Table 9. Summary of findings from the fifth VOC
Table 10. Summary of findings from the sixth VOC
study--Effect of room temperature and oven dry-
study--Effect of oven drying on PTFE.
ing on PTFE.
a. Mean percent loss of analytes from test solution
due to sorption
Mean desorbed conc. (mg/L)
24-hr sorption
7-day sorption
after decontamination treatment
MNT TCE PDCB PCE
MNT TCE PDCB PCE
Treatment
MNT TCE PDCB PCE
% loss
1.8
17.9
29.3
39.6
3.2
51.8
60.2
76.4
Air dry 24 hr
0.002
0.037
0.034
0.062
Hot detergent wash,
LD
0.021
0.017
0.031
b. Mean desorbed concentration (mg/L) after
oven-drying (105C)
hot water rinse,
and air dry 24 hr
Time
in oven 24-hr sorb/24-hr desorb
7-day sorb/24-hr desorb
Hot detergent wash,
LD
LD
LD
LD
(hr) MNT TCE PDCB PCE
MNT TCE PDCB PCE
hot water rinse,
and oven dry 24 hr
0
0.014 0.092 0.101 0.119 0.024 0.101 0.113 0.108
MDL
0.001
0.004
0.005
0.007
1
LD 0.005 LD
LD <0.004 0.018 LD <0.010
4
LD LD
LD
LD
LD LD LD
LD
LD = less than detection limit.
MDL 0.001 0.003 0.008 0.009
LD =
less than detection limit.
lowed by oven drying (105C) did remove the re-
sidual contamination from these test pieces
First pesticide study--Effect of no treatment
(Table 9). This was not the case for the samples
For all three sorption/desorption times, all
that were air dried at room temperature for 24
three materials sorbed significant quantities of at
hours or the samples that were detergent washed
least some of the analytes (Table 11). Losses fol-
and then air dried for 24 hours (Table 9). Clearly
lowing 10 minutes' exposure were less than 10%,
the higher temperature facilitated diffusion of the
while after 24 hours' exposure losses were as high
organic penetrants out of the polymer matrix.
as 69%. Table 11 shows that there will be carry-
over of these contaminants if the materials
Sixth VOC study--Effect of only oven drying
receive no decontamination treatment.
In this study, the test pieces were oven dried
It is interesting that the stainless steel test
and did not receive any washing. Oven drying
pieces were the most sorptive material, and PTFE
for one hour was not sufficient to remove these
contaminants. However, oven drying at 105C for
was the least sorptive. Our previous studies
(Parker et al. 1990, Parker and Ranney 1994), with
four hours was sufficient (Table 10). This was true
even for the samples that had
Table 11. Summary of findings from the first pesticide study--Effect
been exposed to the test solution
of no treatment.
for one week, where losses of
TCE, PDCB, and PCE ranged
a. Mean percent loss of analyte from test solution due to sorption
10-min sorption
24-hr sorption
from 52% to 77% (Table 10).
Material Lindane Heptachlor Aldrin Dieldrin Lindane Heptachlor Aldrin Dieldrin
Thus, to remove volatile organ-
ics, extensive detergent washing
PVC
1.9
1.3
7.7
8.3
4.5
52.6
16.3
31.4
PTFE
2.3
0
5.2
7.3
0.3
37.1
15.0
16.5
and rinsing does not appear to be
SS
2.8
3.2
5.7
9.4
3.3
69.2
18.5
47.7
necessary, even for samples that
have been exposed to the test so-
b. Mean desorbed conc. (g/L)
lution for up to one week.
10-min sorb/10-min desorb
24-hr sorb/24-hr desorb
Material Lindane Heptachlor Aldrin Dieldrin
Lindane Heptachlor Aldrin Dieldrin
Pesticide studies
PVC
7.61
LD
3.91
3.99
9.01
5.31
6.61
31.2
PTFE
2.72
0.68
2.45
5.49
2.86
7.11
6.74
22.8
Tables A7A11 present the
SS
12.3
LD
4.57
2.62
17.4
4.09
10.4
36.9
raw data from these studies. In
these studies, the mean initial
24-hr sorb/10-min desorb
concentration of analytes ranged
Material Lindane Heptachlor Aldrin Dieldrin
from 576 to 5605 g/L for lin-
PVC
6.79
0.78
4.31
7.98
dane, from 0 to 96 g/L for hep-
PTFE
2.46
1.68
2.93
9.57
tachlor, from 160 to 625 g/L for
SS
12.8
LD
6.14
6.94
aldrin, and from 191 to 393 g/L
MDL
0.88
0.62
0.83
0.61
for dieldrin.
LD =
less than detection limit.
11
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