Investigation of Hexavalent Chromium Flux to Groundwater at the 100-C-7:1 Excavation Site

Truex, Michael J. ; Vermeul, Vincent R. ; Fritz, Brad G. ; Mackley, Rob D. ; Horner, Jacob A. ; Johnson, Christian D. ; Newcomer, Darrell R.

关键词: chromium;    flux;    groundwater;   

DOI  :  10.2172/1063737
RP-ID  :  PNNL-21845
RP-ID  :  RPT-DVZ-AFRI-005
PID  :  OSTI ID: 1063737
Others  :  Other: 830403000

美国|英语

来源: SciTech Connect

【 摘 要 】

Deep excavation of soil has been conducted at the 100-C-7 and 100-C-7:1 waste sites within the 100-BC Operable Unit at the Department of Energy (DOE) Hanford Site to remove hexavalent chromium (Cr(VI)) contamination with the excavations reaching to near the water table. Soil sampling showed that Cr(VI) contamination was still present at the bottom of the 100-C-7:1 excavation. In addition, Cr(VI) concentrations in a downgradient monitoring well have shown a transient spike of increased Cr(VI) concentration following initiation of excavation. Potentially, the increased Cr(VI) concentrations in the downgradient monitoring well are due to Cr(VI) from the excavation site. However, data were needed to evaluate this possibility and to quantify the overall impact of the 100-C-7:1 excavation site on groundwater. Data collected from a network of aquifer tubes installed across the floor of the 100-C-7:1 excavation and from temporary wells installed at the bottom of the entrance ramp to the excavation were used to evaluate Cr(VI) releases into the aquifer and to estimate local-scale hydraulic properties and groundwater flow velocity.