The rare earth elements (REE) are of great interests due to wide industrial applications. In the present work, geochemistry of REE in the contaminated pond sediment of Ambagarh Chowki, cen-tral India is described. The concentration (n = 24) of La, Ce, Pr, Nd, Eu, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th and U was ranged from 16 - 119, 41 - 163, 4.1 - 28, 16 - 99, 0.7 - 2.7, 3.2 - 18, 2.7 - 16, 0.4 - 2.3, 2.2 - 13, 0.4 - 2.4, 1.1 - 6.1, 0.2 - 0.8, 0.9 - 4.8, 0.13 - 0.70, 6 - 25 and 0.46 - 1.86 mg/kg with mean value of 42 ± 9, 89 ± 13, 9.4 ± 1.9, 34 ± 7, 1.2 ± 0.2, 6.3 ± 1.2, 5.4 ± 1.0, 0.8 ± 0.1, 4.2 ± 0.8, 0.8 ± 0.2, 2.0 ± 0.4, 0.3 ± 0.1, 1.6 ± 0.3, 0.24 ± 0.04, 11 ± 2 and 1.14 ± 0.13 mg/kg, respectively. The concen-tration ratio of ∑LREE/∑HREE, La/Y and Th/U are discussed. The spatial distribution and sources of the REE are described.
Rare Earth Element Sediment Geochemistry Sources1. Introduction
The rare earth elements (REE) including actinide have wide industrial applications in several fields i.e. nuclear energy as fuel and modifier, organic synthesis as catalyst, ceramics as coloring agents, X-ray tubes as phosphors, etc. [1] [2] . The distribution of REE in various environmental materials i.e. soil and sediments was reported [3] - [13] . Recently, the health hazards of the REE were highlighted [14] [15] . The environment of the Ambagarh Chowki block, central India is seriously contaminated with As and heavy metals [16] . In this work, the geochemistry of the REE in pond sediments of Ambagarh Chowki block, Rajnandgaon district, central India is described.
2. Materials and Methods2.1. Study Area
Arsenic and other heavy metals are deposited in the environment of Ambagarh Chowki block, Rajnandgaon district, Chhattisgarh, India over area »3000 km−2. The Ambagarh Chowki block falls in a tribal belt with population of ≈0.1 million. This block covers 155 villages and towns which suffering with serious health hazards due to contamination of the environment with toxic elements. In this work, 24 ponds lie in different 11 villages (locations) of Ambagarh Chowki block were selected for the investigation of the REE contamination (Figure 1).
2.2. Sampling
The composite surface sediment sample (0 - 10 cm) was collected from five points in the equal ratio from each pond as prescribed in literature [17] . For the depth profile studies, the samples at the depth profile of 0 - 10, 10 - 20 and 20 - 30 cm of the Bhadsena pond was collected.
2.3. Analysis
The samples were dried, crushed and sieved out the particles of size ≤ 1 mm. A 0.25 g of each sediment sample was digested with 8 ml aqua regia in the closed microwave vessel for 15 min. An aliquot of the extract was diluted with deionized water for the further analysis. The Thermo Fisher ICP-OES and ICP-MS (Polish Geological Institute, NRI, Central Chemical Laboratory, and Warsaw) were employed for analysis of the elements. The NCS DC 73382 CRM sediment sample was used for the quality control. The background levels of the REE reported in the upper earth crust were used for computation of the enrichment factor (Ef) by using following equation [18] .
where, Xs, Als, Xe and Ale are concentrations of metal and Al in the soil and earth crust, respectively.
3. Results and Discussion
The sediment was found to be colored from light brown (LBr) to dark brown (DBr), Table 1. The pH value of the extract was ranged from 6.5 - 8.1 with mean value of 7.2 ± 0.2.
