EPA Response to Comments:
Description of Current Conditions Report, RCRA Facility Investigation Work Plan, and|
Comment No. |
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1 |
All Appropriate Work Plans |
All tables shall list the complete summary of analytical results. For example, some summary tables omit the analytical results for arsenic, beryllium, mercury, zinc, explosives, or volatile organic compounds. |
A small number of tables from previous investigations (prior to 1996) at SWMUs B-1, B-2, B-3, B-4, B-19, B-28, and O-1 were included in the encyclopedia. In these past tables, individual analytes that were not detected were not listed. However, if a complete group of analytes, such as explosives or volatile organic compounds, was analyzed for, that group was listed in the table with "—U1" listed for each sample’s results. All metals analyzed for are listed in the tables. In the future, a complete listing of all analytes will be included in the informal technical information reports (ITIRs) which will be included along with the technical reports in Volume 3 of the encyclopedia. Tables summarizing detected concentrations will be provided in the body of the technical reports. These summary tables will include a specific reference to an ITIR table for the full list of analytes. |
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2 |
All Appropriate Work Plans |
Some of the values listed as U2 (defined as the sample containing less than five times the amount of the analyte in the corresponding method blank) are relatively high values, thus indicating a problem with the reliability of the data (i.e., not certain of presence or absence of contaminants). These data should be reexamined and evaluated for their reliability and usability in the RFI process. |
As described above, a small number of tables from previous investigations (prior to 1996) were included in the encyclopedia. A review of those tables showed that cadmium, chromium, and nickel results were sometimes flagged with a "U2." As these investigations were conducted some time ago, and since QA/QC requirements have changed since that time, it will be difficult to gauge the usability of these data under today’s standards. Since further investigations are planned for these sites, Parsons ES proposes that re-examination only be undertaken where the data are to be used to demonstrate that the site has met closure requirements. This re-examination will be conducted during preparation of upcoming SWMU-specific RFI Reports. |
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3 |
All Appropriate Work Plans |
Sample quantitation limits were not reported. Sample quantitation limits should always be reported. |
Ed Brown is addressing chemistry aspect. Steve Rembish is working on the risk assessment aspect. |
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4 |
All Appropriate Work Plans |
The Work Plans shall clearly state that chemicals of concern will not be selected until after a cumulative potential risk for human health and an ecological risk evaluation is conducted. |
Several EPA comments address selection of chemicals of potential concern (COPCs) and selection of chemicals of concern (COCs). According to EPA’s Risk Assessment Guidance for Superfund, COPCs are chemicals that are potentially site-related and whose data are of sufficient quality for use in a quantitative risk assessment. During the planning of Solid Waste Management Unit Closures, accomplished in early 1996, Parsons ES investigated past waste generating activities at CSSA. The plans included a list of COPCs developed from past waste disposal records as well as process knowledge. At that time, a phased approach to investigation of CSSA’s numerous sites was also initiated. The first phase is an initial screening for contamination through limited sampling, geophysical surveys, and soil gas surveys, where appropriate. The second phase will be to identify the nature and extent of contamination, where detected. The majority of CSSA’s sites are solid waste disposal areas (trenches). Samples from these sites are analyzed for VOCs and metals. Where UXO is suspected, samples are also analyzed for explosives. Where it is suspected that waste was burned in the trench, samples are also analyzed for SVOCs. At any site in the screening phase of investigation, analyses include all analytes within the VOC, SVOC, and explosives analytical methods. If any analytes are detected at concentrations above risk-based standards, additional investigations will be conducted to determine the nature and extent. Phase 2 investigation at sites where SVOCs were detected may include analysis for PAHs. The list of metal analytes known to have been previously managed at CSSA include arsenic, barium, cadmium, chromium, copper, lead, mercury, nickel, and zinc. These metal analytes are included for all phase 1 (screening) investigations. If any of the metals are not identified during the phase 1 investigation, subsequent investigations will not include those specific metals not identified in the previous investigation. COCs, as noted in your comment, will only be selected after a cumulative potential risk for human health and an ecological risk evaluation is conducted. This approach will be detailed in the Risk Assessment Technical Approach currently being prepared. This approach will be included as part of the RFI Work Plan by its incorporation into Volume 1-6 of the encyclopedia. |
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5 |
All Appropriate Work Plans |
The footnote "NA" should be clearly defined in the summary tables. |
Concur. Footnote definition will be added. |
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6 |
The RFI Work Plan shall clearly state that a plan for conducting a risk-based evaluation inclusive of ecological receptors will be submitted. |
The plan for conducting a risk-based evaluation inclusive of ecological receptors will be included in the Risk Assessment Technical Approach document currently being prepared. According to Section B.4 of the 3008(h) order, the human health and ecological risk assessment is due 60 days after the RFI Report is approved. According to Section B.2 of the order, there were no specific requirements for including a plan for the risk assessment; however, a risk assessment technical approach document is currently being prepared. |
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7 |
CSSA shall ensure that all relevant compounds are analyzed for during the RFI activities conducted at the sites.
