Table 3 (cont'd). Concentration (g/L) of metals found leaching from well casings.
d. Copper
e. Lead
Contact time, days
Contact time, days
Treatment
1
5
20
40
Treatment
1
5
20
40
CONTROL
LD
LD
LD
LD
CONTROL
17.3
18.6
18.7
17.9
CONTROL
LD
LD
LD
LD
CONTROL
17.8
18.4
18.9
17.8
CONTROL
LD
LD
LD
LD
CONTROL
17.5
18.1
19.0
18.3
17.5a
18.4a
18.9a
18.0a
X
X
<0.35
<0.35
<0.35
<0.35
% RSD
--
--
--
--
% RSD
1.48
1.31
1.01
1.28
PVC
0.39
LD
0.36
LD
PVC
16.3
14.1
9.24
12.0
PVC
LD
LD
0.74
0.44
PVC
15.2
14.5
14.0
9.34
PVC
LD
LD
LD
0.48
PVC
14.6
13.5
12.2
15.2
15.4b
14.0c
11.8c
12.2b
X
X
<0.36
<0.35
<0.48
<0.42
% RSD
--
--
--
--
% RSD
5.86
3.49
20.5
24.0
PTFE
1.6
LD
0.59
LD
PTFE
16.6
17.7
17.8
18.0
PTFE
0.50
0.37
0.41
0.39
PTFE
19.6
17.2
17.3
16.1
PTFE
LD
LD
0.62
LD
PTFE
15.7
17.5
20.1
19.1
17.3a
17.5a
18.4a
17.7a
0.54a
X
X
<0.82
<0.36
<0.36
% RSD
--
--
20
--
% RSD
11.6
1.32
8.26
8.52
FEP
1.8
LD
0.46
LD
FEP
15.8
15.7
16.9
14.6
FEP
0.41
LD
0.52
LD
FEP
15.9
15.1
16.1
14.4
FEP
0.36
0.46
0.87
0.37
FEP
16.0
15.1
14.7
13.9
15.9a,b
15.3b
15.9b
14.3b
0.85a
0.62a
X
X
<0.39
<0.36
% RSD
95
--
35
--
% RSD
0.50
2.09
7.23
2.37
FRE
LD
LD
LD
LD
FRE
8.58
9.62
8.42
5.12
FRE
LD
LD
0.35
0.38
FRE
10.7
11.2
9.76
8.03
FRE
0.57
LD
LD
LD
FRE
10.4
10.1
8.12
9.52
9.90d
10.3d
8.77d
7.56c
X
X
<0.43
<0.35
<0.35
<0.36
% RSD
--
--
--
--
% RSD
11.6
7.95
9.92
29.6
FRP
20
9.4
8.5
11
FRP
13.5
11.1
11.4
8.92
FRP
8.7
15
7.1
5.5
FRP
12.3
10.4
9.38
8.48
FRP
6.0
6.7
7.8
13
FRP
13.2
12.5
10.1
8.82
13.0c
11.3d
10.3c,d
8.74c
12b
7.8b
X
X
10
9.8
% RSD
66
39.4
8.8
40
% RSD
5.08
9.44
10.1
2.63
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.
The results from this study can be compared
with the results from a similar study (Hewitt 1989)
For the control samples, concentrations of Cr
that was concerned with metals leaching from
were all below the MDL (Table 3c). Concentra-
PVC, PTFE, and SS 304 and 316 casings. In that
tions of Cr in samples exposed to PVC, PTFE, and
study, Cd levels were highest in samples exposed
FEP were also generally below the MDL. Only
to the 316 SS. At the beginning of the study (days
samples exposed to FRE and FRP casings leached
1 and 5), the mean concentration of Cd in the sam-
concentrations of Cr that were consistently above
ples that were exposed to FRP casings was ap-
the MDL. However, there was no significant dif-
proximately half the mean concentration Hewitt
ference between the Cr concentrations of samples
observed leaching from samples exposed to the
exposed to these two materials.
316 SS. However, these high mean values for the
The highest concentration observed in any one
sample was 1.44 g/L (for a sample exposed to
316 SS were primarily due to the presence of one
high value among the replicates. Later in the study
FRP); the remainder of the samples had concen-
trations that were less than 1.0 g/L. These con-
(days 20 and 40), concentrations of samples ex-
centrations were all well below the MCL (100 g/
posed to the 316 SS were consistently lower than
the mean concentration of samples exposed to FRP.
L) set by the US EPA (1994) for drinking water.
6
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