3.1. Concentration of Elements
The concentrations of 49 elements in 24 pond sediments are shown in Tables 1-4. The concentration of elements i.e. Fe, Al, Ca, Mg, K, Mn, Ti, Na, P, S, Ba, V, Zn, Cu, As, Ni, Cr, Co, Sr, Pb, Rb, Ga, Li, Be, Mo, Ag, Cd, Sn, Sb, Cs, Bi, Th, U, Sc, Y, La, Ce, Pr, Nd, Eu, Sm, Gd, Tb, Dy, Ho, Er, Tm, Tb and Lu was ranged from 25,400 - 65,900, 11,800 - 34,700, 1500 - 16,100, 1500 - 30,200, 1200 - 4500, 256 - 1660, 62 - 735, 90 - 830, 90 - 570, 50 - 790, 88 - 304, 29 - 166, 32 - 100, 28 - 89, 10 - 53, 19 - 340, 24 - 1298, 9 - 76, 10 - 69, 10 - 40, 12 - 46, 7 - 15, 5 - 18, 0.9 - 3.4,0.14 - 1.32, 0.07 - 2.36, 0.05 - 0.39, 0.8 - 2.6, 0.27 - 0.97, 0.5 - 2.2, 0.10 - 0.30, 6.1 - 25, 0.5 - 1.9, 3.0 - 25, 11 - 61, 16 - 119, 41 - 163, 4.0 - 28, 16 - 99, 0.7 - 2.7, 3.2 - 18, 2.7 - 16, 0.4 - 2.3, 2.2 - 13, 0.4 - 2.4, 1.1 - 6.1, 0.15 - 0.83, 0.9 - 4.8 and 0.13 - 0.70 mg/kg with mean value of 44842 ± 5133, 23813 ± 2819, 5133 ± 1418, 6850 ± 2581, 2708 ± 243, 759 ± 158, 254 ± 79, 355 ± 93, 268 ± 45, 285 ± 81, 196 ± 21, 84 ± 16, 63 ± 7, 52 ± 6, 22 ± 5, 75 ± 30, 177 ± 118, 30 ± 7, 26 ± 6, 23 ± 3, 26 ± 3, 11 ± 1, 12 ± 2, 1.6 ± 0.2, 0.63 ± 0.14, 0.67 ± 0.23, 0.13 ± 0.03, 1.5 ± 0.2, 0.44 ± 0.05, 1.2 ± 0.2, 0.15 ± 0.03, 11 ± 2, 1.1 ± 0.1, 11 ± 2, 20 ± 4, 42 ± 8, 42 ± 8, 89 ± 13, 9 ± 2, 34 ± 7, 1.2 ± 0.2, 6.3 ± 1.2, 5.4 ± 1.0, 0.77 ± 0.15, 4.2 ± 0.8, 0.8 ± 0.2, 2.0 ± 0.4, 0.27 ± 0.05, 1.6 ± 0.3 and 0.24 ± 0.04 mg/kg, respectively. Among them, the highest concentration of Fe was marked. They occurred in following decreasing order in the sediment: Fe < Al < Mg < Ca < K < Mn < Na < S < P < Ti < Ba < Ce < Cr < V < Ni < Zn < Cu < La < < Nd < Co < Sr » Rb < Pb < As < Y < Li < Ga » Th » Sc < Pr < Sm < Gd < Dy < Er < Yb » Be < Sn < Eu » Cs < U < Tb » Ho < Ag < Mo < Sb < Tm < Lu < Cd » Bi.
3.2. Concentration of REE
The concentration of the LREE (i.e. La, Ce, Pr, Nd, Eu and Sm) and HREE (i.e. Gd, Tb, Dy, Ho, Er, Tm, Yb