It should also be clearly stated in the Work Plans if the proposed sampling effort is a screening effort or a nature and extent determination.
Dioxins and PAHs shall be analyzed for in areas where the potential exists for their detection.
PAHs and pesticides/herbicides should be considered for analysis in the landfill/solid waste sites if there is the potential for their existence.
Vinyl chloride shall be included in the list of VOC analysis. |
The manner in which COPCs were identified is described in the response to comment #4.
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8 |
Surface soil samples are generally collected from the 0 - 6 inch interval below the ground surface. The proposed sampling intervals should also be based on the expected human health and ecological exposures in order to obtain the information necessary to conduct the risk assessment. |
Concur. All surface soil samples will be collected from the 0 – 6 inch interval. |
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9 |
Geophysical surveys are being proposed to aid in identifying areas to sample at the sites. The use of PID/OVA to find hot spots should also be employed in areas where VOCs are expected. If hot spots are not identified, then the use of standardized depths for sample location and depth should be utilized. |
Concur. A PID is typically used during drilling operations to determine if any depth intervals may contain contamination. If volatiles are detected, the standardized sample depth is modified so that a sample from the interval with the PID reading is collected. However, Parsons does not feel that use of a PID during geophysical surveys or surface soil sampling is appropriate due to the likely volatilization of any contaminants in surface soil. |
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10 |
Phthalate concentrations are consistently reported as measured concentrations. The origin of the phthalate concentration must be determined and explained. |
Additional sampling is planned at the sites where phthalates were detected to confirm or deny the presence of these analytes. This sampling plan is detailed in the rework work plans. |
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11 |
The overall purpose and the Data Quality Objectives for the collection of the wipe samples is not clear (e.g., Volume 1-1, SWMU I-1, page 25). It is unclear how these results will be evaluated and interpreted. This information must be added to the Work Plans. |
The purpose of the wipe sample is to screen (phase 1 investigation) for dioxins and furans inside the incinerator, where these contaminants are considered most likely to exist. If present, additional investigation (phase 2) for dioxins and furans around the incinerator will be recommended. The work plan will be revised to incorporate this information. |
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12 |
Volume 1-1, Work Plan, page 2-1 |
The work plan states that geophysical surveys will be utilized to determine the need for sampling. A complete rationale for sampling analytes and locations should be developed for each area to be investigated.
