October 2008 monitoring results for Morrill, Kansas.

LaFreniere, L. M.

Argonne National Laboratory

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

DOI  :  10.2172/950207
RP-ID  :  ANL/EVS/AGEM/TR-09-03
RP-ID  :  DE-AC02-06CH11357
RP-ID  :  950207

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. 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 2005), to monitor levels of carbon tetrachloride contamination identified in the groundwater at this site (Argonne 2004, 2005a). This report provides results for the most recent monitoring event, in October 2008. Under the KDHE-approved monitoring plan (Argonne 2005b), groundwater was initially sampled twice yearly for a period of two years (in fall 2005, in spring and fall 2006, and in spring and fall 2007). The samples were 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. During the two-year period, the originally approved scope of the monitoring was expanded to include vegetation sampling (initiated in October 2006) and surface water and stream bed sediment sampling (initiated in March 2007, after a visual reconnaissance along Terrapin Creek [Argonne 2007a]). The analytical results for groundwater sampling events at Morrill in September 2005, March and September 2006, March and October 2007, and April 2008 were documented previously (Argonne 2006a,b, 2007b, 2008a,c). Those results consistently 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. Low levels ({le} 1.3 {micro}g/L) of carbon tetrachloride were persistently detected at monitoring well MW8S on the bank of an intermittent tributary to Terrapin Creek. This observation suggested a possible risk of contamination of the surface waters of the creek. That concern became the driving force for ongoing monitoring and consideration of possible remedial options for Morrill. In light of the early 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 2006a). At the request of the 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 2007c,d). To supplement the original scope of the monitoring, Argonne also sampled natural vegetation along Terrapin Creek in October 2006, April 2007, and July 2007 for analyses for VOCs. The results of these plant tissue analyses were reported previously (Argonne 2008a). The October 2008 sampling event reported here represents a continuation of the two-year monitoring program, as requested by the KDHE (2007b). The groundwater sampling is presently conducted, in accord with the monitoring plan (Argonne 2005b) and the addendum to that plan (Argonne 2007a), in a network of 12 monitoring wells and 3 private wells (Figure 1.1), at locations approved by the KDHE.