Ambient changes in tracer concentrations from a multilevel monitoring system in Basalt

Groundwater Monitoring & Remediation
By: , and 



Starting in 2008, a 4-year tracer study was conducted to evaluate ambient changes in groundwater concentrations of a 1,3,6-naphthalene trisulfonate tracer that was added to drill water. Samples were collected under open borehole conditions and after installing a multilevel groundwater monitoring system completed with 11 discrete monitoring zones within dense and fractured basalt and sediment layers in the eastern Snake River aquifer. The study was done in cooperation with the U.S. Department of Energy to test whether ambient fracture flow conditions were sufficient to remove the effects of injected drill water prior to sample collection. Results from thief samples indicated that the tracer was present in minor concentrations 28 days after coring, but was not present 6 months after coring or 7 days after reaming the borehole. Results from sampling the multilevel monitoring system indicated that small concentrations of the tracer remained in 5 of 10 zones during some period after installation. All concentrations were several orders of magnitude lower than the initial concentrations in the drill water. The ports that had remnant concentrations of the tracer were either located near sediment layers or were located in dense basalt, which suggests limited groundwater flow near these ports. The ports completed in well-fractured and vesicular basalt had no detectable concentrations.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Ambient changes in tracer concentrations from a multilevel monitoring system in Basalt
Series title Groundwater Monitoring & Remediation
DOI 10.1111/gwmr.12038
Volume 34
Issue 1
Year Published 2014
Language English
Publisher Wiley
Contributing office(s) Idaho Water Science Center
Description 10 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Groundwater Monitoring & Remediation
First page 79
Last page 88
Country United States
State Idaho
Other Geospatial Idaho National Laboratory
Datum North American Datum of 1927
Projection Universal Transverse Mercator Projection
Scale 100000
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