18th Final Quarterly Progress Report

Interim/Stabilization Measures

Interim/Stabilization Measures (I/SMs) are being conducted to mitigate a current or potential threat to human health and/or the environment. The IMs are estimated to represent approximately 30 percent of the required actions at CSSA. The IMs include Interim/Stabilization Measures WP (7 percent of IM), I/SM Implementation (70 percent of IM), and Reports (23 percent of IM). Based on information currently available at the end of Quarter 18, the IMs are approximately 70 percent complete.

Task I - Interim/Stabilization Measures Work Plan

Task Description

The Interim/Stabilization Measures WP includes:

1. A description of on-going and planned IMs;

2. A statement of the objectives of each interim/stabilization measure, including how the measure mitigates a potential threat to human health and the environment and is consistent with and integrated into any long-term remedy for CSSA; and

3. Proposed locations, design plans and specifications, construction, and operation and maintenance (O&M) requirements of the IMs, including a sampling and analysis plan (SAP).

Existing plans, which are included in CSSA’s Environmental Encyclopedia, are referenced to the extent possible.

Interim/Stabilization Measures include initial sampling and analysis of groundwater from off-post wells; sampling and analysis of groundwater in CSSA wells; identification of all off-post water wells located within ¼-mile of the facility boundary; evaluation of alternative measures and implementation of selected interim measures at SWMU O-1; closure of SWMU O‑1; characterization and determination of proper disposition of soil piles at SWMUs B-8, B-20, B-24, B-28, and the Demolition Dud (DD) Area; and implementation of the identified disposition method. Of the tasks listed, all have been completed with the exception of the soil pile work. In addition, continuation of on- and off-post groundwater sampling and analysis is being performed under the RFI phase of this project.

The Final Soil Pile Disposition Assessment (SPDA) was submitted in August 2003. A proposed disposition method of soil has been identified in the assessment under RL83. However, final implementation of the yet to be selected disposition method is not funded. Due to the volume of soil in these piles, and the need to address other more urgent environmental concerns, it is anticipated that funding may be spread over several years.

Activities this Quarter

Percent Complete

The I/SM WP task makes up approximately 7 percent of the I/SM phase and is 100 percent complete, based on the interim measures defined in the 3008(H) Administrative Order on Consent, located in Volume 1, Scoping Documents. Other investigation activities to be conducted are further discussed under RFI Activities, Investigation, Treatability Studies, etc., in the sections below. If further I/SM WPs are added to the scope of work in the future, the percent complete as stated will be adjusted.

Task II - Interim/Stabilization Measures Implementation

Task Description

SWMU O-1 –The Texas Commission on Environmental Quality (TCEQ) (formerly known as the Texas Natural Resource Conservation Commission [TNRCC]) approved closure of the land based portion of SWMU O-1 on December 3, 2001. Further investigation and possible remediation of the vadose zone and groundwater beneath SWMU O-1 will be conducted in future quarters. This I/SM task is complete.

Groundwater Sampling – Periodic sampling of on-post wells was initiated in 1991. Off-post water sampling began in 1995. Quarterly sampling of both on- and off-post wells began in 1999. This I/SM task is complete. Quarterly groundwater monitoring continues as part of the RFI task.

Off-post Well Survey (complete) – The final report was issued in August 2001 and is located in Volume 5, Groundwater of the Environmental Encyclopedia. This task is complete.

The Final SPDA Report was completed in Quarter 18. A bench-scale study of potential treatment technology (i.e., PIMS) will be continued during Quarter 19. Upon completion of the treatability study, a final disposition will be recommended. Planning and implementation will proceed once the final remedy has been selected for the excavated soils at SWMUs B-8, B-24, B-28, and DD, and funding is available. Soils from SWMU B-20 are already being addressed under the PIMS Stabilization Treatability Study (Task VI, RCRA Facility Investigation). As part of the treatability studies for the soil pile disposition assessment, an additional 22 tons of PIMS Apatite II material was purchased for stabilizing SWMU B-8 and DD soils for potential off-post disposal. Field efforts included the mixing of approximately 5 percent by weight of PIMS into 50 gallons of soil from SWMUs B-8, B-28, and DD. Samples were taken for metals analysis to determine the effectiveness of the treatment system. The treatability studies on SWMUs B-8, B-28, B-24, and B-20 and use of PIMS will continue next Quarter.

