St. Louis Airport Site Vicinity Properties

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The St. Louis Airport Site Vicinity Properties are located in the cities of Hazelwood and Berkeley, Missouri. These properties (totaling approximately 80) include Coldwater Creek and its vicinity properties to the west; adjacent ball fields to the north and east; Norfolk and Western Railroad properties adjacent to Coldwater Creek; Banshee Road to the south; ditches to the north and south; and St. Louis Airport Authority property to the south. Also included are the transportation routes (haul roads) at the following locations: Latty Avenue, McDonnell Boulevard, Pershall Road, Hazelwood Avenue, Eva Avenue, Frost Avenue, and vicinity properties.

FACILITY MISSION

Low­level radioactive contamination at the St. Louis Airport Site Vicinity Properties [estimated at 149,000 cubic meters (195,000 cubic yards)] consists primarily of soils and sediment contaminated with residues from the processing of high-grade uranium ore. The contamination at the vicinity properties is linked to both the St. Louis Airport Site and the Latty Avenue Properties. The Manhattan Engineer District acquired the St. Louis Airport Site in 1946 and used it to store uranium-bearing residues from the St. Louis Downtown Site from 1946 to 1966, when Continental Mining and Milling Company of Chicago purchased the waste, removed it from the storage site near the airport, and placed it in storage at Latty Avenue under Atomic Energy Commission license. Over time, residues migrated from other sites or were deposited when waste was hauled along transportation routes, and the soils and sediments at the vicinity properties became contaminated. Commercial enterprises, individuals, or local governments own the vicinity properties.

FUTURE USE

The final land-use range will depend on the Record of Decision that will document the remedial action alternative selected for implementation. This estimate assumes that land use of the vicinity properties will be the same as the current uses, which range from recreational to industrial/commercial. The Record of Decision will involve input from the Environmental Protection Agency, state and local agencies, and stakeholders.

ENVIRONMENTAL RESTORATION

Environmental restoration of the St. Louis Airport site Vicinity Properties is expected to involve disposition of approximately 149,000 cubic meters (195,000 cubic yards) of soil. Cleanup will be conducted under the Comprehensive Environmental Response, Compensation, and Liability Act protocol for remediation of low-level radioactive contamination at FUSRAP sites and the Atomic Energy Act of 1954, as amended. Because the site is on the National Priorities List, a Federal Facilities Agreement negotiated between the Department and the Environmental Protection Agency incorporates procedural and documentation requirements of the Comprehensive Environmental Response, Compensation, and Liability Act and establishes the roles of each agency during site remediation. As required by the Comprehensive Environmental Response, Compensation, and Liability Act, development of remediation goals for the site will incorporate applicable or relevant and appropriate requirements of federal and state laws.

Key regulators are Environmental Protection Agency Region VII, the St. Louis Airport Authority, the City of St. Louis, the Missouri Department of Natural Resources, and local governments as appropriate. Other regulatory drivers include the Clean Air Act, the Safe Drinking Water Act, and the National Pollutant Discharge Elimination System.

The schedule for final cleanup depends on the issuance of a Record of Decision and funding. Waste management strategies will be developed to address pollution control; waste treatment, storage, disposal, and transportation; interface requirements; and implementation of new technology.

ASSESSMENT

Contaminants at the St. Louis Airport Site Vicinity Properties include uranium­238, radium­226, thorium­230, and thorium­232; the primary contaminant is thorium­230. Based on limited chemical characterization at the ball field area, no Resource Conservation and Recovery Act-hazardous characteristic waste is present. Chemical analysis of Coldwater Creek samples revealed the presence of four metals at concentrations exceeding both sample detection limits and background levels. Chemical characterization at the other vicinity properties was deemed unnecessary because of the low levels of chemical contamination found during characterization at the St. Louis Airport Site. The Department's present objective at the St. Louis Airport Site Vicinity Properties is to eliminate or reduce the potential for exposure to radioactive and chemical contaminants.

The potential for contaminant transport results from the movement of contaminated soils via surface runoff, ground water, surface water and sediments, and air. In addition, road and underground utility improvements may have caused migration of contamination onto adjacent land. Contamination could spread from the areas along the creek bank that contain elevated radioactivity if sediment were transported by high flow of the creek or otherwise disturbed; however, installation of a gabion wall at the eastern bank of the creek has stabilized creek flow and greatly reduced erosion. Release of contaminants into the atmosphere appears unlikely because there are currently no operations in the area that would cause contaminants to become airborne; most areas of outdoor surface contamination are vegetated, paved, or covered with gravel.

Potential exposure pathways are ingestion and inhalation. Because ground water is not used as a potable water source in the St. Louis area, the potential for human exposure via this pathway is minimal. Land use near the St. Louis Airport Site Vicinity Properties is transportation-related and Industrial/Commercial; existing sources of contamination do not present a risk to workers or the public under current land-use conditions.

Radiological characterization at the St. Louis Airport Site Vicinity Properties began in 1982 and continues in various portions of the site. Radiological surveys and characterization conducted at the St. Louis Airport Site Vicinity Properties generally involved establishing a reproducible grid system; clearing the area to be surveyed; performing gamma radiation walkover scans and near­surface gamma radiation measurements; taking direct alpha and beta-gamma measurements on structure surfaces; collecting and analyzing samples for radiological and chemical constituents; and collecting and analyzing geologic and hydrogeologic data to characterize subsurface transport.

