Environmental Engineering Reference
In-Depth Information
Table 2.8
Correspondence of As to iron accumulation, but not all iron-rich strata have much As
Tot a l As
after C/D
(mg kg
−
1
)
As in C/D
extr. (mg
kg
−
1
)(%)
Fe in C/D
extr. (mg
kg
−
1
)(%)
Depth (m)
and sample #
Tot a l As (mg
kg
−
1
)
Tot a l Fe (mg
kg
−
1
)
TCLP As
(mg L
−
1
)
9.8 (C)
4.0
<0.001
1.8
2.2 (55)
−
(28)
20,000
−
10.2 (C)
4.5
<0.001
3.6
0.9 (20)
(7.8)
178,000
10.5 (C)
5.0
−
<0.001
2.8
2.2 (44)
(24)
24,000
11.0 (C)
7.5
<0.001
4.5
3.0 (40)
−
(7.8)
180,000
2.0 (V)
13
<0.001
2.3
10.7 (82)
−
(41)
20,000
2.5 (V)
<0.001
24.0
16.0 (40)
−
(47)
40.0
36,000
4.9 (V)
<2
<0.001
<2
<0.1
−
(<0.1)
2,000
5.1 (V)
13.0
<0.001
6.1
6.9
−
(36)
42,000
7.0 (V)
7.0
<0.001
1.3
5.7 (81)
−
(25)
124,000
9.9 (V)
<2
<0.001
<2
<0.1
−
(<0.1)
680
10.0 (V)
<2
<0.001
<2
<0.1
−
(74)
6,800
10.1 (V)
5.2
<0.001
0.7
4.5 (86)
−
(81)
124,000
10.2 (V)
11.0
<0.001
0.3
10.7 (97)
−
(23)
114,000
3.0 (BH85)
<0.001
15.0
10.0 (40)
−
(14)
25.0
38,000
3.2 (BH85)
8.5
<0.001
3.5
5.0 (59)
−
(11)
55,000
3.6 (BH85)
2.8
<0.001
0.3
2.5 (90)
−
(7.5)
5,100
6.0 (BH85)
4.0
<0.001
1.2
2.8 (70)
−
(30)
25,000
Notes: All kaolinised strata have very little Fe (
light grey
) while all
dark grey
strata have high Fe;
Lowest As samples are in kaolinised strata;
C
Coffey Partners core samples;
V
van de Graaff pit
face samples;
BH85
CMPS&F core samples
and construction activities were allowed to proceed, with the excavated material
being able to be disposed of cheaply as “Clean Fill”.
2.7.3 Chromium in Soils
A large military base in Victoria was no longer needed by the Defense Department
and the land was to be redeveloped for future residential uses. The area was largely
situated on an extensive colluvial slope at the base of steep hills with gneiss and
biotite gneiss bedrock. The area has a dry climate with a mean rainfall of some
740 mm per year and pan evaporation of around 1,600 mm yr
−
1
. In the winter and
spring months, rainfall exceeds evaporation and some leaching occurs. The typi-
cal soils are Duplex soils with acidic redbrown B horizons (probably equivalent to
Dystric Cambisols). An environmental audit of the soils by consulting environmen-
tal engineers found in a number of soil samples that chromium exceeded the EIL
for that metal, so that in principle development could not go ahead. A follow up
investigation was carried out by a consulting soil scientists (van de Graaff, Private
Communication).
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