October 2007 monitoring results for Morrill, Kansas.

LaFreniere, L. M.

Argonne National Laboratory

关键词: Surface Waters;    Bioremediation;    Monitoring;    Sediments;    Ground Water;   

DOI  :  10.2172/937015
RP-ID  :  ANL/EVS/AGEM/TR-08-02
RP-ID  :  DE-AC02-06CH11357
RP-ID  :  937015

美国|其它

来源: UNT Digital Library

【 摘 要 】

In September 2005, the Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) initiated periodic sampling of groundwater in the vicinity of a grain storage facility formerly operated by the CCC/USDA at Morrill, Kansas. On the basis of available information, the CCC/USDA believes that one or more third parties operated this facility after termination of the CCC/USDA's lease in 1971. The sampling at Morrill is being performed on behalf of the CCC/USDA by Argonne National Laboratory, in accord with a monitoring program approved by the Kansas Department of Health and Environment (KDHE), to monitor levels of carbon tetrachloride contamination identified in the groundwater at this site (Argonne 2004, 2005a). Under the KDHE-approved monitoring plan (Argonne 2005b), the groundwater has been sampled twice yearly for a recommended period of two years. The samples are analyzed for volatile organic compounds (VOCs), as well as for selected geochemical parameters to aid in the evaluation of possible natural contaminant degradation (reductive dechlorination) processes in the subsurface environment. The sampling is presently conducted in a network of 12 monitoring wells and 3 private wells (Figure 1.1), at locations approved by the KDHE. The scope of the originally approved monitoring has been expanded to include vegetation sampling (initiated in October 2006) and surface water and stream bed sediment sampling (initiated in March 2007). The analytical results for groundwater sampling events at Morrill in September 2005, March 2006, September 2006, and March 2007 were documented previously (Argonne 2006a, 2007c,e). The results have demonstrated the presence of carbon tetrachloride contamination, at levels exceeding the KDHE Tier 2 Risk-Based Screening Level (5.0 {micro}g/L) for this compound, in a groundwater plume extending generally south-southeastward from the former CCC/USDA facility, toward Terrapin Creek at the south edge of the town. Little clear pattern of change in the concentrations observed at the individual monitoring points and little plume migration have been observed in previous monitoring events. Low levels ({le} 1.3 {micro}g/L) of carbon tetrachloride have persistently been detected at monitoring well MW8S, however, along an intermittent tributary to Terrapin Creek. This observation suggests a possible risk of contamination of the surface waters of the creek. In light of these findings, in 2006 the CCC/USDA recommended expansion of the approved monitoring program to include the collection and analysis of surface water samples along Terrapin Creek (Argonne 2007e). At the request of the KDHE (KDHE 2007a), locations for both surface water and shallow sediment sampling were discussed with the KDHE in January 2007. An addendum to the existing monitoring plan and a standard operating procedure (SOP AGEM-15) for sediment sampling were submitted to the KDHE on the basis of these discussions (Argonne 2007a,b). This report presents the results of groundwater, surface water, and sediment sampling performed at Morrill in October 2007, in accord with the monitoring plan (Argonne 2005b) and the addendum to that plan (Argonne 2007a). To supplement these studies, Argonne also sampled natural vegetation along Terrapin Creek in October 2006, April 2007, and July 2007 for analyses for VOCs. The results of the plant tissue analyses are included in this report. The October 2007 groundwater sampling at Morrill represents the fifth and final monitoring event performed under the recommended two-year monitoring program approved by the KDHE.