Table 8. Average concentration estimates (mg/
Table 7. Average concentration esti-
L) and standard deviations of total petroleum
mates (mg/kg) and standard devia-
hydrocarbons (TPH) for organic free (Milli-
tions of total petroleum hydrocarbons
pore) water spiked with gasoline during labo-
(TPH) for laboratory soil samples
ratory trials.
spiked with diesel fuel.
Target value
CRREL
Visual
HM 2000
Soil type and
target value
Visual
HM 2000
0.300.01
0.35 mg TPH/L*
0.25
<0.05
(86%)†
(71%)
Silt/Clay/Sand
[3%]**
7426
210 mg TPH/kg*
150
(72%)†
0.900.07
0.50.6
(35%)
1.0 mg TPH/L*
1.25
[35%]**
(90%)
(120%)
(50%)
98014
850 mg TPH/kg*
>500
[10%]
[160%]
(110%)
4.50.17
9.60.8
4.9 mg TPH/L*
2.5
[1%]
(92%)
(51%)
(200%)
Slit
[4%]
[8%]
340110
210 mg TPH/kg*
150
111.2
(72%)
(160%0
14 mg TPH/L*
10
>50
[32%]
(79%)
(71%)
930110
850 mg TPH/kg*
>500
[16%]
(110%)
1.90.1
6.92.9
2.0 mg TPH/L*
1.5
[12%]
(95%)
(75%)
(340%)
Slit/Clay
[11%]
[61%]
17087
210 mg TPH/kg*
150
160.8
(72%)
(81%)
20 mg TPH/L*
10
>50
[51%]
(80%)
(50%)
92033
850 mg TPH/kg*
>500
[6%]
(110%)
* n = 2.
[4%]
† Percent recovery relative to target value.
* n = 3.
** Relative percent difference.
† Percent recovery relative to target value.
** Percent relative standard deviation.
were reported during the technology demonstration, but
a preliminary data report was made available 3 days
later. Of the 90 samples distributed, 52 (58%) had been
are subjective, a precision assessment is not meaning-
analyzed on-site by the visual method, and 47 (53%)
ful. To estimate precision among sample duplicates, the
by the HM 2000. A final data report was available 12
relative percent differences (RPDs) were used. The
days after the end of the field exercise.
RPDs in Table 8 for the HM 2000 TPH estimates indi-
The TPH results for all of the samples distributed
cate that this measurement method may be less precise
during the field study can be found elsewhere (Hewitt
for water than for soil samples.
2000). Appendix A contains the visual and HM 2000
For one soil and one water matrix, seven sample rep-
values reported for samples contaminated with gaso-
licates were prepared and analyzed to estimate method
line and for all the QA samples (PE, matrix spike sam-
detection limits (MDLs) for the HM 2000 (Federal
ples, and field sample duplicates). Also included in these
Register 1984). The soil matrix was treated with a target
tables are the values produced by the CRREL refer-
concentration of 20 mg TPH/kg and the MDL was calcu-
ence method of analysis for those samples contaminated
lated to be 17 mg TPH/kg. Seven water PE samples at a
with gasoline.
certified concentration of 0.36 mg TPH/L were prepared
For the PE samples, the recoveries of TPH estimated
and analyzed, giving an MDL estimate of 2.3 mg TPH/L.
by the visual method and HM 2000 were all biased high,
Field study
ranging from 1.6 to greater than 4 times higher than the
During a two and one-half day field exercise, 90
certified values (Table 9). In particular, the average
values reported for the only PE water sample were very
samples were distributed for on-site analysis: 36 on the
high (more than 400% recovery). In contrast, the refer-
first day, 52 on the second, and 2 on the third. The HM
ence method provided average recoveries that were
2000 system experienced instrumental failures on both
within 5% of the accepted or expected values (Table
the first and second days of the field exercise. The sec-
9). For the matrix spike samples, average values within
ond failure could not be corrected in the field, so 38
25% of the expected concentration were attained for
samples were removed from the site for analysis at a
two out of eight of the duplicate sets by the visual method,
later date. Because of these problems, no TPH values
7
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