Annual report of groundwater monitoring at Everest, Kansas in 2011.

LaFreniere, L. M. (Environmental Science Division)

关键词: AGRICULTURE;    CARBON TETRACHLORIDE;    CHLOROFORM;    CONTAMINATION;    KANSAS;    MONITORING;    NITRATES;    PLUMES;    SAMPLING;    STREAMS;    SURFACE WATERS;    TESTING;    WATER SUPPLY;    GROUND WATER;   

DOI  :  10.2172/1039147
RP-ID  :  ANL/EVS/AGEM/TR-11-11
PID  :  OSTI ID: 1039147
Others  :  TRN: US201209%%315

学科分类：环境科学（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

Everest, Kansas, is a small rural community (population approximately 300) located in the southeast corner of Brown County, in the northeastern corner of Kansas. Carbon tetrachloride and chloroform contamination in groundwater at Everest was initially identified in 1997 as a result of testing performed under the Commodity Credit Corporation/U.S. Department of Agriculture (CCC/USDA) private well sampling program conducted by the Kansas Department of Health and Environment (KDHE). The KDHE collected samples from seven private wells in and near Everest. Carbon tetrachloride and chloroform were found in only one of the wells, the Donnie Nigh domestic well (owned at that time by Tim Gale), approximately 3/8 mi northwest of the former Everest CCC/USDA facility. Carbon tetrachloride and chloroform were detected at 121 {mu}g/L and 4 {mu}g/L, respectively. Nitrate was found at 12.62 mg/L. The USDA subsequently connected the Nigh residence to the Everest public water supply system. The findings of the 2011 monitoring at Everest support the following conclusions: (1) Measurements of groundwater levels obtained manually during annual monitoring in 2009-2011 (and through the use of automatic recorders in 2002-2010) have consistently indicated an initial direction of groundwater flow from the former CCC/USDA facility to the north-northwest and toward the Nigh property, then west-southwest from the Nigh property toward the intermittent creek that lies west of the former CCC/USDA facility and the Nigh property. (2) At most of the monitored locations, carbon tetrachloride concentrations decreased in April 2011 relative to 2010 results. Noteworthy decreases of > 50% occurred at locations MW4, MW60, and MW88, in the most concentrated part of the plume. (3) Comparison of accumulated data demonstrates that the area of the carbon tetrachloride plume with concentrations > 200 {mu}g/L has decreased markedly over time and suggests a generally decreasing trend in contaminant levels. (4) The trace increases in carbon tetrachloride concentrations observed in 2010 at locations SB63 and SB64 were notable because of the locations proximity to the downgradient intermittent creek. However, these increases were not confirmed in sampling in 2011. (5) The results of the April 2011 monitoring event continue to support the interpretation, made during the 9-yr observation period from 2001 to 2010, that the migration rate for contamination in groundwater toward the intermittent creek is very slow. (6) No carbon tetrachloride was detected in five samples of surface water collected from the intermittent creek west of the former CCC/USDA facility and the Nigh property, or in tree branch tissue samples collected at locations along the banks of the creek. These observations indicate that the carbon tetrachloride contamination identified at Everest has, to date, not impacted the surface waters of the intermittent creek.