Groundwater Sampling and Soil Gas Data Analysis, Distler Brickyard Superfund Site, Hardin County, Kentucky -- June - August 2000

Martin, Jennifer Pauline ; Peterson, Lance Nutting ; Taylor, C. J.

Idaho National Laboratory

关键词: Data Analysis;    Removal;    Superfund Site;    Saturation;    Us Superfund;   

DOI  :  10.2172/911207
RP-ID  :  INEEL/EXT-00-01419
RP-ID  :  DE-AC07-99ID-13727
RP-ID  :  911207

美国|英语

来源: UNT Digital Library

【 摘 要 】

This report describes the results of groundwater and soil gas sampling conducted at the Distler Brickyard Site, Hardin County, Kentucky, June-August, 2000. The purpose of the sampling activities was to address remaining data gaps regarding the feasibility of monitored natural attenuation (MNA) for remediation of chloroethene/ane contamination. Specifically, data gaps fall into four categories: 1) effect of seasonal recharge on contaminant concentrations, 2) geochemical conditions in the Fine Grained Alluvium (FGA), 3) conditions along the flowpath between Wells GW-11 and MW-3, and 4) the extent of aerobic degradation in the Coarse Grained Alluvium (CGA). A data collection strategy composed of both groundwater sampling and passive soil vapor sampling devices (Gore-Sorbers?) was used. The Gore-Sorber? technology was used to collect data from the FGA, which because of its low hydraulic conductivity and variable saturation makes collection of groundwater samples problematic. Gore-Sorbers were deployed in 15 wells, most of them being in the FGA, and groundwater samples were collected in 17 wells, which were mostly in the CGA. Both sampling methods were utilized in a subset of wells (7) in order to determine the general comparability of results obtained from each method. Results indicate that water levels in both the FGA and CGA were higher in June-August 2000 than in October 1999, likely due to increased infiltration of precipitation through the FGA during the wetter months. Redox conditions in the FGA and downgradient CGA were iron-reducing, less reducing than in October-1999. In general, concentrations of chloroethenes/anes were higher in June-August 2000 than October 1999. Trichloroethene (TCE) was present at concentrations as high as 65 µg/L in the FGA and 19 µg/L in the CGA. This is substantially higher than the maximum concentration in October 1999 of 11 µg/L. The following conclusions were drawn from these data collection activities: 1) two potential contaminant source areas remain at the site, 2) redox conditions are less reducing than October 1999, 3) anaerobic reductive dechlorination (ARD) continues to take place in the FGA, and 4) seasonal fluctuations in recharge affect water levels, redox conditions, contaminant concentrations, and ARD reactions. Possible final remedial response actions include 1) monitored natural attenuation, 2) monitored natural attenuation with physical source removal, or 3) monitored natural attenuation with source removal via enhanced ARD. All of these remedies will require the collection of additional data in three areas: 1) the nature and extent of the GW-3/UDBW-11 source area and the flux rate and fate of contaminants from it, 2) the magnitude and timing of recharge fluctuations, and 3) the local hydraulic gradient and groundwater flow directions. Each remedy may also have specific additional data collection requirements. This document will serve as the basis for the selection of the appropriate remedy by the state and federal regulators.