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CAPSTONE REPORT ON THE APPLICATION, MONITORING, AND PERFORMANCE OF PERMEABLE REACTIVE BARRIERS FOR GROUND-WATER REMEDIATION: VOL. 2 LONG-TERM MONITORING OF PRBS: SOIL AND GROUND WATER SAMPLING
Citation:
Paul*, C J., M S. McNeil*, F P. Beck*, P J. Clark*, R T. Wilkin*, AND R W. Puls*. CAPSTONE REPORT ON THE APPLICATION, MONITORING, AND PERFORMANCE OF PERMEABLE REACTIVE BARRIERS FOR GROUND-WATER REMEDIATION: VOL. 2 LONG-TERM MONITORING OF PRBS: SOIL AND GROUND WATER SAMPLING. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-03/045b, 2003.
Impact/Purpose:
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Description:
This report discusses soil and ground-water sampling methods and procedures used to evaluate the long-term performance of permeable reactive barriers (PRBS) at two sites, Elizabeth City, NC, and the Denver Federal Center near Lakewood, CO. Both PRBs were installed in 1996 and have been monitored and studied since installation to determine their continued effectiveness for removing contaminants from ground water. An effective monitoring program requires appropriate soil and ground-water sampling techniques.
For ground-water sampling, water quality indicator parameters must be monitored to determine when formation water has been accessed. Geochemical parameters include oxidation-reduction potential (ORP), pH, specific conductance, dissolved oxygen (DO), and turbidity. Field analytical methods are discussed along with interferences and issues which may arise when using certain electrodes or instrumentsinthefield. Detailedfieldanalyticalproceduresforhexavalentchromium, ferrous iron, alkalinity, hydrogen sulfide, and dissolved oxygen are described. Also included are laboratory methods for sample analyses for organics, cations, anions, and carbon. Sample collection methods, sample containers, preservation methods, and sample storage techniques are also discussed.
An effective soil sampling program also depends on methods employed to collect, preserve, and characterize solid materials. Core samples from the PRBs were collected to assess the distribution of mineral and biomass concentrations. Proper use of a conductivity probe to verify the exact position of the iron/aquifer interface prior to collecting core material is described, along with core collection methods. Laboratory methods for core processing prior to analyses are also detailed. Procedures for inorganic carbon, sulfur, and X-ray diffraction analyses, electron microscropy, and microbial characterization are discussed in detail. In order to properly evaluate PRBs for long term performance, proper sampling methods and procedures must be employed, both in the field and in the laboratory, to provide accurate and representative soil and ground water data. Proper analytical and quality control (QC) procedures are also necessary to ensure accurate and representative data for PRB evaluation and site assessment.