Innovative use of a microbial tracer for measuring groundwater through a fractured matrix

Journal Article · Fri Sep 01 04:00:00 EDT 1995 · Ground Water

OSTI ID:122432

Strong-Gunderson, J M ^[1]

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1. Oak Ridge National Lab., TN (United States). Environmental Sciences Div.

Site characterization for ground water remediation activities is limited by the one`s ability to visualize the complexity of the subsurface environment. Currently, a variety of dyes, colloids, gases, etc., are used to monitor and estimate ground water flow and contaminant transport. The author has recently identified a new, innovative colloidal tracer that is a non-hazardous bacterium that is detectable at very low concentrations (ng/kg), and can provide real-time analysis (3--5 min) for measuring colloid transport. The tracer is the ice nucleating active (INA) bacterium Pseudomonas syringae. The assay conditions require measuring the freezing point of the sample (e.g., ground water and soil slurries). Typically, 10--100 {micro}L drops of water will not freeze until {minus}15 to {minus}20 C. However, if the tracer is present the water will freeze at {minus}3 to {minus}7 C. This increase in the freezing point can only be due to the presence of the tracer and this phenomenon is well documented in the plant pathology and low-temperature biology literature but has only now been applied to site characterization and remediation activities. Laboratory experiments have identified the stability of the tracer in the presence of a variety of ground water contaminants (> 100 ppm) and it is stable over a pH range of 2.3--10.0. The tracer has been demonstrated in conjunction with other commonly used tracers at a variety of field sites: (1) a drilling tracer to identify potential cross contamination, and as a colloid/bacterial tracer in (2) a hydrofracturing demonstration, (3) a horizontal recirculation well system, (4) a fractured karst matrix, and (5) a radioactive contaminated site. The data from these demonstrations have provided additional information about site characteristics including faster ground water flow rates than previously identified and due to its low sensitivities better distribution into a clay matrix than estimated by the bromide tracer.

• OSTI ID: 122432
• Report Number(s): CONF-9510211--
• Journal Information: Ground Water, Journal Name: Ground Water Journal Issue: 5 Vol. 33; ISSN GRWAAP; ISSN 0017-467X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
BIOASSAY
ENVIRONMENTAL TRANSPORT
GEOLOGIC FRACTURES
GROUND WATER
MEASURING METHODS
POLLUTANTS
RADIOACTIVE MATERIALS
REMEDIAL ACTION
SITE CHARACTERIZATION
TECHNOLOGY ASSESSMENT