Ref. No. [UMCES] CBL 2013-020
ACT VS12-03
QUALITY ASSURANCE/QUALITY CONTROL
Quality Assurance (QA)/Quality Control (QC) procedures were performed in accordance
with the Test Protocols for this verification test, except where noted specifically within this
report. Changes as noted had no impact on the quality of the results. QA/QC procedures and
results are described below.
Quality Control Samples
Three types of QA samples were collected as part of our discrete reference sampling
protocols: laboratory duplicates, field duplicates, and field trip blanks. Lab duplicates were
repeated analysis from the same field collected sample. Field duplicates were two separate field
samples collected as close in time and space as possible and processed identically. Field trip
blanks were milli-Q DI that was carried into the field in a Van Dorn sampling bottle and then
processed identically alongside a normal reference sample. Only one reference sample/field
duplicate pair from Baltimore Harbor had a detectable hydrocarbon concentration and the
detection was only observed for the field replicate and not the reference sample pair. A
summary of the relative percent difference and precision within the QA samples for our ancillary
measurements of turbidity, chlorophyll, and CDOM are presented in tables 5-7. QA results for
hydrocarbon concentrations in field samples could not be computed, except for the Wave Tank
test, because almost all samples were below detection. The average relative precision (95%
confidence interval) among triplicate hydrocarbon determinations over all 5 trials was 20
percent, with a range of 1 – 40 percent for this test.
Table 5.
Turbidity results for laboratory duplicates and field duplicates of reference samples for the two
field test sites in Baltimore Harbor, site 2 in the Gulf of Mexico, and the Wave Tank experiments
performed at the Bedford Institute of Oceanography (BIO), Halifax, Nova Scotia. Samples were analyzed
on-site with a benchtop Hach 10AN turbidometer.
Site
QA Sample
Type
# obs
Mean (s.d.)
95% C.I.
Absolute
Precision
Average
Relative %
difference
Baltimore
Harbor
Field Blank
3
0.11 (0.05)
0.99
na
Lab Dup
2
4.1 (0.1)
0.09
6.1
Field Dup
7
2.6 (0.2)
0.19
13.3
Gulf of
Mexico
Field Blank
0
nd
1
nd
1
nd
1
Lab Dup
0
nd
2
nd
2
nd
2
Field Dup
5
3.2 (0.02)
0.02
1.6
BIO Wave
Tank
Field Blank
1
0.04
na
na
Lab Dup
7
0.69 (0.04)
0.10
6.9
Field Dup
5
1.37 (0.08)
0.12
8.6
nd
1
: no data; field trip blank was not collected during profiling
nd
2
: no data; lab duplicates for CDOM were not collected during profiling
na: not applicable
68