Thorium-230 was identified as the primary radioactive contaminant at all St. Louis Airport Site Vicinity Properties characterized. In general, contamination was confined to the boundaries of properties adjacent to the haul roads and was detected to a maximum depth of 0.6 meter (2 feet). Soil sampling along the haul roads revealed radioactive contamination in areas under Latty Avenue, McDonnell Boulevard, and Pershall Road; along both sides of Hazelwood Avenue, Pershall Road, and Eva Avenue; and primarily on the northern side of Frost Avenue. Radioactive contamination (primarily thorium­230) exceeding guidelines was detected on portions of all the Norfolk and Western Railroad properties, except the property adjacent to Hanley Road and Hazelwood Avenue, north of Latty Avenue. Depths of contamination ranged from 0 to 2.1 meters (0 to 7 feet).

The City of St. Louis leases the ball field area north of St. Louis Airport Site to the City of Berkeley. Analytical results for soil on this property revealed areas with elevated concentrations of radium­226 in surface samples and thorium­230 in both surface and subsurface samples. The radioactive contamination averages 0.3 meter (1 foot) in depth over the first 45.7 to 61 meters (150 to 200 feet) along the northern border of McDonnell Boulevard. The infield areas of the ball fields showed no contamination.

Elevated concentrations of thorium­230 in surface soil samples were detected in several areas on the St. Louis Airport Authority property to the south of St. Louis Airport Site. In general, the maximum depth of contamination was 0.6 meter (2 feet); the extent of contamination encompassed the length of the property's border with St. Louis Airport Site. Two small areas with elevated concentrations of thorium­230 in soil to a depth of 0.3 meter (1 foot) were identified at Banshee Road, which forms the southern boundary of St. Louis Airport Site. Analytical results for soil at the ditches to the north and south of St. Louis Airport Site revealed areas with elevated concentrations of radium­226 and thorium­230 (the major contaminant) in surface and subsurface samples. Essentially all the ditch area north and south of St. Louis Airport site is contaminated; the depth of contamination ranges from 0 to 4.3 meters (0 to 14 feet).

Surface soil and sediment samples from Coldwater Creek and vicinity properties were collected in 1986 from the sides and center of the creek at 30.5­meter (100­foot) intervals beginning at St. Louis Airport Site and continuing downstream to Hazelwood Interim Storage Site. The data from these analyses indicated spotty contamination over the entire distance. Analytical results for sediment revealed areas with elevated concentrations of thorium­230, which is the primary contaminant in Coldwater Creek. Results from the 1987 characterization indicated areas with elevated radium­226 and thorium­230 concentrations. During additional characterization in 1989, soil samples were collected from the banks on both sides of the creek north of Pershall Road. Radionuclide concentrations were above guidelines in 64 of 175 samples. A 1989 Corps of Engineers survey similarly revealed areas with thorium­230 concentrations exceeding guidelines in surface samples. Areas of contamination were most numerous between St. Louis Airport Site and Pershall Road, adjacent to St. Louis Airport Site and Hazelwood Interim Storage Site. A correlation has been observed between the creek's configuration and the areas of contamination: above-guideline concentrations of thorium­230 appear to be localized along the inner banks of the creek at the bends, indicating settling of contaminated sediment. Six of the Coldwater Creek vicinity properties have thorium­230 contamination in excess of guidelines, primarily in the first foot of soil.

Assessments of contamination are documented as required by the regulatory process. In addition to the Remedial Investigation/Feasibility Study­Environmental Impact Statement and Record of Decision for the St. Louis Sites, environmental documentation for St. Louis Airport Site Vicinity Properties includes a site designation report, a Notice of Intent, planning documents (work plan, field sampling and analysis plan, quality assurance plan, community relations plan), and characterization reports.

REMEDIAL ACTION

This report anticipates a phased approach to remedial action, beginning with a Record of Decision that specifically identifies near­term actions and outlines commitments for the future. During an interim removal action at the St. Louis Airport Site Vicinity Properties in 1995, approximately 1,070 cubic meters (1,400 cubic yards) of waste was removed from six properties and shipped to Envirocare of Utah for disposal. Future interim actions are planned within the next two to three years, to the extent that funding permits. An Engineering Evaluation/Cost Analysis report and a categorical exclusion report have documented environmental impacts of interim removal actions that have been conducted to address contamination on portions of the St. Louis Airport Site Vicinity Properties before finalization of the Record of Decision.

This report anticipates that a design basis document will be developed to govern the requirements for the scope of work for final cleanup of the site. Site­specific remedial action is expected to include civil survey, material testing, excavation, and backfill, as well as miscellaneous services such as water treatment, fence repair, maintenance, trailer setup, mobilization and demobilization of equipment, handling of contaminated material, janitorial services, and health physics and analytical laboratory services.

The scenario used for the Baseline Environmental Management Report cost estimate for the St. Louis Sites assumes excavation of accessible soils from St. Louis Downtown Site, vicinity properties in the downtown and airport areas, the Latty Avenue Properties, and sediments at Coldwater Creek, as well as consolidation and capping at St. Louis Airport Site. The cost estimate assumes a total waste volume of 149,000 cubic meters (195,000 cubic yards) of low-level waste at the St. Louis Airport Site Vicinity Properties.

FUNDING ESTIMATE

The following table presents estimated funding information for the St. Louis Airport Site Vicinity Properties.