Final Remedial Action Completion Report for the ... - Rvaap.org
Final Remedial Action Completion Report for the ... - Rvaap.org
Final Remedial Action Completion Report for the ... - Rvaap.org
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<strong>Remedial</strong> <strong>Action</strong> <strong>Completion</strong> <strong>Report</strong><br />
June 2008<br />
3.5.3 Field Quality Control Sampling Procedures<br />
Remediation of Soils and Dry Sediments at RVAAP 08-11 (LLs 1-4)<br />
Page 3-14<br />
At a minimum, field QC sampling procedures included <strong>the</strong> collection of duplicate samples at a<br />
frequency of one per 10 samples collected or as o<strong>the</strong>rwise specified by <strong>the</strong> field screen method<br />
vendor.<br />
3.5.4 Summary of Field Screen Results<br />
On-site field screening was per<strong>for</strong>med <strong>for</strong> metals, PCBs, and <strong>the</strong> explosives TNT and RDX prior<br />
to collecting <strong>the</strong> multi-increment samples <strong>for</strong> off-site confirmatory analysis. In general, <strong>the</strong><br />
results of <strong>the</strong> field screen analyses <strong>for</strong> metals and explosives worked well to guide confirmatory<br />
multi-increment sampling to produce results below cleanup goals with <strong>the</strong> exception of three<br />
multi-increment confirmatory sample locations (LL2ss-049-cs, LL3ss-072-cs and LL4ss-108-cs)<br />
<strong>for</strong> metals and one confirmatory sample location (LL1ss-038-cs) <strong>for</strong> TNT. The field screen<br />
results using <strong>the</strong> Ensys ® PCB Soil Test System were not as favorable as <strong>for</strong> <strong>the</strong> metals and<br />
explosives and tended to provide continuous suspect positive results.<br />
3.5.4.1 PCB Field Screening<br />
Field determinations of PCBs in soil samples were initially per<strong>for</strong>med through implementation of<br />
colorimetric analyses using <strong>the</strong> PCB Ensys ® Soil Test System. This is a pass/fail test and <strong>the</strong><br />
determination of PCBs concentration in <strong>the</strong> sample was determined by reading with a<br />
spectrophotometer. The color of <strong>the</strong> sample was compared to <strong>the</strong> reference standard provided<br />
with <strong>the</strong> field kit.<br />
As mentioned previously, <strong>the</strong> field screen results <strong>for</strong> <strong>the</strong> PCB Ensys ® Soil Test System<br />
continuously provided suspect positive results <strong>for</strong> PCBs. In order to provide an adequate<br />
comparison of <strong>the</strong> PCB field screen test kits to actual concentrations in <strong>the</strong> soils, Shaw submitted<br />
a pre-confirmation sample <strong>for</strong> laboratory analysis. The PCB field screen result indicated a<br />
concentration in <strong>the</strong> soil that was above <strong>the</strong> applicable cleanup goal; whereas, <strong>the</strong> laboratory<br />
result confirmed that <strong>the</strong> result was actually well below <strong>the</strong> cleanup goal, thus reducing <strong>the</strong><br />
confidence level <strong>the</strong> PCB test kits were providing.<br />
As a second alternative <strong>for</strong> evaluating PCBs in soil, Shaw utilized an on-site gas chromatograph<br />
(GC) with an electron capture detector (ECD). The ECD is an ultra sensitive GC that will only<br />
sense those substances that it is electron capturing, and is especially sensitive to halogens that<br />
contain chlorine elements such as PCBs. Through use of <strong>the</strong> GC-ECD, field screen results<br />
produced valid representation of PCB concentrations with a success rate of greater than 93%.<br />
Only one confirmatory sample (LL1ss-029-cs) of <strong>the</strong> 15 submitted <strong>for</strong> laboratory analysis <strong>for</strong><br />
PCBs reported an exceedance of <strong>the</strong> cleanup goal.<br />
3.5.4.2 TNT and RDX Field Screening<br />
Field determinations of TNT and RDX in soil samples were per<strong>for</strong>med through implementation<br />
of colorimetric analyses using <strong>the</strong> TNT or RDX Ensys ® Soil Test System. As with <strong>the</strong> PCB kits<br />
this is a pass/fail test. This test system provides <strong>the</strong> materials in pre-measured and pre-packaged<br />
<strong>for</strong>m eliminating labor intensive procedures of reagent preparation. The working range of <strong>the</strong><br />
field test <strong>for</strong> TNT and RDX is 2 to 40 mg/kg. This range is several orders of magnitude below<br />
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