., plume migration) and to ensure that monitoring activities meet the requirements for performance monitoring as prescribed by the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), Resource Conservation and Recovery Act of 1976 (RCRA) past practice, and Atomic Energy Act of 1954 (AEA) regulatory requirements and orders.

Groundwater Chemistry and Hydrogeology of the Upper Saddle Mountains Basalt-Confined Aquifer South and Southeast of the Hanford Site

This report describes groundwater monitoring within the upper basalt-confined aquifer in areas bordering the Hanford Site to the south and southeast. The purpose of the sample was to demonstrate that constituents analyzed were within the range of background concentrations and to evaluate any potential connection between groundwater on and off the Hanford Site.

Science To Support DOE Site Cleanup: The Pacific Northwest National Laboratory Environmental Management Science Program Awards

Pacific Northwest National Laboratory (PNNL) was awarded ten Environmental Management Science Program (EMSP) research grants in fiscal year 1996, six in fiscal year 1997, nine in fiscal year 1998, seven in fiscal year 1999, and five in fiscal year 2000. All of the fiscal year 1996 award projects have published final reports. The 1997 and 1998 award projects have been completed or are nearing completion. Final reports for these awards will be published, so their annual updates will not be included in this document. This section summarizes how each of the 1999 and 2000 grants address significant U.S. Department of Energy (DOE) cleanup issues, including those at the Hanford Site. The technical progress made to date in each of these research projects is addressed in more detail in the individual progress reports contained in this document. The 1999 and 2000 EMSP awards at PNNL are focused primarily in two areas: Tank Waste Remediation, and Soil and Groundwater Cleanup.

Fiscal Year 2003 Integrated Monitoring Plan for the Hanford Groundwater Monitoring Project

This document is an integrated monitoring plan for the Groundwater Monitoring Project. It documents well and constituent lists for the monitoring required by the Atomic Energy Act of 1954 and its implementing orders.

Identification of a Hanford Waste Site for Initial Deployment of the In Situ Gaseous Reduction Approach

In Situ Gaseous Reduction is a technology currently being developed by DOE for the remediation of soil waste sites contaminated with hexavalent chromium. This document presents the results of recent characterization activities undertaken at several of the soil waste sites at Hanford that contain siginficant levels of hexavalent chromium contamination. The objective of this study is to select a site for initial deployment of the technology at the Hanford Site.

Characterization Activities Conducted at the 183-DR Site in Support of an In Situ Gaseous Reduction Demonstration

In Situ Gaseous Reduction (ISGR) is a technology developed by DOE for the remediation of soil waste sites contaminated with hexavalent chromium. This document presents information associated with characterization activities conducted at the 183-DR site at Hanford, which is associated with a significant groundwater contaminant plume and was formerly a water treatment facility that utilized chromate as a corrosion inhibitor. Geotechnical and chemical data were collected during the excavation of trenches and the drilling of two vadose zone boreholes to support a possible ISGR demonstration at 183-DR. Although elevated total chromium and trace levels of hexavalent chromium were identified from one of the trenches and one of the boreholes, it appears that the boreholes missed the vadose zone contaminant source responsible for the chromium groundwater plume located downgradient of the 183-DR site. Recommendations are provided, however, for future work at 183-DR that may serve to identify the source for the groundwater plume and possibly provide an opportunity for an ISGR demonstration.

Interfacial Reduction-Oxidation Mechanisms Governing Fate and Transport of Contaminants in the Vadose Zone

Immobilization of toxic and radioactive metals (e.g., Cr, Tc, U) in the vadose zone by In Situ Gaseous Reduction (ISGR) using hydrogen sulfide (H 2 S) is a promising technology being developed by the U.S. Department of Energy (DOE) for soil remediation. Earlier laboratory studies have shown that Cr(VI) in a number of soil samples can be effectively immobilized by treatment with diluted H 2 S. A field test has also been completed which resulted in 70% immobilization of Cr(VI). Nevertheless, detailed reaction kinetics and mechanisms for Cr(VI) immobilization are unknown in the H 2 S treatment of the vadose zone. The reaction products have not been fully characterized. The long-term metal stability after the ISGR treatment is not fully understood. The objective of this project is to seek basic scientific understandings concerning the kinetics and mechanisms of interactions among H 2 S, the metal contaminants, and soil components. Within a three-year period of the project, the following specific research tasks will be accomplished: (A) Evaluation of the potential catalytic effect of mineral surfaces on the rate of Cr(VI) reduction by H 2 S and the rate of H 2 S oxidation by air, (B) Identification of the reactions of soil minerals with H 2 S and determination of associated reaction rates, (C) Evaluation of the role of soil water chemistry on the reduction of Cr(VI) by H 2 S, (D) Assessment of the reductive buffering capacity of H 2 S-reduced soil and the potential for emplacement of long-term vadose zone reactive barriers, and (E) Evaluation of the potential for immobilization of Tc and U in the vadose zone by reduction and an assessment of the potential for remobilization by subsequent reoxidation. A substantial amount of work will be accomplished on Tasks A-D during FY2000. Task E will be completed in the FY2001-2002.