Dames & Moore, 1999 - USDA Forest Service

Dcccmbcr 8, 1998
Lagoon Soil Samplcs, Fall 1998, Holden Mint
Page 3
2. Initial Calibration - Acceptable
3. Continuing Calibration - Acceptable
4. Blanks - Acceptable
5. Surrogate Recoveries
Samples DMLG-1-4, DMLG-2-7 % , DMLG-3-2, DMLG-3-4, and DMLG-5-4 were reextracted due
to low surrogate recoveries. The surrogate recoveries for the initial extraction and the reextraction are
tabulated below:
% Recovew Initial
24.3
% Recovew Reextract
66
Due to the low recoveries from the initial extraction, the results for data evaluation were selected
from the reextraction although past the method hold time (see discussion under Hold Time).
6. Laboratory Duplicate - Acceptable
7. Matrix SpikeIMatrix Spike Duplicate (MSIMSD)
A MSIMSD was performed on sample DMLG-3-2. Due to low surrogate recoveries for the
original, MS, and MSD samples, the QC set was reextracted. Surrogate recoveries were acceptable in
the reextracted QC set. However, the recovery of diesel spiked in the first MSIMSD was outside of the
laboratory control limits (38 - 160%) as the spike concentration was not recovered. The spike recoveries
from the reextracted MS and MSD were 73% and -41%, respectively. The sample concentration was
about 4X the spike level. Data are not generally qualified based on MSIMSD results alone. The
MSIMSD sample results'indicate a potential for variability related to sample DMLG-3-2. The data for this
sample was previously qualified as estimated based on surrogate recoveries. Additional qualification
based on MSIMSD results does not alter the estimated qualification already assigned.
8. ~aboratory Control SampleIBlank Spike (LCSIBS) - Acceptable
9. Field Duplicate
A field duplicate was not collected.
10. Target Compound Identification
The sample results reporied as diesel and motor oil in samples DMLG-1-4, DMLG-2-4, DMLG-2-
7%, DMLG-3-2, DMLG-3-4, DMLG-4-2, DMLG-4-4, DMLG-5-2, and DMLG-5-4 do not match typical
diesel or motor oil profiles, although the patterns are indicative of a heavy hydrocarbon component. The
diesel and motor oil reported in sample DMLG-1-2 are not indicative of typical diesel or motor oil
patterns.
11. Detection Limits - Acceptable
12. Type of Review - Summary
g:~olden\l998/dalavallvalY964.doc DAMES & MOORE