Table 12. Summary of findings from the second pesticide study--
Effect of a water rinse.
a. Mean percent loss of analyte from test solution due to sorption
10-min sorption
24-hr sorption
Material Lindane Heptachlor Aldrin Dieldrin Lindane Heptachlor Aldrin Dieldrin
PVC
4.4
9.6
5.6
11.0
4.4
49.1
21.7
29.7
PTFE
0.8
8.0
3.7
8.5
1.5
37.6
20.1
16.7
SS
2.7
8.7
3.7
10.8
4.0
66.8
27.4
44.2
b. Mean desorbed conc. (g/L)
10-min sorb/10-min desorb
24-hr sorb/24-hr desorb
Material Lindane Heptachlor Aldrin Dieldrin Lindane Heptachlor Aldrin Dieldrin
PVC
2.50
0.45
1.69
5.69
3.77
10.0
6.03
57.7
PTFE
0.70
1.15
1.29
8.28
1.06
12.1
8.57
35.8
SS
6.19
0.29
2.80
3.77
6.95
9.20
7.66
68.1
24-hr sorb/10-min desorb
Material Lindane Heptachlor Aldrin Dieldrin
PVC
1.97
1.28
1.81
12.2
PTFE
0.46
2.82
2.25
12.7
SS
5.75
0.89
3.18
11.7
MDL
0.35
0.14
0.53
0.83
Table 13. Summary of findings
trend (Tables A8 and A9). These results agree
from the third pesticide study--
with the findings of Sharom and Solomon (1981),
Effect of a hot water wash and
who found that sorption of the pesticide per-
rinse.
methrin was much more rapid for the nonperme-
Mean desorbed conc. (g/L) after
able glass surfaces than for the polymeric (PVC,
the following treatments*
PE, and Teflon) surfaces.
As would be expected, we also noted that de-
10-min sorb/10-min desorb
Material
Lindane
Aldrin Dieldrin
sorbed concentrations were highest in DI water
exposed to the SS test pieces. This also agrees
PVC
LD
LD
LD
with Sharom and Solomon's findings for desorp-
PTFE
LD
LD
LD
SS
LD
LD
LD
tion of permethrin from glass vs. polymeric sur-
faces.
24-hr sorb/10-min desorb
Material
Lindane
Aldrin Dieldrin
Second pesticide study--Effect of a water rinse
PVC
LD
LD
LD
Table 12 shows that rinsing the test pieces for
PTFE
LD
LD
LD
10 seconds with organic-free water was not effec-
SS
LD
LD
LD
tive in removing all the contamination, even for
the samples that were exposed to the test solution
24-hr sorb/24-hr desorb
Material
Lindane
Aldrin Dieldrin
only briefly (10 minutes). These results indicate
that these highly hydrophobic contaminants
PVC
LD
LD
LD
were sorbed in some way by the surface. Other-
PTFE
LD
LD
LD
SS
LD
LD
LD
wise, we would expect that rinsing would remove
MDL
0.53
0.41
0.73
most or all of the contamination, and the time for
desorption would not have affected desorbed con-
LD = less than detection limit.
* Heptachlor was inadvertently left out
centrations.
of the test solution.
Third pesticide study--Effect of a hot water
less hydrophobic organic contaminants (i.e., with
detergent wash and rinse
Kow values of 103 or less [munitions, VOCs]), have
Table 13 clearly shows that a hot water deter-
shown the opposite trend, with virtually no sorp-
gent wash and hot DI water rinse were effective
tion by the stainless steel test pieces. We initially
in removing the pesticides from all three test
thought that perhaps the samples had been misla-
materials, including samples that were given the
beled, but our next two studies show the same
longest exposure times.
12
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