Objective 1: Meet TNRCC Requirements for Site Closure

Attainment of Risk Reduction Standard Number 1: Closure/Remediation to Background

Attainment of Risk Reduction Standard No. 1 (cont.)

Attainment of cleanup levels shall be demonstrated by collection and analysis of samples from the media of concern (30 TAC 335.554(e)).

Surface soil and shallow groundwater samples were collected at the site and analyzed for contaminants of potential concern, including metals, VOCs, and SVOC’s.

Yes. See above.

RRS1 site closure is recommended.

Objective 2: Meet Requirements of 3008(h) Order for RFI

RFI Workplan Requirements

Field Sampling (Detailed listing of methods and procedures are provided in project plans which are incorporated by reference).

Conduct field sampling in accordance with procedures defined in the project work plan, SAP, QAPP, and HSP.

All sampling was conducted in accordance with the procedures described in the project plans.

Yes.

NA

Facility Investigation

Characterization of Environmental Setting - Hydrogeology (B.3.A.1)

Evaluate hydrogeologic conditions at the site.

Perched shallow groundwater was encountered in two soil borings during drilling at the site.

Groundwater of the Trinity Aquifer is being addressed through the Groundwater Investigation.

NA

NA

Characterization of Environmental Setting- Soils (B.3.A.2)

Characterize soils in accordance with USCS soil classification system (B.3.A.2(a)).

Soil types at the site are based on the SCS Bexar County Soil Survey (USDA, 1991) and are described in Section 1.2.1.

Yes.

Yes

Characterization of Environmental Setting- Soils (B.3.A.2) (cont.)

Determine soil pH (B.3.A.2(e)).

The pH of each of the soil types evaluated as part of the background metals concentration study was determined through laboratory analysis. According to those analyses, a pH of 7.90, 7.87, 8.08 and 7.97 were found in Trinity-Frio, Krum Complex, Tarrant (undulating) and Lewisville, respectively.

Yes.

NA

Determine moisture content (B.3.A.2(g)).

The moisture content of each sample was analyzed. Moisture content values are provided in the laboratory packages.

Yes.

NA

Characterization of Environmental Setting – Surface Water and Sediment (B.3.A.3)

Characterize marshes, creeks, wetland areas, or ditches at the site.

No marshes, creeks, wetland areas, or ditches are present at the site. Direction of runoff flow has been evaluated in Section 1.2.3.

NA

MA

Source Characterization (B.3.B)

Identify the source area (B.3.B.1).

A description of the source area is provided in Section 1.1.2.2.

Sampling at the site was biased toward areas most suspected of contamination. No contamination was found.

NA

Identify the location of the unit/disposal area (B.3.B.2(a)).

The boundaries marked on aerial photo by CSSA’s environmental coordinator were digitized.

Yes. Although the accuracy of the boundary survey of the site is estimated to have an approximate error of 25 feet, this accuracy is sufficient for closure under RRS1.

NA

Identify the type of unit/disposal area (B.3.B.2(b)).

The type of unit/disposal area was identified a records review. It was used for burning powder and incendiary materials.

Yes. A geophysical survey and surface soil sampling were performed. No evidence of buried waste was found, and surface soil samples indicated no waste residue.

NA

Source Characterization (B.3.B) (cont.)

Identify design features (B.3.B.2(c)).

Information regarding design features was obtained during the Environmental Assessment (ES, 1992) and through visual observation during the field investigation.

Yes.

NA

Identification of past and present operating practices, period of operation, age of unit/disposal area, and method used to close the unit/disposal area (B.3.B.2(d), (e), (f), and (h)).

All known information regarding these items is provided in Section 1.1. This information is from the Environmental Assessment, records review, interviews, and visual observations.

To the extent possible with data available.

NA

Determine general physical conditions of the site (B.3.B.2(g))

The general physical condition of the site was determined during the field investigation. This information is presented in Section 1.1.2.1.

Yes.

