STP1118: Assessing the Usability of Historical Water-Quality Data for Current and Future Applications

    Spreizer, GM
    Senior ScientistsEngineering Geologist, Geraghty & Miller, IncAndover, MA officeCity of Industry, CA officeSouthern California Edison,

    Calabrese, TJ
    Senior ScientistsEngineering Geologist, Geraghty & Miller, IncAndover, MA officeCity of Industry, CA officeSouthern California Edison,

    Weidner, RS
    Senior ScientistsEngineering Geologist, Geraghty & Miller, IncAndover, MA officeCity of Industry, CA officeSouthern California Edison,

    Pages: 14    Published: Jan 1992


    Abstract

    Large amounts of laboratory data have been generated as part of environmental investigations, and particularly ground-water investigations conducted during the 1970s and 1980s. These data present a historical water-quality record at a facility by representing, in many cases, the baseline ground-water quality, and changes in water quality due to degradational processes and remedial activities.

    Ground-water chemistry data collected during the 1970s and 1980s were often generated using laboratory quality assurance/quality control (QA/QC) procedures considered inadequate by today's standards. In addition, the documentation required to support the quality of the laboratory data may be unavailable. The absence of the supporting QA/QC documentation or the use of different QA/QC procedures than those used today should not be the basis for removal of the data from the facility's ground-water quality database. In a large number of cases, the historical data are “good data.” Historical water-quality data are useful and should be available for use in the design of ground-water monitoring programs, for the selection and design of remedial measures, and to monitor the effectiveness of past and anticipated future remedial activities.

    This paper presents a series of techniques that, when used together, can demonstrate the usability of a historical water-quality database where laboratory QA/QC data are unavailable. This paper makes an important assumption that there is a difference between data usability and data validation. The assessment of the usability of a database is performed as a two-part exercise. The first step is to conduct a qualitative pattern recognition procedure and the second is to use more stringent statistical procedures to identify if the data are presenting a consistent description of the ground-water system. This data-usability technique has been successfully applied at a site in California. The results of this case study are also present in this paper.

    Keywords:

    Data usability, data validation, statistics, pattern recognition, historical water-quality, regression analysis, graphical representations, California, pentachlorophenol, remedial programs


    Paper ID: STP19141S

    Committee/Subcommittee: D18.95

    DOI: 10.1520/STP19141S


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