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Geophysical surveys are being conducted at several sites where subsurface waste is suspected. At these sites, soil borings will be drilled near any identified anomalies. Where only surface soil samples are being collected, sample locations will be based on what is known about the waste management activities at the site, stressed vegetation, visible waste (such as ampoules at the B-23A site), or any other features indicative of waste. Copies of the closure reports will be included in updates to CSSA’s encyclopedia which will be provided to EPA, TNRCC, AFCEE, and administrative record copies at the public library. |
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13 |
Volume 1-1, Work Plan, page 2-4, 4th paragraph |
The report has the wrong citation for TNRCC Risk Reduction Rules. The chapter citation in the report corresponds to the underground and above ground storage tank requirements. The correct chapter citation is 335. The full citation should read: 30 TAC 335.556 - 559. |
Concur. Citation will be corrected. |
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14 |
Volume 1-1, Work Plan, page 2-6, Table 2.2, Summary of Statistically Calculated Background Concentrations of Metals in Soil and Rock Samples |
There are concerns over some of the calculated values for arsenic, chromium, copper, lead, nickel and zinc. See related comments for Volume 2 (Background Metals Levels). |
See Response to Comment #37. |
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15 |
Volume 1-1, page 4-2, Figure 4.1, Project Schedule |
The project schedule should be updated to reflect the actual dates. |
A very detailed project schedule was provided in the second Quarterly Progress Report, which is also included in Volume 1-1. Section 4 will be revised to remove Figure 4.1, and refer the reader to the schedule in the Quarterly Progress Report. |
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16 |
Volume 1-1, Work Plan, page 8-9, Table 8.3.1 Analyses to be Performed on CSSA Monitor Wells |
What is the rationale for not including SVOCs and pesticides/herbicides in the list of analyses? The analytes must be included, or a rationale must be presented to clearly show that the analytes will not be detected. |
The groundwater list of analyses began with VOCs upon discovery of PCE in well 16. VOCs has been monitored since 1991, and based on the results, a reduced list of VOC analytes of concern was approved by EPA in August 1999. Metals were added in 1995, 1997 and 1999, and will continue to be monitored. SVOCs and pesticides/herbicides were not recorded as being disposed of in the two known groundwater contamination source areas, B-3 and O-1. However, as CSSA doesn’t have records that explictly state exclusion of these compounds, SVOCs and pesticides/ herbicides can be added for 1 year of groundwater monitoring. If no SVOCs, pesticides, or herbicides are detected, then it will be proposed that these analytes be taken off the list of analytes to be monitored. |
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17 |
Volume 1-2. Checklist for Revision Number 1, September 1, 1999 |
The following items were not included: Table B3-2, Figure B23-1, RL83 Interim Measures Work Plan Addendum, SWMU B-32 Chronology, Chronology for SWMU B-33. This information should be re-submitted. |
These items will be included in Revision 3. |
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18 |
Volume 1-2, SWMU B-1, page 4 |
Soil samples did not include the 0 - 1 foot soil interval. Additionally, the soil intervals varied widely in depth from 1.0 - 4.0, 14.0 - 15.0, to 29.0 - 30.0 feet below ground surface. It is recommended that a PID/OVA be utilized to help determine hot-spot locations. If hot spots are not found, then the use of a standardized depth for sampling locations/depths should be utilized. |
Concur. The work described in the referenced work plan was initially completed in 1996; however, samples were analyzed by ITS Laboratory. A draft plan for rework was submitted to you on January 5, 2000. The rework work plan notes that: "If PID readings indicate that VOCs are present, then the subsurface soil sample from that interval will be submitted to the laboratory for analysis." |
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19 |
Volume 1-2, SWMU B-3 |
The proposed sampling locations/depths may be a concern. The rationale for sampling points should be provided. A sampling location map should also be provided. |
Since SWMU B-3 is in the treatability study phase of work, documents pertaining to work at this site are included in Volume 4 of the encyclopedia. The work plan in that volume describes the rationale for sampling points and includes several sampling location maps. |
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20 |
Volume 1-2, SWMU B-4, Item 5 |
This statement contains a typographical error. The word "without" should be removed. |
Concur. Corrected page will be included in Revision 3. |
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21 |
Volume 1-2, SWMU B-5 |
What is the rationale for SVOCs being excluded in Field Effort 1 but included in Field Effort 2? Provide the rationale. |
This typographical error will be corrected in the next update to the Encyclopedia. No analysis of SVOCs is planned at this site. |
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22 |
Volume 1-2, SWMU B-23A |
Due to the multiple locations of the ampules across this site, additional borings and monitoring will be necessary at this SWMU. Sample locations should be biased around the ampules to ensure that the site is characterized. |
As at other sites, a phased approach is planned for investigation of this site. The first phase, documented in RL83 Work Plan Addendum, includes surface soil sampling with locations biased around the ampules. Recommendations for further work will be included in the technical report for the site. |
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23 |
Volume 1-2, RL83 |
