Relationship between Cadmium Fractions Obtained by Sequential Extraction of Soil and the Soil Properties in Contaminated and Uncontaminated Paddy Soils
Table 1
Soil properties.
Soil
Soil typea
pH (H2O)
pH (KCl)
T-C
T-N
CEC
Exchangeable cations
Base saturation
Available phosphate
PAC
Particle size distr.
Free iron oxide
Oxalate extractable
Ca
Mg
K
Clay
Silt
Sand
Alo
Feo
Alo + 1/2 Feo
(g kg−1)
(cmolc kg−1)
(cmolc kg−1)
(%)
(mg kg−1)
(g kg−1)
(10−2 kg kg−1)
(g kg−1)
(g kg−1)
Uncontaminated-1
Fluvaquents
5.5
4.0
25.4
2.7
18.7
5.2
1.7
0.3
38.0
272
9.2
28.2
34.1
37.7
8.9
3.2
5.5
6.0
Uncontaminated-2
Fluvaquents
6.5
5.5
20.7
1.6
9.1
6.0
1.5
0.3
86.7
912
4.7
4.4
18.2
77.4
9.4
3.1
2.8
4.4
Uncontaminated-3
Endoaquands
5.8
4.8
62.1
4.4
25.8
9.8
2.7
0.8
51.7
434
10.5
38.4
31.5
30.0
8.5
4.7
3.8
6.6
Uncontaminated-4
Fluvaquents
5.8
4.2
15.8
0.9
8.7
2.7
0.7
0.2
41.7
188
3.8
8.6
12.3
79.1
5.5
2.0
1.8
3.8
Uncontaminated-5
Fluvaquents
5.9
4.3
24.4
1.8
16.1
6.3
1.4
0.3
49.6
327
5.8
16.4
19.7
63.9
5.0
2.7
1.6
4.3
Uncontaminated-6
Fluvaquents
5.5
4.0
22.9
1.8
13.3
3.6
1.1
0.4
38.5
148
6.0
13.8
17.8
68.5
3.1
2.2
2.2
4.4
Uncontaminated-7
Epiaquepts
5.5
4.1
33.6
2.2
20.6
5.4
2.1
0.2
38.1
145
9.8
22.8
23.7
53.5
10.9
3.4
4.7
8.1
Uncontaminated-8
Fluvaquents
5.5
4.0
25.5
1.6
17.6
5.4
2.0
0.5
45.4
160
7.7
17.5
30.4
52.1
11.0
2.4
5.4
7.9
Uncontaminated-9
Fluvaquents
6.1
4.6
19.6
1.7
9.9
3.8
1.3
0.3
54.8
236
5.6
11.6
19.1
69.3
9.2
3.9
1.9
5.8
Uncontaminated-10
Fluvaquents
6.0
4.4
18.8
2.1
15.2
7.2
2.6
0.3
66.2
224
7.2
18.8
23.7
57.6
9.6
2.4
4.9
7.3
Contaminated-1
Fluvaquents
5.7
4.5
32.0
2.6
14.3
4.3
0.9
0.1
37.0
570
6.6
14.1
17.3
68.6
7.7
3.1
2.9
4.6
Contaminated-2
Fluvaquents
5.5
4.3
32.6
2.5
10.6
3.1
0.8
0.2
38.4
277
4.3
10.1
15.0
74.9
4.7
2.2
2.0
3.2
Contaminated-3
Fluvaquents
5.6
4.7
46.3
3.7
17.6
6.0
1.9
0.6
47.9
708
7.6
14.8
22.1
63.1
9.1
4.1
4.7
6.5
Contaminated-4
Fluvaquents
6.1
4.5
32.6
2.6
12.1
3.4
1.0
0.3
38.8
401
4.2
14.4
14.7
70.9
4.5
2.7
2.9
4.2
Contaminated-5
Fluvaquents
5.9
4.9
37.8
2.8
15.4
6.2
1.3
0.3
50.7
514
6.6
10.2
23.5
66.3
6.3
3.7
2.2
4.8
Contaminated-6
Endoaquands
6.2
5.1
43.5
2.9
20.5
6.9
2.7
0.4
48.8
880
10.4
16.5
17.1
66.4
9.6
5.8
2.7
7.1
Contaminated-7
Endoaquands
5.6
4.5
48.2
3.7
17.4
5.2
1.2
0.5
39.6
349
9.0
23.7
31.6
44.7
11.4
4.6
3.4
6.3
Contaminated-8
Fluvaquents
5.7
4.5
12.7
1.0
8.2
2.0
0.6
0.2
34.0
143
2.9
5.6
7.8
86.6
12.3
0.9
3.4
2.6
Contaminated-9
Fluvaquents
5.9
4.7
15.2
1.2
8.3
2.9
1.1
0.3
51.8
175
3.6
7.0
11.7
81.3
9.7
1.0
3.1
2.5
Contaminated-10
Fluvaquents
5.9
4.9
33.5
2.6
18.4
7.9
1.9
0.2
54.7
528
8.5
22.3
36.2
41.5
13.9
4.2
5.4
6.9
Uncontaminated-AV
5.8
4.4
26.9
2.1
15.5
5.5
1.0
0.3
51.0
305
7.0
18.1
23.1
58.9
8.1
3.0
3.5
5.9
Contaminated-AV
5.8
4.7
33.4
2.6
14.3
4.8
0.8
0.3
44.2
455
6.4
13.9
19.7
66.4
8.9
3.2
3.3
4.9
T-C, total carbon; T-N, total nitrogen; CEC, cation exchange capacity; PAC, phosphate absorption coefficient. aClassified by Soil Taxonomy [23].
