This report presents the technical findings of Phase I of Argonne?s studies. The Phase I field investigation was initiated on October 18, 2010. The work was conducted in accord with (1) the final site-specific Phase I Work Plan for Montgomery City (Argonne 2010
approved by the MDNR [2010])
(2) applicable Missouri regulations
and (3) the standard operating procedures, quality assurance/quality control (QA/QC) measures, and general health and safety policies outlined in the Master Work Plan (Argonne 2002) for operations in Kansas, which was reviewed by the MDNR and accepted for current use. A draft master plan specific to work in Missouri and a set of draft standard operating procedures are in review with the MDNR. The site-specific Work Plan for Montgomery City (Argonne 2010) (1) summarizes the pre-existing knowledge base for the Montgomery City investigation site compiled by Argonne and (2) describes the site-specific technical objectives and the intended scope of work developed for the first phase of the investigation. Three primary technical objectives were identified for the Phase I studies, as follows: 1. Update the presently identified inventory and status of private and public drinking water wells in the immediate vicinity of the former CCC/USDA grain storage facility, and sample the identified wells for volatile organic compounds (VOCs) and geochemical analyses. In conjunction with this effort, determine the present sources(s) of drinking water for all residents in an approximate 0.5-mi radius of the former CCC/USDA facility. 2. Investigate for possible evidence of a soil source of carbon tetrachloride contamination in the unconsolidated sediments beneath the former CCC/USDA facility that might affect the underlying bedrock aquifer units. 3. Obtain preliminary information on the site-specific lithologic and hydrologic characteristics of the unconsolidated sediments overlying bedrock at the former CCC/USDA grain storage location. Section 2 of this report describes the investigative methods used in the 2010-2011 studies and provides a chronological summary of the field events conducted. Section 3 presents a summary of the resulting field and laboratory data. These data, together with information presented in the site-specific Work Plan (Argonne 2010), are interpreted and integrated in Section 4 to (1) develop a preliminary conceptual model of the hydrogeologic framework affecting groundwater and potential contaminant migration in the vicinity of the former CCC/USDA facility and (2) serve as a basis for the initial consideration of contaminant levels and potential exposure pathways that might be of concern in the evaluation of risks to human health, public welfare, and the environment. The working conclusions drawn from the 2010-2011 studies are presented, along with recommendations, in Section 5.