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5 Monitoring and Data Quality
Pages 49-62

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From page 49...
... LANL's understanding of contaminant pathways, which is essential for developing a monitoring plan, Well coNsTrUcTioN is discussed in Chapter 4. The data-quality questions raised in the committee's LANL will continue to construct water wells for at least task statement are: three purposes.
From page 50...
... , and their drilling boundaries, and near-source wells to monitor contractors to install the deep wells into the regional aquifer known contaminant movement or demonstrate the (R-wells) required by the Hydrogeologic Workplan.
From page 51...
... This geophysical testing provided information Workplan. to establish locations of the higher-permeability zones by characterizing the subsurface lithologic units in terms of their Development moisture content (including perched groundwater)
From page 52...
... SIDEBAR 5.1 Geophysical Testing to Position Well Screens Downhole geophysical tools are often applied in hydrogeologic characterization programs to identify changes in lithology indicated by mineralogical, permeability, and porosity variations. The extensive suite of geophysical testing done on most R-wells included nearly continuous measurements along the length of the borehole to measure the following:a • Total and effective water-filled porosity and pore size distribution, for estimation of hydraulic conductivity, • Bulk density considering both water- and air-filled porosity, • Bulk electrical resistivity at multiple depths, • Bulk concentrations of selected mineral-forming elements, • Spectral natural gamma-ray emissions, • Bedding orientation and geologic texture, • Acoustic compressional wave velocity, • Borehole azimuth and inclination, and • Borehole diameter.
From page 53...
... However, it is a significant change from rent groundwater monitoring network by area (e.g., TA-21, LANL's presentations to the committee, which emphasized TA-54, Mortandad Canyon)
From page 54...
...  PLANS AND PRACTICES FOR GROUNDWATER PROTECTION AT THE LOS ALAMOS NATIONAL LABORATORY FIGURE 5.2 Reactive contaminant capture barrier. Geologist Robert Gilkeson described concepts of how drilling fluids could form a zone that removes contaminants from sampled groundwater.
From page 55...
... In this context, the committee made general observations as detailed geologic and hydrologic characterization of the that may be useful to LANL in constructing new wells during approximately 800 to 1000 feet of vadose zone, and charac- the remainder of its groundwater protection program. terization at greater depths within the regional aquifer.
From page 56...
... especially in the regional aquifer. The most trustworthy sam pling technique includes purging three or more well volumes from the monitoring well before sample collection (ASTM, Screening and Purging the Screens 1992)
From page 57...
... ; ER2004- R0) , Controlled Document signed May 8, 2006 012; April 15, 2004 Specific sampling and analytical procedures 2006 Integrated Groundwater Monitoring Plan Interim Measures Work Plan for Chromium for Los Alamos National Laboratory (LANL, Contamination in Groundwater (LANL, 2006d)
From page 58...
... in the Integrated reproducible within a laboratory or between laboratories. Groundwater Monitoring Plan (LANL, 2006a)
From page 59...
... Notably, 1.1 pCi/L is below the PQL for cleanup criterion is 0.00064 µg/L while the MDL range is Cs-137 that LANL cites elsewhere -- 8 pCi/L in the Inte- 0.0875-0.4165 µg/L and the PQL is 0.5 µg/L. grated Groundwater Monitoring Plan (Table C-4)
From page 60...
... and to ensure reliable monitoring activities in the future. The committee received little scientific information -- for Recommendation: LANL should plan and conduct future example, on a par with LANL's publications about vadose characterization drilling and monitoring well drilling as zone pathways (VZJ, 2005)
From page 61...
... is an important step in establishing lev Recommendation: LANL should ensure that there is els of naturally occurring contamination in the regional consistency and clarity of all related sampling and ana aquifer, although some gaps were identified by the com lytical procedures with documented follow-through and mittee. The Integrated Groundwater Monitoring Plan appropriate action.


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