NA

Identify waste characteristics, including type of waste placed in the unit, physical and chemical characteristics of the wastes, and migration and dispersal characteristics of the waste (B.3.B.3).

Records regarding historic waste disposal practices at CSSA are very limited. All known information, derived from the Environmental Assessment (if appropriate for your site), records review, interviews, and visual observations at the site is provided in Section 1.1.2.2.

Yes.

NA

Contamination Characterization- Soil (B.3.C.2)

Determine vertical and horizontal extent of contamination (B.3.C.2(a)).

Shallow groundwater was encountered during the drilling of two soil borings. The test results of these samples indicate no contaminants above RLs.

Soil samples collected from the soil borings and analyzed for contaminates of concern indicate that the vertical and horizontal extent of contamination has been determined.

Yes.

NA

Contamination Characterization- Soil (B.3.C.2.) (cont.)

Describe contaminant and soil properties with the contaminant source area, including contaminant solubility, speciation, adsorption, leachability, exchange capacity, biodegradability, hydrolysis, photolysis, oxidation, and other factors that might affect contaminant migration and transformation (B.3.C.2(b)).

No contaminant levels were above the RLs.

Yes.

NA

Describe soil properties (B.3.C.2(c)).

See “Characterization of Environmental Setting – Soils” above.

Yes.

NA

Identify the direction of contaminant movement (B.3.C.2(d)).

No actions taken based on low contaminant levels detected.

NA

NA

Extrapolate future contaminant movement (B.3.C.2(e)).

No actions taken based on low contaminant levels detected.

NA

NA

Implement a soil boring investigation to determine the extent of soil contamination. Soil gas monitoring will be performed during drilling of all borings. Laboratory analysis of borings for contaminants of potential concern will be performed on soils at depths where either visual contamination is evident, or soil gas concentrations indicate contamination. All boreholes shall be properly abandoned.

A phased approach is being taken for the investigation SWMU B-1. The first phase included a geophysical survey to determine if a trench may be located at the site. Surface and subsurface soil samples were collected to determine if there is surface and subsurface contamination. A PID was used to monitor soil gas concentrations during drilling. All boreholes were properly abandoned.

Yes.

NA

Prepare a map of all areas included in the investigation (B.3.C.2(i)).

Figures included in this report show all areas included in the investigation.

Yes.

NA

All reporting limits should be below regulatory criteria.

RLs were approved by TNRCC on October 5, 1999. RLs are considered RRS1 standards for all analytes except metals.

Yes.

NA

Perform all analyses in accordance with the AFCEE QAPP.

All analyses were performed in accordance with the AFCEE QAPP and approved variances.

Yes.

NA

Contamination Characterization- Soil (B.3.C.2.) (cont.)

Perform all analyses in accordance with the AFCEE QAPP (cont.).

All data flagged with “U,” “F,” “M,” and “J” are considered usable for site characterization purposes.

Yes.

“M” flagged data are also considered usable. The matrix interference is minimal and does not significantly affect the sample results.

NA

Contaminant Characterization – Sediment and Surface Water (B.3.C.3)

Conduct a surface water and sediment investigation to characterize contamination resulting from releases at the facility.

SWMU B-1 is located adjacent to an unnamed intermittent stream that flows south and joins Salado Creek approximately 2,000 feet south of the site. In the vicinity of CSSA, Salado Creek only contains water during and shortly after heavy precipitation. Therefore, surface water was not sampled as part of the SWMU B-1 investigation. Sampling of sediments in association with the SWMU B-1 investigation is not warranted due to the very limited amount of contamination detected at SWMU B-1.

Yes.

NA

Potential Receptors (B.3.D).

Collect the information necessary to describe the human populations and environmental systems that are susceptible to contaminant exposure from the Facility.

Information regarding receptors is provided in the Risk Assessment Technical Approach Document (Volume 1-6). In addition, the Well Research Report identifies private groundwater users within 0.25-mile and public water suppliers within 0.5-mile of CSSA.

Yes.

NA