Final Remedial Action Completion Report for the ... - Rvaap.org

Remedial Action Completion Report
June 2008
Remediation of Soils and Dry Sediments at RVAAP 08-11 (LLs 1-4)
Page 3-15
the RVAAP cleanup criteria for TNT (1,646 mg/L) and RDX (838 mg/L). This test system is the
only screening method that has been approved for use at the RVAAP by the Ohio EPA.
Based on the evaluation of field and fixed-base laboratory results, the field explosives screening
method provided a valid representation of the presence or absence of TNT and RDX. A total of
15 multi-increment samples, including a duplicate, were submitted for laboratory analysis for
TNT. Only one location (LL1ss-038-cs) exceeded the cleanup goal yielding a greater than 93%
success rate for the test kit screening procedure. Four multi-increment samples were submitted
for RDX and the results for all four samples were below the cleanup goal, yielding a 100%
success rate.
3.5.4.3 Inorganics Field Screening
The majority of the remediation areas at LLs 1-4 were associated with elevated metals above
cleanup goals. The inorganic COCs at LLs 1-4 consisted of aluminum, antimony, arsenic,
hexavalent chromium, lead, and manganese. Manganese, lead and arsenic represented the
majority of the inorganic COCs. Ex situ field screening for the inorganic COCs was performed
using an Innov-X Systems X-Ray Fluorescence (XRF) instrument.
XRF to ICP Correlation Results
Prior to collecting the first confirmatory multi-increment samples, Shaw attempted to establish a
correlation for the primary inorganic COCs (manganese, arsenic, and lead) between the XRF and
the confirmatory laboratory results obtained by Inductively Coupled Plasma (ICP). The purpose
of the correlation was to see if the XRF technique would produce results comparable to the ICP
laboratory methods. If the XRF and ICP laboratory methods produced comparable results, the
XRF method could be considered reliable in rapidly determining the extent of contamination
before collecting confirmatory samples.
Shaw submitted a total of 15 discrete samples, including two duplicate samples, from the initial
excavation areas at LLs 1 and 4 and analyzed them using the XRF. Split samples were then
submitted to the off-site laboratory using the ICP analysis. The field screening samples were
directly comparable to the confirmatory laboratory samples because the field screening and
laboratory samples were the same homogenized source material. Differences between the ex situ
field XRF and the laboratory results primarily reflected differences in the two methods used on
the same material.
During past activities at the RVAAP, Shaw used a correlation percentage of less than 30%
difference as a solid indicator of reliable results between the XRF and ICP methods. This
percent difference provided positive results for those past activities and was considered a viable
comparison for the ongoing remediation activities. Table 3-3 provides a summary of correlation
results for the XRF and ICP methods for manganese, lead, and arsenic.
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