Table 3 (cont'd).
c. Chromium
b. Cadmium
Contact time, days
Contact time, days
Treatment
1
5
20
40
Treatment
1
5
20
40
CONTROL
LD
LD
LD
LD
CONTROL
LD
LD
LD
LD
CONTROL
LD
LD
LD
LD
CONTROL
LD
LD
LD
LD
CONTROL
LD
LD
LD
LD
CONTROL
LD
LD
LD
LD
X
<0.12
<0.12
<0.12
<0.12
X
<0.059
<0.059
<0.059
<0.059
% RSD
--
--
--
--
% RSD
--
--
--
--
PVC
0.18
LD
LD
LD
PVC
LD
0.088
0.19
0.12
PVC
0.20
LD
0.13
0.13
PVC
LD
0.084
0.10
0.29
PVC
LD
LD
0.28
LD
PVC
LD
0.088
0.14
0.36
0.087a
0.15a,b
0.26b
X
<0.17
<0.12
<0.18
<0.12
X
<0.059
% RSD
--
--
--
--
% RSD
--
2.3
30
48
PTFE
0.26
LD
LD
LD
PTFE
0.064
0.083
0.090
0.084
PTFE
0.26
LD
LD
LD
PTFE
LD
0.092
0.063
0.10
PTFE
LD
LD
LD
LD
PTFE
LD
0.069
0.091
0.088
0.081a
0.081a
0.092a
X
<0.21
<0.12
<0.12
<0.12
X
<0.061
% RSD
--
--
--
--
% RSD
--
15
20
12
FEP
LD
LD
LD
0.23
FEP
0.061
0.089
0.15
0.13
FEP
0.13
LD
LD
LD
FEP
LD
0.15
0.091
0.15
FEP
0.21
LD
0.18
0.26
FEP
0.098
0.18
0.079
0.26
0.14a
0.11a
0.18a,b
X
<0.15
<0.12
<0.14
<0.20
X
<0.073
% RSD
--
--
--
--
% RSD
--
34
34
38
FRE
0.70
0.55
0.25
0.91
FRE
0.23
0.28
0.16
0.21
FRE
0.46
0.17
0.15
0.41
FRE
0.15
0.18
0.31
0.28
FRE
0.89
0.28
0.46
0.20
FRE
0.24
0.23
0.37
0.20
0.68a
0.33a
0.29a
0.51a
0.21a
0.23b
0.28b
0.23b
X
X
% RSD
9.0
59
54
72
% RSD
24
23
39
18
FRP
1.44
0.30
0.32
0.19
FRP
0.48
0.62
0.76
0.91
FRP
0.29
0.24
0.24
0.13
FRP
0.30
0.62
0.63
0.75
FRP
0.44
0.34
0.16
0.18
FRP
0.81
0.68
0.97
0.80
0.72a
0.29a
0.24a
0.17a
0.53a
0.64c
0.78c
0.82c
X
X
% RSD
87
17
33
19
% RSD
48
4.8
22
9.7
LD Values less than MDL.
LD Values less than MDL.
Values with the same letter for the same time were not signifi-
Values with the same letter for the same time were not signifi-
cantly different.
cantly different.
tween these materials. Concentrations in samples
All the values were well below the MCL of
2000 g/L set by the US EPA for drinking water
exposed to the FRP and FRE casings were signifi-
cantly greater than the other three casings (days
(US EPA 1994). The highest concentration found
was 311 g/L for a sample exposed to FEP; all the
5, 20, 40). However, concentrations in samples ex-
other samples had concentrations that were less
posed to FRE casings were always significantly
than 110 g/L.
less than those in samples exposed to FRP. Mean
concentrations for samples exposed to FRP ranged
from 9 to 14 times control values, while for FRE
Cadmium
they ranged from 3.6 to 4.8 times control values
For the control samples, concentrations of Cd
(Table 4).
were below the MDL (Table 3b). After one day of
In all cases, leached Cd concentrations remained
contact, only samples exposed to the two fiber-
well below the EPA's drinking water standards
glass casings had Cd concentrations above the
(US EPA 1994) of 5 g/L. Samples exposed to FRP
MDL. Subsequently, samples exposed to all five
casings were the highest and yet these were still
casing materials had concentrations above the
below 1.0 g/L. For samples exposed to the other
MDL. Generally, samples exposed to the PVC,
four casings, concentrations remained less than
PTFE, and FEP casings had the lowest concentra-
0.4 g/L.
tions and there was no significant difference be-
5
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