SWMU 59 - Laundry Facility

Justification

The former Sunflower Army Ammunition Plant (SFAAP) is located near DeSoto, Kansas, in the northwest corner of Johnson County. It is approximately 30 miles southwest of Kansas City, Kansas, and 16 miles east of Lawrence, Kansas. The plant consisted of production facilities, administrative and storage facilities, powerhouses, landfills, lagoons, ditches, burning grounds, sumps, projectile ranges, and waste treatment facilities. The site is composed of 70 Solid Waste Management Units (SWMUs) where a release of hazardous waste was identified and 27 Areas of Concern (AOCs) where hazardous waste or constituents have been identified but are not linked to a specific solid waste management practice.

SWMU 59, Laundry Facility, is in the north-central portion of the former SFAAP. The site encompasses approximately 0.7 acres and consists of the former laundry facility (building 4562), former 2,950-gallon (gal) diesel fuel oil above ground storage tank (AST), and a newer 1,000-gal fuel oil AST, which was never used. The building was a one-story, wood frame, “L-shaped” structure with a concrete foundation. All sumps and drains were connected to the storm sewer that discharges approximately 1,200 feet (ft.) southeast of the site. SWMU 59 has a gentle slope to the east-southeast and is bordered by perimeter fencing on the north and west. The Laundry Facility (SWMU 59) was primarily used to remove process waste and propellant contamination from workers’ clothing and dry-cleaning military dress clothing. The facility also performed flame retardant application in the north-south wing. The 2,950-gal AST was used for storing fuel for the boiler and the 1,000-gal AST was installed on a concert pad but never used.

During the (Resource Conservation and Recovery Act ) RCRA Facility Investigation (RFI) (Louis Berger and BMcD, 2018), surface, subsurface, and groundwater was sampled, and lead, arsenic, and chromium were determined to be Contaminants of Primary Concern (COPCs) at the site. Thirty-eight in situ XRF readings, 16 surface soil samples, 7 surface soil drainage samples, 23 subsurface soil samples, and 2 groundwater sample were collected and analyzed for the chemicals of interest at SWMU 59. All surface and surface drainage soil samples were analyzed for metals, Total Petroleum Hydrocarbons (TPH)-diesel range organics (DRO), TPH-motor oil, explosives, guanidine nitrate (GN), nitrocellulose (NC), nitroguanidine (NQ), polychlorinated biphenols (PCBs),Semi-volatile organic compounds (SVOCs), volatile organic compounds (VOCs), nitrate/nitrite, ammonia, and pesticides with no TMCL exceedances except for Lead and Arsenic. Lead and arsenic are considered the contaminants of concern (COCs). Subsurface soils were analyzed for metals, TPH, explosives, PCBs, SVOCs, VOCs, nitrate/nitrite, ammonia, total solids, and pesticides and had no Target Media Cleanup Level (TMCL) exceedances. Groundwater samples were analyzed for VOCs and had no TMCL exceedances. Two wells were installed. The completed wells yielded minimal groundwater that was only sufficient to collect aliquots for VOCs. No VOCs were detected in the samples. Additional groundwater evaluation will occur when the Groundwater Operating Unit (GWOU) 4 sitewide assessment occurs. Soil screening and laboratory analytical data delineated the lateral and vertical extent of impacts of the COCs in environmental media at SWMU 59. Only surface soils were impacted by the operation of the site.

In 2019, Interim Corrective Measures (ICMs) were implemented and completed (Zapata, Burns & McDonnell, and Envirocon, 2019). Contaminated soils were excavated to a depth of 1.0 feet below ground surface (bgs) to address the lead and arsenic TMCL exceedances. The concrete slab associated with building 4562 was removed and transported to a central concrete stockpile area. Surface soils were analyzed for metals (including antimony), explosives, NC, GN, NG, NQ, and low, medium, and high range TPHs. Nine composite samples were collected, and all concentrations tested below the associated TMCL. The excavated area was back filled following the completion of removal activities.  

The Army conducted a streamlined health risk evaluation by comparing RFI data to the approved Target Medial Cleanup Levels for the site. KDHE believes that proper employment of the KDHE (2015) RSK Manual values result in risk-based remediation that is consistent with federally promulgated standards, including the Safe Drinking Water Act, 42 U.S.C. §300f – 300j-26, and is protective of human health as required by Resource Conservation and Recovery Act, 42 U.S.C. §6901 et seq., including the Hazardous and Solid Waste Amendments (HSWA) and 40 CFR Part 264.101. KDHE Tier 2 risk-based cleanup goals represent concentrations at which the contaminants pose an acceptable human health risk to receptors, including sensitive groups (e.g., children or the elderly), over a lifetime.

Cleanup goals were developed for two general categories of receptors, residents and non-residents, according to the appropriate land-use designation, exposure frequency, and exposure duration. According to the Conceptual Land Use Plan, SWMU 59 falls within the area designated as business and manufacturing (Johnson County, 1998).

The KDHE has determined that excavation and disposal addresses detected surface soil contamination. This alternative offers an effective, implementable, and timely method to control risks associated with contamination in the surface soil that is also cost-effective and would eliminate future liability for the detected lead contamination. The interim corrective measures were appropriate for the site to be protective of human health and the environment, therefore No Further Action (NFA) will be evaluated for this SWMU.  KDHE has also determined the groundwater sampling performed to date indicates the site-specific groundwater is considered clean and NFA is warranted for groundwater. The decision is based upon KDHE’s review of all available historical documentation.