SYMPOSIA PAPER Published: 01 January 1992

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


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.

Author Information

Spreizer, GM
Southern California Edison
Calabrese, TJ
Southern California Edison
Weidner, RS
Southern California Edison
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Developed by Committee: D18
Pages: 377–390
DOI: 10.1520/STP19141S
ISBN-EB: 978-0-8031-5182-6
ISBN-13: 978-0-8031-1462-3