Table 6 (cont'd). Results from sampling location 6, Hawthorne AAP
site.
b. Statistical analysis of ammonium picrate concentrations
(g/g) for discrete and composite samples.
Discrete samples
On-site analysis
Laboratory total
Sample
Mean
Mean of logs
Mean
Mean of logs
1.447d†
1
28
5.8
0.763d
2
7.0
0.845f
<0.1
< 0.1f
3
6.1
0.785f
0.7
0.155f
4
81
1.909c
87.1
1.940c
5
4200
3.623a
4300
3.634a
6
1750
3.243b
1900
3.279b
7
13
1.114e
1.6
0.204e
†
Numbers designated with the same letter are not significantly different at the
95% confidence level.
ANOVA for log on-site analyses
ANOVA for log lab analyses
F ratio = 589***
F ratio = 923***
Error MS = 0.00451
Error MS = 0.00675
Least sign. diff. = 0.159
Least sign. diff. = 0.194
Linear correlation analysis for on-site analysis vs. lab analysis (r = correlation coefficient)
Slope
Intercept
r
untransformed, non-zero intercept
0.968
1.74
0.999
untransformed, zero intercept
0.967
0
0.999
log-transformed data
0.634
1.07
0.971
Results of paired t-tests for on-site vs. lab results
Means of seven discrete samples, t = 1.19(NS)
Means of log values for seven discrete samples, t = 2.34(NS)
Composite samples
On-site analysis
Laboratory total
n
7
7
mean value
970
1010
standard deviation
32.1
91.7
RSD
3.31%
9.10%
ANOVA comparing on-site and lab analyses
F ratio = 1.14(NS)
* Significant at the 95% level
*** Significant at the 99.9% level
** Significant at the 99% level
NS Not significant at the 95% level
below detection limits to over 4000 g/g for soils
We were not equipped to conduct ammonium
picrate screening in the field. However, an on-site
at sampling location 6 (Table 6a).
method has been developed for ammonium pi-
We found, using the on-site method, that du-
crate (Thorne and Jenkins 1995) and samples were
plicate analyses on samples homogenized in the
extracted in the laboratory with acetone and the
field had a mean RSD of 11.6%, and, using the
extracts subjected to the screening procedure as
HPLC method, a mean RSD of 11.9%. Unlike all
described in the Experimental section. Results of
other comparisons, aliquots of the same extract
the field analysis procedure and the lab (HPLC)
were used in these tests. Therefore, the two pro-
method, also conducted with these same acetone
cedures appear to have approximately equal pre-
extracts, were consistent and demonstrated that
cision. Field homogenization was clearly adequate
the ammonium picrate concentrations varied from
for site characterization. ANOVA, using log-trans-
22
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