No previous Phase I Environmental Site Assessment (ESA) or subsurface investigation has been conducted for the site. The following potential areas of concern (PAOCs) that may adversely impact the site subsurface quality (soil and or groundwater) were identified, which may lead to potentially significant site contamination issues:
Former Landfills. Three landfills were formerly operated at the site. Landfill 1 is reported to have contained construction waste and cellophane wastes in the late 1950s. Landfill 2 contained cellophane waste generated at the site and was active during the 1960s. No information regarding Landfill 3, was available. This is the landfill in which leachate had impacted shallow groundwater. Landfill 3 has been closed and capped. All three landfills are reported to be managed by DuPont. DuPont is reported to have retained all liability for these landfills. Closure documentation for the former landfills was not available for Ramboll Environ’s review.
Spills and Releases to Soil and Surface Water. Review of the EDR report and the KDHE Bureau of Environmental Remediation (BER) Spills database indicates that there have been approximately seven spills/emergency responses (ERNS) /hazardous material releases (HMRIS) to soil, and 14 spills/ERNS/HMRIS to surface water since 1990 through 2015. Three of the spills (50,000 pounds of carbon disulphide spill to surface water in 2011, a 5,000 gallon sodium hydroxide spill to surface water in 2015, and a sulfuric acid spill to soil in 2014) are listed with an open status, which have been referred for further evaluation or remediation. The remaining spills/ERNS/HMRIS incidents (i.e., THF, carbon disulphide, sulfuric acid, gypsum solution, toluene, sodium hydroxide) have all been closed. No subsurface investigations or sampling was listed for these incidents. Facility personnel, indicated that all of the spills/ERNS/HMRIS have been addressed, contaminated soil has been removed and disposed off-site or neutralized on site. Copies of the corrective actions were not available for Ramboll Environ’s review.
Potential Impacts from Historical and Current Agricultural Use. The main plant area site was farmland before its initial development in the mid-1950s. Portions of the eastern and southern parcels within the main plant area are also currently used for land application of the site treated process wastewater and for application of gypsum. The vacant parcel north of the Kansas River is still used as agricultural land. Therefore, there is a possibility that residual pesticides are present in the shallow soils at the site. No records of pesticide usage at the site area were available for review. Facility personnel reported no knowledge of past subsurface testing for any pesticides. Although this matter is not considered a REC, the potential presence of these compounds in the site subsurface cannot be ruled out. Ramboll Environ notes that this matter is unlikely to result in regulatory scrutiny, assuming no changes to site use. Further, KDHE has approved the land application plan for the site.
Potential Impacts from Underground Piping and Trenches. Review of EDR report and according to facility personnel, various drainage piping at the main plant area have collapsed and released wastewater and/or product to the subsurface. Review of the 2013 Phase I report indicated that the underground sewer lines were replaced between 2008 and 2013. The underground piping system consist of two separate sewer systems, one each for acid-based wastewater and alkaline-based wastewater. According to facility personnel, the clay piping was replaced with PVC. Upgrading history of the underground piping system was not available for Ramboll Environ’s review. During the site visit, Ramboll Environ observed various soil piles at the main plant area. According to facility personnel, the soil piles are from where underground piping has collapsed and been replaced or remediation due to a spill has occurred. The soil was awaiting analysis for off-site disposal or reuse on-site. Additionally, review of the Core Drilling and Testing report conducted by GeoSource in 2012 (the “2012 Core Drilling and Testing report”), indicates that in 2012 a trench failed in the production area. Sampling of the subsurface soils only included moisture and pH.