1. Percent Complete

The I/SM Implementation task makes up approximately 70 percent of the I/SM phase. This task is considered 59 percent complete, based on the current projected activities listed in Task II, Task Description. If investigation results at other sites indicate an immediate threat to human health or the environment, which warrant IM, the percent complete will be adjusted accordingly.

2. Summary of Findings

Samples of leachate generated from the PIMS Apatite II treated soil at SWMU B-20 were collected from site lysimeters. The samples were analyzed for some or all of these metals: arsenic, barium, cadmium, chromium, copper, lead, mercury, nickel, and zinc. Quarter 16 sampling events indicate leachate from the SWMU B‑20 soils contain no soluble lead and trace amounts of soluble barium, copper, nickel, and zinc. Lysimeter 4 was installed in non-treated soils and leachate analysis indicates approximately 350 micrograms of lead and measurable amounts of barium, nickel, and zinc. Samples were not collected during Quarter 17 due to lack of precipitation. All field treatability test results were documented in the final report for the PIMS field demonstration completed September 2003.

3. Summary of Changes

No changes associated with I/SM implementation occurred this reporting period.

4. Summary of Contacts

No contacts occurred during this reporting period.

5. Summary of Problems

No problems associated with I/SM activities occurred during this reporting period.

6. Actions Taken to Correct Problems

No actions to correct problems associated with I/SM activities were necessary this reporting period.

7. Projected Work for the Next Quarter

CSSA will continue with O&M activities for SWMU O-1 until a final remedy for the associated vadose and groundwater zone is complete. The continued O&M activities include maintaining the vegetative cover.

Treatability studies for the soil piles at SWMUs B-8, B-24, B-28, and DD will be continued in Quarter 19.

Monitoring of leachate generated at the test sites and maintenance of vegetative cover at the SWMU B-20 test site are expected to continue.

8. Copies of Daily Reports, Inspection Reports, Data, etc.

There were no reports provided during this quarter related to I/SM.

Task III - Reports

Task Description

Reports associated with the I/SM include quarterly progress reports, environmental cleanup reports, groundwater monitoring reports from one sampling event, and an I/SM report. This quarterly progress report is submitted as part of this task.

Reports required under the I/SM section of the Order are submitted in three phases. The first phase is a baseline report, the second phase are progress reports, and a final report upon completion of the project. This quarterly progress report fulfills the requirement for an I/SM progress report for activities including long-term operation, maintenance, and monitoring at CSSA.

Activities this Quarter

I/SM activities are reported in this quarterly progress report. The Final SPDA Report and the PIMS field demonstration efforts were the only reports for the I/SM portion of work generated this quarter.

1. Percent Complete

This task makes up approximately 23 percent of the I/SM phase. This task is approximately 94 percent complete based on the current projected activities listed in Task III, Reports. If investigation results at other sites indicate an immediate threat to human health or the environment so that I/SM activities are required at additional sites, the percent complete will be adjusted accordingly.

2. Summary of Findings

No findings associated with progress reports or I/SM reports are submitted this reporting period.

3. Summary of Changes

No changes associated with progress reports or I/SM reports occurred this reporting period.

4. Summary of Contacts

No contacts related to quarterly progress reports or I/SM Reports were made during this reporting period.

5. Summary of Problems

No problems were associated with IMs reporting this quarter.

6. Actions Taken to Correct Problems

No actions to correct problems associated with I/SM reporting were necessary this reporting period.

7. Projected Work for the Next Quarter

Continuation of the treatability studies for SWMUs B-8, B-24, B-28, and DD associated with determining the proper disposition of subject soils will be continued in Quarter 19.

8. Copies of Daily Reports, Inspection Reports, Data, etc.

No daily reports, inspection reports, or data related to the I/SM report were generated during this reporting period.

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