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Open-File Report 2007-1430

Open-File Report 2007-1430

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Appendix A. Quality Assurance and Control of U.S. Geological Survey 2006 Geochemical Sampling

Quality assurance and control of geochemical sampling included the collection of duplicate and field blank samples for selected redox-sensitive analytes and volatile organic compounds (VOCs). Field blanks were collected by pumping VOC-free water through previously used and cleaned tubing to determine possible sampling contamination in samples collected at known contaminated wells only; new tubing was used to sample from wells that were known to be uncontaminated or slightly contaminated and from piezometers sampled for the first time. Complete laboratory quality assurance and control data from Severn-Trent Laboratories is on file with the USGS office in Tacoma, Washington.

Duplicate sample results compared favorably for all constituents (Appendix table A1). A duplicate sample was collected and analyzed by NWQL for organic carbon, manganese, nitrate and nitrite, sulfate, chloride, ethene, and ethane for well MW1-4. The duplicate results for these constituents agreed within 10 percent. A duplicate sample was collected and analyzed for piezometer P1-7 and the chlorinated VOC concentrations agreed within 15 percent (table 3).

Chloroethenes, chloroethanes, and benzene, toluene, ethylbenze, and xylene (BTEX) were not detected in the field blank sample of pumped VOC-free water (site P1-39FB). No ethene, ethane, or chloroethene or choroethane compounds of interest were detected in the laboratory method blanks.

Table A1. Quality assurance data collected by the U.S. Geological Survey at Operable Unit 1, Naval Undersea Warfare Center, Division Keyport, Washington, 2006.

[Study site No.: Location of study sites are shown in figure 2. MW, monitoring well; P, piezometer. D denotes duplicate sample; FB denotes field blank sample. Volatile organic compounds (VOCs): PCE, tetrachloroethene; TCE, trichloroethene; cis-DCE, cis-1,2-dichloroethene; trans-DCE, trans-1,2-dichloroethene; VC, vinyl chloride; TCA, 1,1,-trichloroethane; 1,1-DCA, 1,1-dichloroethane, 1,1-DCE, 1,1-dichloroethene; CA, chloroethane; BTEX, benzene, toluene, ethylbezene, and xylene; CVOCs, sum of all chloroethenes and chloroethane concentrations shown in table. Abbreviations: mg/L, milligram per liter; nd, not detected; µg/L, microgram per liter; nd, not detected. Symbols: <, actual value is less than the value shown; –, not analyzed]

Study site No. Date sampled PCE (µ/L) TCE (µg/L) cis-DCE(µg/L) trans-DCE(µg/L) VC (µg/L) Ethane(µg/L) Ethene(µg/L) 1,1,1-TCA(µg/L) 1,1-DCA (µg/L) CA (µg/L) 1,1-DCE (µg/L)
P1-7 06-13-06 <2,000 24,000 43,000 <2,000 3,800 44 400 <2,000 <2,000 <4,000 <2,000
P1-7D 06-13-06 <2,000 28,000 48,000 <2,000 4,200 <2,000 <2,000 <4,000 <2,000
MW1-4 06-13-06 39 200
MW1-4D 06-33-06 35 180
MW1-39FB 06-14-06 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <2.0 <1.0
Study site No. Date sampled Total Dissolved oxygen (mg/L) Filtered NO2 + NO3(mg/L) Dissolved organic carbon, filtered(mg/L) Manga-nese, filtered (mg/L) Iron (II), filtered (mg/L) Sulfate, filtered (mg/L) Sulfide, unfiltered (mg/L) Dissolved methane (mg/L) Dissolved carbon dioxide (mg/L) Chloride, filtered (mg/L)
BTEX (µg/L) CVOCs (µg/L)
P1-7 06-13-06 nd 70,800 0.5 <0.06 7.6 2.0 1.82 20.2 <0.01 2.1 48.8
P1-7D 06-13-06 nd
MW1-4 06-13-06 .1 <.06 3.9 .79 .19 5.7 .01 2.1 30 19.6
MW1-4D 06-13-06 .1 <.06 3.6 .77 .19 5.7 .02 1.9 35 19.8
MW1-39FB 06-06-06 nd nd <.06 .2 <.006 <.2 <.20

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