Table 1a. TNT was the major analyte present, with
1:2000) were required to obtain absorbances in
concentrations varying from sample to sample
the linear range of 0.01.0 absorbance units at 540
nm after reaction with the EnSys reagent.
for field analysis were highly colored even before
Duplicate field analyses for a given soil at sam-
reaction with the EnSys reagent. Extracts for
pling location 1 were in excellent agreement (mean
samples 2, 3 and 7 were yellow, extracts from
RSD was 3.9%), pointing out that field sample
sample 6 and the composites were orange, and
homogenization was adequate. Duplicate labora-
extracts of samples 1, 4 and 5 were dark brick red.
tory analyses varied to a greater extent than field
These colors are caused by the presence of
analyses (mean RSD was 11.1%), probably be-
phototransformation products of TNT in these
cause of the smaller sample size used for lab analy-
surface soils. The intensity of color before reac-
sis (2 vs. 20 g).
tion with the EnSys reagent correlated very well
Since TNT concentrations varied by such a large
with the TNT concentrations obtained by the colo-
amount from sample to sample, the data were not
rimetric on-site method. Reaction of the acetone
normally distributed and absolute variances were
extracts with the EnSys reagent resulted in the
not homogeneous. Since relative standard devia-
development of red solutions, indicative of the
tions were similar, this indicates that standard
presence of TNT. Substantial dilutions (as high as
deviations were proportional to concentration.
Table 1. Results from sampling location 1, Monite site.
a. Analytical results.
TNT on-site
Laboratory analysis (g/g)
analysis
(g/g)
Sample
TNB
TNT
2,4-DNT
Total
Discrete samples
1a
42,700
107
37,500
70
37,700
1b
36,900
104
45,000
--
45,100
2a
492
30
390
--
420
2b
507
30
382
--
412
3a
174
12
113
20
145
3b
154
11
116
--
127
4a
28,000
97
44,400
--
44,500
4b
27,600
--
41,200
--
41,200
5a
24,400
--
33,000
--
33,000
5b
24,400
--
22,400
--
22,400
6a
1,240
42
1,170
--
1,210
6b
1,310
33
1,200
--
1,230
7a
327
23
305
--
328
7b
334
17
227
--
244
mean
13,500
16,300
Composites
C1
12,900
--
11,800
--
11,800
C2
12,900
--
13,400
--
13,400
C3
13,300
--
13,600
--
13,600
C4
14,200
--
15,200
--
15,200
C5
13,000
--
13,900
--
13,900
C6
13,200
--
15,000
--
15,000
C7
12,500
--
16,100
--
16,100
mean
13,100
14,100
std. dev.
532
1,420
9
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