MEMO

+--------------------------------------+-------------------------------+
| To:                                  | Copies:                       |
|                                      |                               |
| Victor D'Amato                       | Copies                        |
+--------------------------------------+-------------------------------+
| From:                                |                               |
+--------------------------------------+-------------------------------+
| Kim Egler                            |                               |
+--------------------------------------+-------------------------------+
| Date:                                | ARCADIS Project No.:          |
+--------------------------------------+-------------------------------+
| 14 November 2023                     | RN990230.0005.00001           |
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| Subject:                             |                               |
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| Validation of Wipe Samples from CCA  |                               |
| Treated Wood Collected April 13,     |                               |
| 2004                                 |                               |
+--------------------------------------+-------------------------------+

Two hundred and ninety-nine (299) samples were collected on April 13,
2004 from the CAA Treated Wood Minidecks located at the USEPA in
Research Triangle Park, North Carolina. These samples were
triple-extracted with 10 percent nitric acid by ARCADIS personnel and
submitted by overnight courier at ambient temperature on April 14, 2004
to STL Savannah, Savannah, Georgia. Samples were analyzed on May 7-8 and
11-13, 2004. This validation covers the samples submitted for arsenic
(As), chromium (Cr), and copper (Cu) analysis by USEPA Method 200.8
(ICP-MS, modified). This methodology was modified to utilize hydrogen
plasma, rather than argon, as classically performed. This modification
eliminates concerns over the formation of Ar^40^Cl^35^, which can create
a positive bias when measuring As.

**Sample Delivery Group (SDG) WIPE10, Project Number S443176**

[]{.mark}

SS-1315 through SS-1403

SS-1405 through SS-1614 (sample SS-1432 in this sequence is actually
SS-1432A)\
SS-1432B

Validation of this data was performed following the quality
assurance/quality control (QA/QC) criteria set forth in the "USEPA
Contract Laboratory Program (CLP) National Functional Guidelines (NFG)
for Inorganic Data Review," July 2002. The NFG have slightly different
criteria for some parameters than does Method 200.8. In these cases, the
more stringent criteria were used.

[]{.mark}

# Metals Inorganic Review

# I. Preservation and Holding Times

The samples arrived at the laboratory promptly and were analyzed within
the analytical holding time. The samples had been shipped at ambient
temperature after being triple-extracted in 10 percent nitric acid.
Although the NFG recommends maintaining aqueous samples at 4ºC±2ºC, no
action is specified for this condition, and no action was taken. The
Case Narrative included sample identifications and indicated that all
samples were analyzed at various dilutions for As, Cr, and Cu, due to
the abundance of these metals.

# II. ICP-MS Tune Analysis

As required, 100 ug/L (ppb) tune checks were run on the required
isotopes before each calibration. Each tune was run five times in a row,
exceeding the four times in a row criteria required by the method. The
percent Relative Standard Deviation (%RSD) was less than 5% for all
isotopes, and the mass calibrations and peak widths met control
criteria.

# III. Calibration

The instrument was successfully calibrated before these samples were
analyzed. The two, four-point calibrations ranged from 0.5 to 100 ug/L.

Initial Calibration Verification (ICV) samples were run immediately
following each calibration, and all three metal recoveries fell within
the 90-110% control limits. Continuing Calibration Verification (CCV)
samples were run at a frequency of 10 percent, and at the beginning of
the run and after the last sample, as required. All recoveries were
within established control limits.

The Contract Required Quantitation Limit (CRQL) sample, referred to as
the CRDL in the lab report, was run as the first sample in the run,
immediately preceding the Interference Check Samples (ICS), as
stipulated in the NFG. Although the NFG states that the CRQL should be
run at the beginning and end of each sample analysis run and every 20
analytical samples, the method has no such requirement. The recoveries
for As, Cr, and Cu were within control limits.

# IV. Blanks

An Initial Calibration Blank (ICB) was run following each ICV, and was
nondetect for any of the target metals. Continuing Calibration Blanks
(CCB) were run immediately following each CCV at a frequency of 10
percent, as well as at the beginning of the run and after the last CCV.
All of the CCBs were nondetect for the three metals, with the following
exceptions.