Explosives were not included in the list of analytes. Provide the rationale for the list of analytes. |
CSSA requests clarification on this comment. What site does this comment refer to? |
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24 |
Volume 1-2, SWMU B-31/B-32/B-33 |
Which metals will be included in the analyses? Provide the rationale for the list of analytes. |
Initially, samples collected at these three sites were analyzed for arsenic, barium, cadmium, chromium, copper, lead, mercury, nickel, and zinc. The basis for selection of these metals is described in the response to comment #4. These analyses were conducted by ITS Laboratory as part of the RL17 Project (in accordance with the RL17 Work Plan). Subsequently under the RL33 Project, the waste material (shot containing lead and sand) was excavated and disposed of. Since the initial samples collected at the site showed elevated (above background) concentrations of copper, lead, mercury (B-33 only), and zinc, samples collected after the pits were excavated were analyzed for these metals only. However, as part of the ITS rework sampling, samples collected as part of the RL17 Project will be recollected and analyzed for the nine-metal suite once again. The RL33 samples with the reduced metals analyte list will not be recollected as they were collected at the bottom of the pipe trenches which have since been backfilled. |
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25 |
Volume 1-2, SWMU F-14 |
The final closure report should be included in the work plan. |
The final closure report is included in Volume 3-1. |
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26 |
Volume 1-2, SWMU Bldg. 43 |
SVOCs were not included in the proposed list of analytes. Provide the rationale for the list of analytes. |
Known waste management activities at SWMU Bldg 43 included use as a makeshift ammunition demolition facility used to burn miscellaneous solid waste and ammunition. Fuels potentially included chlorinated solvent, tetrachloroethylene, as well as other volatile compounds. There is no knowledge that SVOCs were disposed of within SWMU 43. |
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27 |
Volume 1-2, SWMU O-1, Tables O1-1 and O1-2 |
There appears to be an inconsistency in the list of metals analyzed for SWMU O-1. Table O1-1 excludes arsenic, beryllium, mercury, and zinc and Table O1-2 excludes beryllium, nickel and zinc. Provide the rationale for the list of analytes. |
During prior investigations, (e.g., Well 16 Source Investigation, and other related investigations performed prior to 1996), analysis of contaminants were chosen either by analytical method capability, (i.e., EPA SW-846 Method 6010), or by EPA hazardous RCRA eight metals. Therefore, investigations prior to 1996 included metals which CSSA has no previous record or knowledge of being present in any waste generating activities on-site. All subsequent investigations (after 1995), including the establishment of background levels for all soil types known to exist at CSSA, included the nine metals of potential concern determined through known past waste management activities. During the closure/investigation activities, metal analysis included the CSSA nine metals of potential concern. Subsequent investigations included only those metals which were identified during the previous investigation(s). |
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28 |
Volume 1-3, AOC 49, RFI Work Plan Addendum, page 1 |
The work plan addendum states that 3 soil borings will be completed to characterize the subsurface soils surrounding any detected anomaly. Two soil samples are proposed to be collected from each soil boring at the total depth of 10 feet for each boring. A PID/OVA instrument should be utilized to detect hot spots. If hot spots are not found, then the use of a standardized depth for sampling locations/depths should be utilized. |
Concur. The following statement will be added to the RFI Work Plan: "If PID readings indicate that VOCs are present, then the subsurface soil sample from that interval will be submitted to the laboratory for analysis. If there are no PID readings throughout the total depth of the boring, samples will be collected at depths of approximately 5 and 10 feet." |
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29 |
Volume 1-3, AOC 53, RFI Work Plan Addendum, page 1 |
Grab surface soil samples are proposed to be collected at approximately 2 feet and analyzed for metals and pH. Surface soil samples should be collected at the 0 - 6 inch below ground surface interval. |
Concur. The RFI Work Plan Addendum for AOC 53 will be revised to reflect a 0-6 inch surface soil sampling depth. |
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30 |
Volume 1-3, AOC 54, RFI Work Plan Addendum, page 1 |
Grab surface soil samples are proposed to be collected at approximately 2 feet and analyzed for metals and pH. Surface soil samples should be collected at the 0 - 6 inch below ground surface interval |
Concur. The RFI Work Plan Addendum for AOC 54 will be revised to reflect a 0-6 inch surface soil sampling depth. |
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31 |
Volume 1-3, AOC 67, RFI Work Plan Addendum, page 1 |
Which metals will be included in the analyses? Provide the rationale for the list of analytes. |
Metals (arsenic, barium, cadmium, chromium, copper, lead, mercury, nickel, and zinc) will be added to the list of analytes for this site. The rationale for this list of metals is described in the response to comment #4. |
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32 |
Volume 1-4, Sampling Analysis Plan, Addendum 1, RL33 Addendum, page 3, Section 2.2 Field Screening |
The analysis of amines and nitrates should be included in the list of compounds for evaluation of the residual concentrations of explosives. |
The comment addresses a list of analytes associated with the
immunoassay test kits. These samples were collected during previous
investigations at the B-20 site to help identify explosives contamination.
