US Army Corps of Engineers, Kansas City District
Under our HTRW contract with the Kansas City District of USACE, Avatar conducted a Remedial Investigation of the Former Schilling AFB Atlas F Missile Facility S-1, a FUDS located in Ottawa County, Kansas. Project included:
- Geological investigation
- Soil and groundwater investigation
- Contaminant fate and transport
- Human health risk assessment
- Environmental chemistry data collection, management, and interpretation
The Former Schilling Air Force Base Facility S-1 Site is one of 12 Atlas F missile launch facilities constructed between 1961 and 1963 within a 35-mile radius of the Former Schilling Air Force Base (SAFB) in Salina, Kansas. All required project planning documents including a UFP-QAPP, a risk assessment workplan and health and safety plans were developed prior to fieldwork. Plans were approved by the Kansas City District PDT and the Kansas Department of Health and Environment (KDHE) with very little revisions. It was determined based on historical sample results and experiences at similar sites that TCE contamination in groundwater was the primary site concern. One of the challenges with this RI was that a regional rural water authority was in the process of an assessment of the area surrounding the Site to determine the suitability of conditions for the development of an expansion well field to supplement their current water supply facilities. All relevant site information was shared with the water authority to assist them in their decision-making process to ensure site contamination would not adversely impact any downgradient water supply wells. Another challenge was that the site property was used as a residence that obtained its potable water from the original site monitoring well. The residents were supplied with water after it was determined that their supply well contained TCE levels greater than the MCL.
The nature and extent of the site contamination was determined by the existing network of monitoring wells plus the addition of eight wells to supplement the existing network and to determine off-site impacts. Soil samples were collected from borings advanced using sonic drilling equipment. The RI concluded that the TCE plume was delineated on all sides; Fate and transport processes, including advection, diffusion, dispersion, adsorption, and volatilization, appear to be reducing and attenuating contaminant mass along the direction of groundwater flow and that it appears that reductive dechlorination is taking place within the aquifer; and, the total site-related risks were considered acceptable. The RI was completed in 18 months following notice to proceed.