***\
***

***Samples analyzed May 7-8. 2004:\
***

[CCB]{.underline} [Metal Detected (ug/L)]{.underline} [Action Level
(ug/L)]{.underline}

CCB#12 As -- 0.106 0.530

CCB#17 As -- 0.151 0.755

CCB#19 As -- 0.106 0.530

CCB#20 As -- 0.100 0.500

***Samples analyzed May 11-13. 2004:***

[CCB]{.underline} [Metal Detected (ug/L)]{.underline} [Action Level
(ug/L)]{.underline}

CCB#3 As -- 0.153 0.765

[]{.mark}

However, all associated sample results were either nondetect for As or
were above the Action Level, and no action was required.

Because the samples were extracted prior to shipping to the laboratory,
there were no Preparation (Method) Blanks associated with these samples,
and the CCBs were used as the Method Blanks. Fifteen field blanks
(extraction fluid only) were included in this SDG. All but one of the
blanks detected Cu and/or Cr, and resulted in the following samples --
which fell below the associated Action Level -- being qualified as
nondetect:

Cr SS-1422, SS-1427, SS-1432A, SS-1448, SS-1450, and SS-1459

In addition, one 10 percent nitric blank was run (SS-1586) and was
nondetect for all three target metals.

# V. Inductively Coupled Plasma-Interference Check Sample (ICS)

Interference Check Samples (ICS) were run at the beginning of each of
the three runs, after the ICV, and were followed by a CCV and CCB, as
required. The recoveries fell within the control limits and gave no
indication of isobaric interferences.

# VI. Laboratory Control Sample (LCS)

Because the laboratory did not extract the samples, the CCVs were used
as the LCS samples.

# VII. Duplicate Sample Analysis

Duplicate samples -- like LCS samples -- are to be carried through the
entire preparation and analysis process. Because the laboratory did not
extract the samples, no duplicate analyses were performed.

# VIII. Spike Sample Analysis

Because the laboratory did not extract the samples, Matrix Spike (MS)/MS
Duplicate (MSD) samples could not be analyzed. Therefore, Post Digestion
Spike (PDS) samples were run at a frequency of 10 percent. All
recoveries were within control limits. Samples SS-1582, SS-1583,
SS-1584, and SS-1585 were spiked with 10,000 ug/L, 1,000 ug/L, 50 ug/L
and 1 ug/L of each metal, respectively. The accuracy criteria were met
for all of the spiked sample concentrations.

# IX. ICP Serial Dilution

Thirty serial dilutions were performed on samples from this SDG. The
following samples had recoveries which exceeded the 10 percent
acceptance criteria, and with sample results for the metal that were
more than 50 times the MDL. In all cases, the sample result for that
metal in that sample were qualified as estimated "J."

SS-1365 Cr

SS-1395 As and Cr

SS-1416 Cr

SS-1436 As

SS-1456 As, Cr, and Cu

SS-1466 Cr

SS-1566 Cr

SS-1607 As

For samples where one or more metal exceeded the 10 percent criteria,
but the result was less than 50 times the PQL, no action was taken.

[]{.mark}

# X. ICP-MS Internal Standards

All of the Internal Standard recoveries were within control limits.

# XI. Field Duplicates

The following primary and blind field duplicate samples were collected
as part of this SDG and were collected at a frequency of almost 10
percent:

[Primary Sample]{.underline} [Blind Field Duplicate]{.underline}

SS-1587 SS-1324

SS-1588 SS-1333

SS-1589 SS-1344

SS-1590 SS-1348

[Primary Sample]{.underline} [Blind Field Duplicate]{.underline}

SS-1591 SS-1352\
SS-1592 SS-1371

SS-1593 SS-1376

SS-1594 SS-1383

SS-1595 SS-1386

SS-1596 SS-1407

SS-1597 SS-1415

SS-1598 SS-1479

SS-1600 SS-1487

SS-1601 SS-1495

SS-1602 SS-1502

SS-1603 SS-1512

SS-1604 SS-1514

SS-1605 SS-1519

SS-1606 SS-1529

SS-1607 SS-1531

SS-1608 SS-1534

SS-1609 SS-1536

SS-1610 SS-1540

SS-1611 SS-1566

SS-1612 SS-1568

SS-1613 SS-1576

SS-1614 SS-1578

All RPD were well below the QC limit of 50% - a reasonable control limit
for wipe samples.

# XIII. Overall Assessment

The reported data meets the acceptance criteria established in the NFG
and associated methods and plans. Data quality is sufficient for its
intended use.