SWMU 54 – Fluorescent Tube Well No. 3

Proposed Remedial Measure

The proposed remedy in the RFI (2016) for SWMU 54 Fluorescent Tube Well-3 (FTW-3) was a removal action for residential exceedances of lead in surface soil at FTW-3. The removal action would include excavation and off-site disposal for soils. Excavation and removal of soil off-site to an appropriate landfill or treatment facility was completed as an Interim Corrective Measure (ICM) summarized below.

The RFI (2016) and final Corrective Measures Implementation Completion Report (CMICR 2020) indicated that site-specific contaminants of concern (COCs) for groundwater were below the TMDLs for the COCs. Therefore, site-specific groundwater will be considered clean and included as a No Further Action (NFA) remedy.

Justification

Fluorescent Tube Wells (SWMU 54) were used during SFAAP operations to dispose of fluorescent light tubes and incandescent light bulbs. During the RCRA Facility Investigation (RFI) (Louis Berger 2016), in situ XRF readings, surface soil samples, subsurface soil samples, and groundwater samples were collected and analyzed for the chemicals of interest at SWMU 54. RCRA metals were tested in surface and subsurface soils with no TMCL exceedances except for lead. Lead exceeded the TMCL for residential use but did not exceed the limit for non-residential TMCLs. Lead is considered the contaminant of concern (COC) for the site surface soils.

Based on the RFI, there was no evident impacts to groundwater at SWMU 54 FTW-3. Three monitoring wells were installed l and sampled, with lead detected below the residential TMCLs for the sites. No site-specific COCs were identified in groundwater.

Additional groundwater evaluation for site-wide contamination will occur when the OU-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 54. Only surface soils were impacted by the operation of the site. Based on the limited distribution lead and the poor transport characteristics of these contaminants, contamination at SWMU 54 is contained within surface soils and is unlikely to migrate, to any appreciable distance, into subsurface soils and groundwater. However, with only one groundwater sample to characterize the potential of contamination at this site, groundwater will be further evaluated during the OU-4 groundwater site-wide investigation.

The Army conducted a streamlined health risk evaluation by comparing RFI data to the approved TMCLs for the site. KDHE believes that proper employment of the KDHE (2021) 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 Johnson County Rural Comprehensive Plan Resolution No. 079-98. Conceptual Land Use Plan, Sunflower Army Ammunition Plant. July 23, 1998 the area encompassing SWMU 54 is proposed to be used as industrial land. Based on this land-use, the potential current and future receptors include:

• Current: Construction and excavation workers.

• Future: Construction workers, manufacturing facility employees and visitors.

The RFI identified lead as a COC at SWMU 54 FTW-3 based on exceedances of the residential soil TMCL, therefore, the exposure pathway for soil was considered during the assessment. Soil: Evaluated exposure pathways include incidental ingestion, inhalation of airborne particulates (dusts), inhalation of chemicals volatilizing from soil (volatile compounds only), and dermal contact (organic compounds only). Based on comparison of the RFI results to TMCLs, which identified exceedances and therefore pose a potentially unacceptable health risk for residential but below the non-residential, the following corrective action objectives (CAOs) were established for surface soil SWMU 54:

• Excavation and disposal of lead impacted soil

• Removal of water/sediments and the Abandonment of FTW-3

Lead was not identified in the one groundwater sample collected at the site. Additional evaluation of groundwater in the area will occur when work on OU-4 is done.

KDHE Site Documents