|This site is the former location of a large grain elevator located within the Argentine Yard Railroad facility. The elevator was demolished in 1996, the cement foundation covered by approximately 5 feet of rock ballast and overlaid by closely spaced railroad tracks. Burlington, Northern and Santa Fe (BNSF) conducted an environmental investigation at the site in October 1993 (Terracon) in preparation for demolition of the elevator. The analytical results from this investigation indicated the presence of high levels of carbon tetrachloride (CT) in soil and groundwater.
Another investigation was conducted in 1995 (Dames & Moore) and CT and petroleum hydrocarbons were detected in soil and in sediment and surface water collected from the storm sewer system. The source of the CT was an above ground storage tank located next to the elevator structure. Subsequent investigations (1998 and 2001, RETEC) were conducted following acceptance into the Voluntary Cleanup and Property Redevelopment Program (VCPRP) and results indicated the presence of CT, chloroform, benzene, naphthalene, total petroleum hydrocarbons (TPH), including gasoline range organics (GRO) and diesel range organics (DRO) in soil and ground water. Possible sources for the petroleum contaminants include aboveground storage tanks (ASTs) and four buried rail tank cars.
In 2004, BNSF completed the third phase (Phase 3) Voluntary Cleanup investigation activities in an attempt to complete delineation of TPH GRO and benzene groundwater contamination down gradient of the source area. Due to increases of TPH-DRO and naphthalene in groundwater, wells MW08-1 and MW08-2 were installed in 2008 along the northern property boundary under Phase IV VCI activities to delineate those impacts; three temporary monitoring wells were also installed north of Kansas Avenue. Permanent well MW09-1 was installed north of Kansas Avenue in 2009. In 2010, three monitoring wells were constructed into bedrock northeast of the source area. Additional wells were installed near the north property line in 2011 and 2013.
The groundwater monitoring frequency was reduced from a quarterly basis to a semi-annual schedule in 2015. The report for the most recent quarterly monitoring event, completed in December 2014, was approved on 5-29-15. Groundwater monitoring was suspended as AECOM, consultant for BNSF, prepared a conceptual site model / qualitative risk analysis (CSM/QRA).
A CSM/QRA was submitted on 7-22-15 which requested a no further action (NFA) determination for the site. The KDHE notified BNSF during a 12-16-15 teleconference that a NFA will not be issued at this time and this discussion is documented in a 12-16-15 comment letter for the CSM/QRA. 2. A reduced scope of work for a March 2016 groundwater monitoring event was approved on 3-2-16.
BNSF proposed a further reduction in monitoring program as was agreed during a May 2016 meeting with KDHE. As the site is an active rail yard, KDHE will allow the site to remain in the VCI phase and not require remediation at this time. The KDHE also agreed to not require further groundwater delineation north of Kansas Ave. On 8-22-16, the report associated with the March 2016 groundwater monitoring event was received. This report includes the proposed long-term monitoring (LTM) plan for the site and this document was approved on 10-7-16. Select monitoring wells will be sampled annually or once every two years during the LTM plan.
A proposal to reduce the monitoring frequency of select wells to a biennial basis was approved on 7-13-18. A report for the annual 2019 groundwater monitoring event was approved on 1-10-20.