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Title: Data Validation Package August 2015 Groundwater Sampling at the Grand Junction, Colorado, Disposal Site October 2015

Technical Report ·
DOI:https://doi.org/10.2172/1351637· OSTI ID:1351637
 [1];  [2]
  1. U.S. Dept. of Energy, Washington, DC (United States). Office of Legacy Management
  2. Navarro Research and Engineering, Inc., Oak Ridge, TN (United States)

Sampling Period: August 4, 2015. The 1998 Interim Long-Term Surveillance Plan for the Cheney Disposal Site Near Grand Junction, Colorado, requires annual monitoring to assess the performance of the disposal cell. Monitoring wells 0731, 0732, and 0733 were sampled as specified in the plan. Sampling and analyses were conducted in accordance with Sampling and Analysis Plan for the U.S. Department of Energy Office of Legacy Management Sites (LMS/PRO/S04351, continually updated). The water level was measured at each sampled well. The water level in well 0733, located in the disposal cell, is lower than water levels in adjacent wells 0731 and 0732, indicating a hydraulic gradient toward the disposal cell. Results from this sampling event were generally consistent with results from the past as shown in the attached concentration-versus-time graphs. There have been no large changes in contaminant concentration observed over the last several years with the following exception. The uranium concentration in well 0733 has been trending upward since 2003. High uranium concentrations are expected in this well because it is located in the disposal cell. The selenium concentrations observed in wells 0731 and 0732 are elevated when compared to the disposal cell 0733. Wells 0731 and 0732 are completed at the alluvium/Mancos contact; here, elevated selenium concentrations are expected due to contributions from the Mancos shale.

Research Organization:
U.S. Dept. of Energy, Washington, DC (United States). Office of Legacy Management
Sponsoring Organization:
USDOE Office of Legacy Management (LM), Office of Field Operations
DOE Contract Number:
LM0000421
OSTI ID:
1351637
Report Number(s):
S-00815
Country of Publication:
United States
Language:
English