Analyses of Water and Rock Samples

The water samples were shipped to four U.S. Geological Survey (USGS) laboratories depending on the type of analysis required. The types of analyses and the laboratories used are summarized in table 2. Water samples collected for major dissolved ions, aluminum, boron, and low-level nutrients were sent the USGS National Water Quality Laboratory (NWQL) in Lakewood, Colorado. Water samples collected for stable isotopes of hydrogen and oxygen were sent to the USGS Reston Stable Isotope Laboratory (RSIL) in Reston, Virginia. Water samples collected for dissolved gases and chlorofluorocarbons were sent to the USGS Chlorofluorocarbon (CFC) Laboratory in Reston, Virginia. Water and rock samples for strontium, strontium isotope ratio (⁸⁷Sr/⁸⁶Sr), dissolved inorganic carbon, and stable carbon isotopes (¹³C and ¹²C) were sent to the Yucca Mountain Project Environmental Laboratory in Lakewood, Colorado.

Results of all analyses done by the different laboratories are stored in the USGS National Water Information System (NWIS) database (http://waterdata.usgs.gov/nv/nwis/nwis). The analytical procedures used by the NWQL are available at http://nwql.cr.usgs.gov/usgs/catalog/index.cfm. Analytical procedures used by the RSIL are available at http://isotopes.usgs.gov/Methods.htm and analytical procedures used by the CFC Laboratory are available at http://water.usgs.gov/lab. Sampling and analytical procedures used by the Yucca Mountain Project Environmental laboratory for analyzing strontium concentrations and strontium ratios in water and rock are described in Paces and others (2007). Procedures for analyzing total dissolved inorganic carbon and stable carbon isotopes in water are listed in two technical procedures of the Yucca Mountain Project as part of the U.S. Department of Energy’s requirements for quality assurance and quality control (R.L. Moscati, U.S. Geological Survey, Lakewood, Colorado, written commun., 2007). Procedures for analyzing stable carbon and oxygen isotopes in rock are listed in a third technical procedures manual (R.L. Moscati, U.S. Geological Survey, Lakewood, Colorado, written commun., 2007).

Because of the limited number of samples collected, no field blanks were analyzed. However, all laboratories used to analyze the water samples have been quality assured. Standard laboratory procedures for quality assurance at the NQWL are documented by Pirkey and Glodt (1998) and Maloney (2005). Standard procedures for quality assurance at the RSIL are documented at http://isotopes.usgs.gov/Quality.htm. Duplicate samples (two each for dissolved gases and five each for chlorofluorocarbon analyses) were sent to the CFC laboratory as part of their quality-assurance procedure. Multiple tests of the samples were done on the samples sent to the laboratory. Only one sample from the permanent pool in Lehman Caves differed greatly from two other duplicate samples for analysis of CFC‑11, but CFC‑11 concentrations were greater than the current concentration in the atmosphere in all three samples collected at this location.