Cleanup Activities
There are no current cleanup activities.
Cleanup/Treatment Implemented:
N
Cleanup/Treatement Categories:
Addl Cleanup/Treatment info:
The scope of work for the additional VI assessment consisted of the installation of six permanent sub-slab active soil gas sampling points (PSS-6 through PSS-11) to delineate the extent of soil gas impact identified at SS-1. The sub-slab soil gas samples were analyzed for VOCs by TO-15 Volatile Organics in Air Method.
The sub-slab soil gas samples collected at the subject property indicate that target analytes are present beneath the building at concentrations exceeding the VISLs for Residential Receptors.
Based on the TDEC VI Guidance, the results of the VI risk evaluation indicate that risk thresholds for a Residential scenario are exceeded and represent an unacceptable exposure risk to future building occupants. At a minimum, passive VI mitigation will be required for this property under the TDEC Voluntary Cleanup Oversight and Assistance Program (VOAP).
Additionally, it is noted that the proposed future use of the subject building is as a fire hall. Although workers would be present at the fire hall overnight, the default residential exposure scenario utilized in the EPA VISL Calculator (24 hours/day, 350 days/year, 26 years) is unlikely based on the proposed future use. As such, commercial worker exposure factors in the EPA VISL Calculator were adjusted to reflect an exposure scenario between that of a resident and typical commercial worker (8 hours/day, 250 days/year, 25 years). Based on this modified commercial exposure scenario, the calculated cumulative carcinogenic risk value for the site was still more than twice the mitigation threshold presented in the TDEC VI Guidance.
Based on the results of the soil, groundwater, and soil gas sampling, the source area appears to be localized beneath the main on-site building slab. Source removal is not practical given the reuse plans for the Subject Property, and mitigation that addresses potentially complete exposure pathways is appropriate. It is PM's professional opinion that vapor mitigation should be incorporated into future redevelopment plans in accordance with the TDEC VI Guidance.
Asbestos Containing Materials
Due to the combination of issues requiring cleanup action, the recommended cleanup option is Alternative #2: Abatement and Disposal. Alternative #1: "No Action" does not address the site risks. Without cleanup or removal of the asbestos the subject property will always contain asbestos containing materials inhibiting redevelopment of the site.
The long-term solution of removal and proper disposal of ACM from the subject property is the only alternative that allows the property owner to move forward with the proposed redevelopment of the property.
Vapor Intrusion
Due to the combination of issues requiring cleanup action, the recommended cleanup option is Alternative #3: Passive Vapor Intrusion Mitigation System. Alternative #1: "No Action" does not address the site risks. Without mitigation of sub-slab vapor, the subject property will pose as a vapor intrusion concern for future occupants which will inhibit redevelopment of the site. Alternative #2: Active Sub-Slab Depressurization System would effectively mitigate sub-slab vapor, but continuing obligations, operation, and maintenance of an active system will result in significant long-term costs and presents long-term effectiveness concerns related to system failure.
The long-term solution of installing a passive VIMS on the subject property is the best alternative that allows the property owner to move forward with the cleanup and redevelopment of the property, as proposed.
Address of Data Source:
Total ACRES Cleaned Up: 2.41
Number of Cleanup Jobs Leveraged:
EPA Cleanup Funding:
Leveraged Funding:
Cost Share Funding:
Total Funding:
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