Microelectrode Geochemcial Observatory for In Situ Monitoring of Metals Concentration and Mobility in Contaminated Sediments
Abstract
The project objective was to demonstrate and validate the Analytical Instrument Systems, Inc. (AIS) microelectrode geochemical observatory (MGO) for the long-term monitoring of metals in contaminated sediments, including a laboratory phase and a pre-field deployment at Old Woman Creek (OWC) in Huron, OH. It became clear early on that adapting this open water technology for sediments application remains a challenge. Gold-mercury amalgam electrodes, built following a design from literature, were able to detect Fe, Mn, and reduced sulfur compounds, but not the Bremerton, WA site target metals: As, Cd, Cu, Pb, Hg, Zn. Five-mm gold electrodes fabricated following procedures from literature produced calibration curves for Cu, Pb, and Zn in standard solutions and for Pb and Zn in site porewater. Attempts to ruggedize the gold electrode proved futile as the gold wire was exceptionally fragile. Because OWC sediments contain mainly Mn and Fe, the MGO was deployed with the amalgam electrode. After a few days, the MGO began intermittently shutting down. The electrode fouled over a few weeks and produced incoherent, noisy scans. Further work is needed to design a rugged electrode with the required functionality across a broad range of metals that will support a field deployable probe. A refined field design will yield cost savings via alternative power sources, such as solar, and remote data collection capability.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2013
- Accession Number
- ADA637444
Entities
People
- Amy Dindal
- Brian Yates
- Joe Voyles
- Nancy E. Ruiz
- Ryan Fimmen
- Vivek Lal
- Yu-ping Chin
Organizations
- Naval Facilities Engineering Systems Command