Groundwater geochemical and selected volatile organic compound data, Operable Unit 1, Naval Undersea Warfare Center, Division Keyport, Washington, July 2015

Data Series 998
Prepared in cooperation with Department of the Navy, Naval Facilities Engineering Command, Northwest
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Abstract

Previous investigations indicate that concentrations of chlorinated volatile organic compounds (CVOCs) are substantial in groundwater beneath the 9-acre former landfill at Operable Unit 1, Naval Undersea Warfare Center, Division Keyport, Washington. The U.S. Geological Survey has continued to monitor groundwater geochemistry to ensure that conditions remain favorable for contaminant biodegradation as specified in the Record of Decision for the site.

This report presents groundwater geochemical and selected CVOC data collected at Operable Unit 1 by the U.S. Geological Survey during July 6–8 and July 31, 2015 in support of long-term monitoring for natural attenuation. Water samples were collected from 13 wells, 9 piezometers, and 13 shallow groundwater passive-diffusion sampling sites in the nearby marsh. Samples from all wells and piezometers were analyzed for oxidation-reduction (redox) sensitive constituents. Samples from all piezometers and four wells also were analyzed for CVOCs and dissolved gases, as were all samples from the passive-diffusion sampling sites. 

In 2015, concentrations of redox-sensitive constituents measured at all wells and piezometers were consistent with those measured in previous years, with dissolved oxygen concentrations all less than 1 milligram per liter; little to no detectable nitrate; abundant dissolved manganese, iron, and methane; and commonly detected sulfide. In the upper aquifer of the northern plantation in 2015, CVOC concentrations at all piezometers were similar to those measured in previous years, and concentrations of the reductive dechlorination byproducts ethane and ethene were equivalent to the concentrations measured in 2014. In the upper aquifer of the southern plantation, CVOC concentrations measured in piezometers during 2015 continued to be variable as in previous years, and often very high, and reductive dechlorination byproducts were detected in one of the three wells and in piezometers. Beneath the marsh adjacent to the southern plantation, CVOC concentrations measured in 2015 continued to vary spatially and temporally, and were high. The total CVOC concentration, at what have been historically the most contaminated passive-diffusion sampler sites (S-4 T, S-4B T, and S-5 T), continued elevated trends, as did one of the new sampler sites (S-9 T) installed in 2015. For the intermediate aquifer in 2015, concentrations of reductive dechlorination byproducts ethane and ethene and CVOCs were consistent with those measured in previous years.

Suggested Citation

Huffman, R.L., 2016, Groundwater geochemical and selected volatile organic compound data, Operable Unit 1, Naval Undersea Warfare Center, Division Keyport, Washington, July 2015: U.S. Geological Survey Data Series 998, 55 p., http://dx.doi.org/10.3133/ds998.

ISSN: 2327-638X (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Sample Collection and Analysis
  • Selected Monitoring Data
  • Summary
  • References
  • Appendix A

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Groundwater geochemical and selected volatile organic compound data, Operable Unit 1, Naval Undersea Warfare Center, Division Keyport, Washington, July 2015
Series title Data Series
Series number 998
DOI 10.3133/ds998
Year Published 2016
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Washington Water Science Center
Description iv, 55 p.
Country United States
State Washington
Other Geospatial Division Keyport
Online Only (Y/N) Y
Additional Online Files (Y/N) N