Abiotic Degradation Rates for Carbon Tetrachloride: and Chloroform: Progress in FY 2008

PDF Version Also Available for Download.

Description

This is a letter report summarizing work performed in FY2008 to determine the rates of carbon tetrachloride hydrolysis at temperatures close to actual groundwater temperatures. The report describes the project, the methodology, and the results obtained since the project's inception in FY2006. Measurements of hydrolysis rates in homogeneous solution have been completed for temperaturs of 70 C through 40 C, with additional data available at 30 C and 20 C. These results show no difference between the rates in deionized H2O and in filter-sterilized Hanford-Site groundwater. Moreover, the rates measured are 2-3 times slower than predicted from the open literature. ... continued below

Physical Description

PDFN

Creation Information

Amonette, James E.; Jeffers, Peter M.; Qafoku, Odeta; Russell, Colleen K.; Wietsma, Thomas W. & Truex, Michael J. October 31, 2008.

Context

This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided by UNT Libraries Government Documents Department to Digital Library, a digital repository hosted by the UNT Libraries. It has been viewed 33 times . More information about this report can be viewed below.

Who

People and organizations associated with either the creation of this report or its content.

Publisher

  • Pacific Northwest National Laboratory (U.S.)
    Publisher Info: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States), Environmental Molecular Sciences Laboratory (EMSL)
    Place of Publication: Richland, Washington

Provided By

UNT Libraries Government Documents Department

Serving as both a federal and a state depository library, the UNT Libraries Government Documents Department maintains millions of items in a variety of formats. The department is a member of the FDLP Content Partnerships Program and an Affiliated Archive of the National Archives.

Contact Us

What

Descriptive information to help identify this report. Follow the links below to find similar items on the Digital Library.

Description

This is a letter report summarizing work performed in FY2008 to determine the rates of carbon tetrachloride hydrolysis at temperatures close to actual groundwater temperatures. The report describes the project, the methodology, and the results obtained since the project's inception in FY2006. Measurements of hydrolysis rates in homogeneous solution have been completed for temperaturs of 70 C through 40 C, with additional data available at 30 C and 20 C. These results show no difference between the rates in deionized H2O and in filter-sterilized Hanford-Site groundwater. Moreover, the rates measured are 2-3 times slower than predicted from the open literature. Measurements of rates involving sterile suspensions of Hanford-Site sediment in Hanford-Site groundwater, however, show faster hydrolysis at temperatures below 40 C. Extrapolation of the current data available suggests a six-fold increase in rate would be expected at groundwater temperature of 16 C due to the presence of the sediment. This result translates into a 78-year half-life, rather than the 470-680 year half-life that would be predicted from rate determinations in homogeneous solution. The hydrolysis rate data at 20 C, in contrast to those at higher temperatures, are preliminary and have low statistical power. While significant (p < 0.05) differences between the heterogeneous and homogeneous systems are seen at 30 C, the results at 20 C are not statistically significant at this level due to limited data and the very slow nature of the reaction. More time is needed to collect data at these low temperatures to improve the statistical power of our observation. Given the critical need for hydrolysis rate data at temperatures relevant to groundwater systems, we have three recommendations for future work. First, we recommend a continuation of the sampling and analysis of the remaining long-term sealed-ampule experiments described in this report. These are primarily 20 C and 30 C experiments. The data at 20°C, which are most germane to the groundwater environment, will likely take two more years before they are complete. Second, due to the importance of heterogeneous effects, we recommend the continuation of sampling and analysis for a similar set of experiments looking at hydrolysis rates of CT and CF in contact with individual minerals (montmorillonite, kaolinite, albite, and muscovite) or Hanford-Site sediment, and, for CF, in homogeneous solutions. These experiments were set up under a separate project funded by a congressional earmark (EM-22) for which funding expired at the end of FY08. Third, we strongly recommend development of a 13C/12C isotope ratio mass spectrometry (IRMS) approach for determination of hydrolysis rates at groundwater temperatures and relevant CT and CF concentrations. The technique is sensitive enough that we expect to be able to shorten the time required for a rate-constant determination by 20-fold. Thus, a 5-year experiment conducted by the sealed-ampule approach could be shortened to 3 months by the IRMS approach. This sensitivity also would allow the IRMS technique to be used to follow hydrolysis rates at concentrations found in groundwater plumes at Hanford.

Physical Description

PDFN

Language

Item Type

Identifier

Unique identifying numbers for this report in the Digital Library or other systems.

  • Report No.: PNNL-18020
  • Grant Number: AC05-76RL01830
  • DOI: 10.2172/1006330 | External Link
  • Office of Scientific & Technical Information Report Number: 1006330
  • Archival Resource Key: ark:/67531/metadc846386

Collections

This report is part of the following collection of related materials.

Office of Scientific & Technical Information Technical Reports

Reports, articles and other documents harvested from the Office of Scientific and Technical Information.

Office of Scientific and Technical Information (OSTI) is the Department of Energy (DOE) office that collects, preserves, and disseminates DOE-sponsored research and development (R&D) results that are the outcomes of R&D projects or other funded activities at DOE labs and facilities nationwide and grantees at universities and other institutions.

What responsibilities do I have when using this report?

When

Dates and time periods associated with this report.

Creation Date

  • October 31, 2008

Added to The UNT Digital Library

  • May 19, 2016, 3:16 p.m.

Description Last Updated

  • Nov. 22, 2016, 2:21 p.m.

Usage Statistics

When was this report last used?

Yesterday: 0
Past 30 days: 3
Total Uses: 33

Interact With This Report

Here are some suggestions for what to do next.

Start Reading

PDF Version Also Available for Download.

International Image Interoperability Framework

IIF Logo

We support the IIIF Presentation API

Amonette, James E.; Jeffers, Peter M.; Qafoku, Odeta; Russell, Colleen K.; Wietsma, Thomas W. & Truex, Michael J. Abiotic Degradation Rates for Carbon Tetrachloride: and Chloroform: Progress in FY 2008, report, October 31, 2008; Richland, Washington. (digital.library.unt.edu/ark:/67531/metadc846386/: accessed July 18, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.