Improved Understanding of Sources of Variability in Groundwater Sampling for Long-Term Monitoring Programs
ER-1705
Objective
The Department of Defense (DoD) currently spends approximately $150 to $160 million annually for monitoring contaminated groundwater. The objectives of these monitoring programs are to guard against the migration of contaminants away from the defined areas of impact (i.e., protect receptors) and to monitor the progress of groundwater remediation programs. However, variability in groundwater monitoring data is often high, making it more difficult to achieve these monitoring objectives because it becomes harder to identify spatial and temporal trends in the data. Data quality objectives for groundwater monitoring programs typically include limits on the acceptable level of analytical variability (as characterized by laboratory duplicate samples) and field sampling variability (as characterized by field duplicate samples). However, practitioners typically accept high variability associated with other factors as inherent to groundwater monitoring. A better understanding of the sources of variability in groundwater monitoring is required to develop monitoring methods that minimize this variability and/or improved data analysis tools that control this variability.
The objective of this project is to identify key sources of variability that influence volatile organic compound (VOC) concentration measurements in water samples collected from groundwater monitoring wells using current sampling and analysis techniques. The hypotheses are that (1) in addition to sample collection and analytical methods, other specific sources of monitoring variability such as aquifer and well dynamics can be identified and quantified and (2) the variability attributable to many of the specific sources can be reduced through the use of new tools or the modification of common well sampling methods.
Technical Approach
This project is designed to obtain existing groundwater monitoring datasets supplemented by additional data collection efforts that can be analyzed to quantify the relative contribution of various sources of variability in groundwater monitoring results. The important sources are expected to include signal variability, sample collection and handling, aquifer and well characteristics, and laboratory analysis. Researchers will evaluate existing DoD groundwater monitoring datasets to identify key parameters that contribute to sampling variability. A supplemental field sampling program will be undertaken to field validate the identified variability sources and to fill data gaps encountered during data mining. The effectiveness of engineered methods to reduce variability in groundwater monitoring results will be evaluated in the field.
Benefits
High variability in groundwater monitoring datasets increases the number of monitoring locations and samples required to identify trends and achieve the goals of the monitoring program. If sources of monitoring variability can be identified and quantified, then this variability can be controlled either through modified monitoring approaches or improved data analysis techniques. This, in turn, will reduce the amount of monitoring data required to achieve the monitoring goals and improve the ability to identify spatial and temporal trends in the monitoring data. (Anticipated Project Completion - 2012)
Points of Contact
Principal Investigator
Dr. Charles Newell
GSI Environmental Inc.
Phone: 713-522-6300
Fax: 713-522-8010
Document Types
- Fact Sheet - Brief project summary with links to related documents and points of contact.
- Final Report - Comprehensive report for every completed SERDP and ESTCP project that contains all technical results.
- Cost & Performance Report - Overview of ESTCP demonstration activities, results, and conclusions, standardized to facilitate implementation decisions.
- Technical Report - Additional interim reports, laboratory reports, demonstration reports, and technology survey reports.
- Guidance - Instructional information on technical topics such as protocols and user’s guides.
- Workshop Report - Summary of workshop discussion and findings.
- Multimedia - On demand videos, animations, and webcasts highlighting featured initiatives or technologies.
- Model/Software - Computer programs and applications available for download.
- Database - Digitally organized collection of data available to search and access.