Objective 1:  Meet TNRCC Requirements for Site Closure

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

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

Remove all hazardous and nonhazardous waste and waste residues and contaminated design and operating system components such as liners, leachate collection systems, and dikes from the unit or area of the unauthorized discharge. For remediation of media that have become contaminated by releases from a waste management unit or by other unauthorized discharge of hazardous or nonhazardous waste, the contaminated media must be removed or decontaminated to cleanup levels specified in this section (30 TAC 335.554(b) and (c)).

UXO sweep and removal has been conducted over the entire site.   Soil excavation and sifting activities have been completed in the northern portion of the site.  Sampling of surface soil, subsurface soil, sediment, surface water, and groundwater was conducted.

No. Additional UXO removal activities are required along with remediation or removal of the metals-contaminated soils (both in-situ and in stockpiles).

Remediation or disposal of contaminated soil using method identified during the upcoming Soil Pile Disposition Assessment Study is recommended.  Prior to completing this remediation, additional surface soil sampling should be conducted to determine the limits of contaminated in-situ soils.  Removal of metal scrap and possible UXO within the in-situ soils should be conducted prior to remediation.  Verification sampling should be conducted at the conclusion of the remediation or removal.

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

Determine compliance with RRS1 closure requirements by comparing to background as represented by results of analyses of samples taken from media that are unaffected by waste management or industrial activities. If the practical quantitation limit (PQL) is greater than background, then the PQL rather than background shall be used as the cleanup level provided that the person satisfactorily demonstrates to the executive director that lower levels of quantitation of a contaminant are not possible (30 TAC 335.554(d)). 

Contaminant concentrations were compared to draft revised background levels (Parsons ES, May 2001) or PQLs.

No.  Elevated levels of barium, cadmium, copper, lead and mercury were identified in the soils at the site.  

The soils at SWMU B-20/21 will be included in treatability study activities.  Additionally, soil samples should be collected to verify the current extent of contaminated surface soils.

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

Soil samples were collected from the stockpiles of sifted soils generated during the UXO removal activities.  Contaminants of concern were VOCs, SVOCs, explosives, and metals.

No.  Contamination above background levels was detected.

Additional soil sampling and remediation of contaminated soils and UXO is required.

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

B.2.  Task II: 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

B.3.  Task III:  Facility Investigation

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

Evaluate hydrogeologic conditions at the site. 

Not included in this phase of the RFI at SWMU B20/21.  Perched groundwater was not encountered during drilling at the site, except at one boring where a small amount was encountered in 1995.  No analytes exceeded MCLs in the sample.

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.

NA

Identify soil profile, including ASTM classification of soils; directional relative permeability; bulk density; particle size distribution; infiltration (field test); storage capacity; mineral content; and soil conductivity (B.3.A.2(b), (c), (d), (f), (h), (i), (j), (k))

None.

No.

Information regarding soil characteristics necessary for treatability studies will be assessed as part of the soil pile disposition assessment.

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

The pH of each of the soil types was evaluated as part of the background metals concentration study.  Three soil types were identified at the site.  pH values are as follows:  Krum, 7.87; Crawford and Bexar, 7.89; and Brackett-Tarrant, 8.11.

Yes.

NA

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

The moisture content of each sample was determined through laboratory analysis.  Results are included in the analytical 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.

Two intermittent streams are present at the site.  No marshes or wetland areas are present.  Direction of runoff flow has been evaluated in Section 1.2.3.  Samples of sediment and surface water were collected in 1995.  Results are described in Section 1.3.

Yes.

NA

Source Characterization (B.3.B)

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

A description of the source area is provided in Sections 1.1 and 1.2.

Shallow soil contamination was initially identified during the 1995 investigation activities.  Additional sampling is necessary to delineate the current extent of contaminated soils.  Additionally, soil sampling should be performed at the B-21 site to verify that the impacted soil material has been addressed during removal activities conducted in 1999.

Conduct additional soil sampling to determine the current extent of contamination.  Also, conduct verification sampling in the SWMU B-21 area to confirm that all contaminated soil has been removed.

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

The boundary of SWMU B-20/21 area was surveyed by licensed surveyors in 1995.

Yes.

NA

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

The type of disposal area was identified by personal accounts of CSSA personnel, and by a memorandum on file at CSSA, describing SWMU B-20 as a demolition area in 1946.  SWMU B-21 was a small arms ammunition disposal area.  Due to the proximity of SWMU B-21 to SWMU B-20, the two areas were combined to create B-20/21.

Yes.  UXO sweeps and soil excavation was conducted at the site to determine the extent of the disposal activities.

NA

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

Information regarding design features was obtained during the Environmental Assessment (ES, 1993) and through visual observations during the field investigation.  All available information regarding the design of the disposal site is provided in Sections 1.1 and 1.2.

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 Sections 1.1 and 1.2.  This information is from the Environmental Assessment, records review, interviews, aerial photo review, 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 Sections 1.1 and 1.2 and in the reports listed in Section 4.0.

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.  However, a memorandum regarding the past activities at SWMU B-20 was found at CSSA.  All known information derived from the Environmental Assessment, records review, interviews, and visual observations at the site is provided in Sections 1.1 and 1.2.

Yes

NA

Contamination Characterization – Groundwater (B.3.C.1)

Characterize the vertical and horizontal extent of groundwater contamination.

Shallow groundwater was encountered during 1995 drilling activities at the site.  A sample of the groundwater collected from boring SB01 did not detect COCs above the reporting limits.  No shallow groundwater was encountered during drilling in March 2000.

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

NA

NA

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

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

Completed 59 surface soil samples, 10 soil boring samples, 8 sediment samples, 5 surface water samples, one groundwater sample and multiple UXO removal actions.

No.  Although numerous surface soil samples have been collected at the site, the current horizontal extent of contamination is not known due to all of the earth-moving conducted at the site during the sifting operations.  The vertical extent of contamination has been determined.

Conduct additional soil sampling as warranted to delineate current extent of soil contamination.  Also, additional UXO removal actions are required to address UXO items that may remain in the unsifted portion of the site.

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)).

These factors are discussed in the Soil Pile Disposition Assessment Report.

Due to the high pH of soils, leaching of metals will not readily occur.

No.

NA

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

See “Characterization of Environmental Setting – Soils” above.

No.

NA

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

Contaminants were determined to be at shallow depths and no impacts to shallow groundwater were identified.  Therefore, the contaminants appear static and no action is needed to define the direction of contaminant movement

NA

NA

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

Contaminated surface soils are not anticipated to migrate.

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 total of 13 soil borings have been drilled and sampled at the site, and organic vapors were monitored during the drilling.  Eight soil borings were redrilled in 2000 due to analytical problems.  All soil borings were properly abandoned.  Soil borings activities are outlined in Section 2.1.4.

Yes

NA

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

Figures of the site including locations of the soil borings and soil sifting activities are provided in Figures B20/21-1 through B20/21-5.

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

Perform all analyses in accordance with the AFCEE QAPP.

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

All “R” flagged data are considered unusable. Benzoic acid was flagged ‘R’ in four samples. However, as benzoic acid is not a constituent of concern, the four affected samples will not be used for data evaluation.  All other data are considered valid and usable.

Yes

NA

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

Characterize the extent of sediment and surface water contamination.

Collected 8 sediment and 5 surface water samples during 1995 investigation activities.  Isolated exceedances were detected in surface water in craters.

Yes

NA

Potential Receptors (B.3.D).

Identify potential receptors

Records regarding potential receptors at CSSA are very limited.  All known information derived from the Environmental Assessment, records review, interviews, and visual observations at the site are provided in Section 1.2

Yes

NA