However, soil samples were also collected for laboratory analysis. These
samples were analyzed for nitroaromatics and nitramines using the SW8330
method which includes the following analytes: Rework sampling for nitroaromatics and nitramines analysis is currently planned for the B-20 site, as described in the rework work plan. |
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33 |
Volume 1-4, Sampling and Analysis Plan, RL53 Addendum, Procedures For Sampling Activities, page 1 |
It is stated in the report that due to cost constraints, no corresponding QA/QC samples will be collected for PCBs or dioxins . A level of QA/QC should be proposed and conducted to ensure that the data collected is usable. |
It was inaccurately stated that no QA/QC samples would be collected for PCBs or dioxins wipe samples. The laboratory will analyze a method blank, laboratory control sample (LCS), and an LCS duplicate sample to ensure that accuracy and precision requirements will be met. These LCS/LCSD QA/QC samples will verify that the laboratory is following the correct procedures stated in the SOP and the method blank will ensure that no cross-contamination has taken place. |
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34 |
Volume 1-4, Sampling and Analysis Plan, RL 53 Addendum, Constituents of Concern and Analytical Methods, page 2 |
This information is not complete. It should, at a minimum, also include method detection limits, practical quantitation limits/estimated quantitation limits, and reporting limits. Provide the missing information. |
Since laboratories conduct new method detection limit (MDL) studies on a regular basis and the values are subject to change, MDLs will be included in the informal technical information reports (ITIRs) which will be submitted along with the technical reports. AFCEE reporting limits (RLs) are listed by method in the AFCEE QAPP (included in Volume 1-4). In accordance with the AFCEE QAPP, laboratories do not report practical quantitation limits (PQLs). |
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35 |
Volume 1-4, Sampling and Analysis Plan, RL 74 Addendum, Table 1. Constituents of Concern at O-1 and Methods of Analysis, page 2 |
There appears to be an inconsistency in the list of metals analyzed for SWMU O-1. Table O1-1 excludes arsenic, beryllium, mercury, and zinc and Table O1-2 excludes beryllium, nickel and zinc. Provide the rationale for the list of analytes. |
Please see response to comment #27 |
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36 |
Volume 1-6. Community Relations Plan, page C-1 |
The correct mailing address for Mr. Lyssy is U.S. EPA, Superfund Division, Mail Code 6SF-LT, 1445 Ross Avenue, Dallas, Texas, 75202. |
This correction will be included in the next update to the Encyclopedia. |
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37 |
Volume 2, Background Metals Levels |
Some of the detected and calculated background concentrations are higher in magnitude than would appear reasonable (i.e., point of reference is EPA Region 6's list of background ranges in the Region 6's Human Health Media-Specific Screening Levels). The wide range of the detected concentrations or concentration variability could be a factor in the inflated calculated values for arsenic, barium, chromium, lead, nickel, and zinc. The EPA will be evaluating the site investigation data by comparing those data with the detected background concentration ranges rather than the calculated background concentrations. CSSA need not recalculate the background concentrations nor conduct any additional background sampling. However, the background concentration summary tables should clearly indicate the detected background concentration ranges. |
Parsons ES and AFCEE reviewed the EPA Region 6 list of background ranges in a document titled EPA Region 6 Human Health Medium-Specific Screening Levels (page 5, Region 6 EPA, June 1999). The table provided in that document is not a list of ranges for all metals. Concentration ranges are not provided for each metal. On page 5 of that document, there is a short discussion regarding inorganic background. The use of the word "typical" at the beginning of the 4th sentence of that paragraph is disturbing as nothing is provided to demonstrate how these "typical" EPA Region 6 background numbers were derived. As CSSA’s contractor is under contract to perform a risk assessment, it is imperative that a full understanding of the criteria to be used for comparison be understood. If the QA/QC for the resampling and analysis of some of the background is acceptable and the results are similar to previous results (See response to comment #38 below), then comparison to "regional" typical" background concentration ranges may be inappropriate. Without any information as to how these "typical" concentration ranges were determined an assessment is probably impossible at this time. The contractor must have direction on what methodology to use to perform a risk assessment, or the probability of not fulfilling contractual requirements rises. The contractor can seek relief from contractual requirements because the government (CSSA/AFCEE) did not provide specifications in the SOW that could be met (Previously closures were being sought under Texas Risk Reduction Standard 1 requirements). In addition, the schedule for completing the RFI would very likely be adversely affected. Further, CSSA performed the background study under the TNRCC Risk Reduction Standard’s rules. As CSSA is required to close sites under these rules and the background study was approved by the TNRCC, there is the possibility of acquiring state closure and then being required to remediate the clean closed site if the EPA’s screening "ranges" are used. Important to note is that there has been no demonstration showing that all the soils of Regions 6 are composed of the same mineralogical and metal content as the soils of CSSA. Geological evidence indicates that this is not the case. That makes it even more important to be able to assess whether or not the "typical" background methodology is applicable to the types of soil matrices that are found at CSSA. CSSA requests a copy of the method used to determine the "typical" background concentration ranges and access to the data sets used in building the data sets used in the calculations. This is needed in order to ascertain whether or not the soil matrix is similar. If the soil types were similar, it would be possible to perform a direct comparison. If one or more are dissimilar then the comparison criteria can be adjusted to take into account site specific differences. AFCEE is comparing several base background study results for Texas Air Force bases to CSSA’s background values and the "typical" values provided by the EPA. A full comparison will take some time, but preliminarily it appears as if some values are above and some are below the "typical" values. If at the end of this assessment the results indicate that CSSA’s background metal concentrations are "atypical" then the EPA and CSSA can work to provide the best method for determining true site and base risk levels. CSSA requests that the EPA provide assistance and information to aid both CSSA and the EPA to meet these goals. |
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38 |
Volume 2, Background Metals Levels, Tables C-1 through J-2 |
The following are concerns in the information listed in these tables:
The data qualifiers of "F" and "B" were not defined in the tables.
"M" qualified data were used in the calculation of the 95% Upper Tolerance Limit. "M" qualified data is defined as a sample identified by the laboratory as not meeting QAPP requirements for one or more target analytes (see Volume 2, Appendix A, page A-1). |
As is typical in the soils in this region of Texas poor recovery of matrix spikes is a common problem. This problem is understandable when one looks at the matrix and the pH of the soils. The alkaline soils do not leach metals readily. In fact, treatability studies (electrokinetics, soil washing and phytoremediation treatability studies performed at CSSA) have shown that unless the pH of the soil is reduced significantly during treatment, the treatments do not work efficiently, thus producing poor mass removal rates. To acidify the soils sufficiently to remove metal contamination, the addition of inordinately large amounts of acid or other pH lowering compounds or elements are required. It therefore follows, that, as acid digestion of the samples is required, (fixed amounts, as per method extraction procedures) for chemical analysis as well as for remedial actions, it is not unreasonable to expect low recoveries. Method modification may be necessary to overcome this problem. But at this time, no identified procedure has been found. Technical people from AFCEE, AFCEE’s support contractors and the prime contractors and their subcontract laboratories are looking for a solution. If the EPA has any information on methods that can achieve better recoveries in the alkaline soils composed of clay, caliche and limestones, then it would be greatly appreciated if this information could be provided to CSSA. The effect this has on the site samples, as well as the background concentrations, is that "M" flagged data is biased low. This has a modifying effect to the previous comments from the EPA regarding the fact that the concentrations of certain metals are higher than that which the EPA would reasonably expect. The true concentrations may very well be even higher than the ranges provided in the background report. If the QA/QC for the analytical results are acceptable then this could present more of a problem than has already been considered. A large portion of the data for background is being resampled and analyzed because the previous data was analyzed by Intertech Testing Service (ITS). However, the current laboratory contacted the prime and is experiencing similar matrix effects. Until such a time as this rework is completed a full understanding of this problem is not possible. We will work with you and your technical people to solve the analytical problems so that confidence in the background concentration values will be high, thus lending better credence to a risk assessment. |
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