Concentration of major element in sediments, mg/kg
S. No.
Pond location
Color
Fe
Al
Ca
Mg
K
Mn
Ti
Na
1
Murethitola-1
LBr
62,700
31,400
5800
6300
2900
778
735
160
2
Murethitola-2
LBr
64,900
34,700
7100
6800
3000
956
586
540
3
Murethitola-3
RBr
32,700
17,200
1800
1700
2100
447
166
90
4
Netamtola-1
DB
54,700
32,200
9400
14,300
2500
892
394
630
5
Netamtola-2
B
48,000
32,200
12,500
9200
4000
1474
140
830
6
Netamtola-3
LB
53,800
30,000
16,100
9300
1300
959
455
740
7
Kaudikasa-1
DBr
49,800
30,600
7600
10,800
4000
1109
264
490
8
Kaudikasa-2
RBr
49,500
19,200
2000
2800
4500
467
254
180
9
Kaudikasa-3
LB
25,400
19,200
4700
4800
2400
256
64
220
10
Ghorda-1
Br
45,600
29,400
3700
7700
2900
1660
173
130
11
Ghorda-2
LB
41,000
28,600
5800
30,200
1600
1148
556
100
12
Ghorda-3
LBr
57,700
34,300
7600
17,900
1200
671
571
150
13
Metepar-1
Br
43,600
26,700
4800
6600
2000
856
105
110
14
Metepar-2
LBr
59,000
23,400
3400
4900
2200
878
313
730
15
Metepar-3
LBr
65,900
25,100
3600
5000
2900
540
320
270
16
Bhadsena
LBr
38,000
21,500
2100
2500
3000
350
68
340
17
Sonsaitola-1
LB
28,000
18,600
4800
3700
3200
694
62
280
18
Sonsaitola-2
LBr
28,000
14,100
2500
1800
3400
388
92
330
19
Sonsaitola-3
DBr
32,500
14,800
2500
2200
3800
435
98
600
20
Meregaon
Br
50,000
19,600
3100
2500
2200
1393
185
250
21
Joratarai
DBr
53,100
23,600
3300
5100
2700
853
133
360
22
Thailitola-1
LBr
26,900
11,800
2500
2600
2500
285
125
230
23
Thailitola-2
RBr
33,500
14,700
1500
1500
1700
369
163
140
24
Jadutola
LB
31,900
18,600
5000
4200
3000
350
73
630
Chemical characteristics of metal in pond sediment, mg/kg
S. No.
P
S
Ba
V
Zn
Cu
As
Ni
Cr
Co
Sr
Pb
1
300
80
217
144
76
64
40
51
45
30
29
17
2
380
380
259
160
88
71
17
58
64
44
39
24
3
160
70
129
59
42
53
33
29
39
13
12
20
4
430
790
179
86
90
89
16
133
301
41
42
24
5
420
540
304
87
80
71
12
85
136
39
54
22
6
170
70
150
166
53
49
12
43
56
33
69
12
7
340
600
264
96
88
73
20
108
232
42
30
27
8
320
320
212
48
100
48
53
30
61
18
16
40
9
220
400
179
50
50
41
15
55
120
18
21
23
10
160
360
300
79
52
47
12
196
635
76
17
39
11
570
90
218
67
54
36
10
340
1298
62
26
22
12
330
110
161
93
65
63
15
194
658
30
28
10
13
200
70
222
95
53
46
19
51
51
28
35
19
14
170
190
204
142
60
56
17
48
45
38
27
15
15
180
180
211
152
68
56
18
49
45
26
27
13
16
330
310
188
55
65
37
12
31
33
13
13
32
17
220
300
213
50
40
35
28
38
50
20
25
19
18
290
470
140
38
54
37
28
23
29
12
12
22
19
220
370
154
47
44
53
30
28
30
14
14
17
20
170
50
221
77
45
42
11
37
47
34
18
27
21
340
300
209
98
87
59
25
77
133
36
22
31
22
150
180
118
29
48
28
34
22
24
11
10
23
23
90
60
88
48
32
32
45
19
30
9
10
24
24
280
550
165
52
67
50
11
49
82
25
21
37
Chemical characteristics of minor element in pond sediment, mg/kg
S. No.
Rb
Ga
Li
Be
Mo
Ag
Cd
Sn
Sb
Cs
Bi
Th
U
1
32
14
14
1.57
0.67
0.15
0.12
1.4
0.46
2.18
0.3
13.2
1.64
2
23
15
13
1.35
0.40
0.69
0.26
1.4
0.35
1.41
0.1
7.2
0.77
3
27
8
8
1.47
0.85
0.13
0.05
1.4
0.43
0.98
0.3
15.7
1.36
4
12
11
17
1.16
0.27
0.73
0.39
1.2
0.51
0.52
0.1
6.1
0.65
5
22
12
14
1.98
0.40
0.92
0.19
2.1
0.4
0.95
0.1
10.2
1.36
6
15
10
11
1.06
0.24
0.07
0.05
1.1
0.42
1.00
0.1
6.5
1.01
7
29
12
17
1.55
0.52
1.60
0.21
1.7
0.52
1.23
0.1
8.0
1.14
8
46
11
9
1.68
1.32
0.16
0.11
1.3
0.59
1.63
0.2
9.3
1.12
9
20
7
9
1.29
0.26
1.70
0.16
1.5
0.27
0.97
0.1
10.1
1.04
10
39
13
18
2.55
0.92
0.56
0.14
2.6
0.50
2.09
0.1
14.1
1.42
11
15
9
18
0.86
0.18
0.26
0.06
1.0
0.35
1.19
0.1
7.6
0.74
12
14
12
15
1.39
0.14
0.19
0.05
2.0
0.3
1.08
0.1
8.0
0.46
13
28
10
14
1.47
0.20
0.13
0.06
1.3
0.34
1.69
0.1
10.1
1.34
14
21
12
11
1.1
0.68
0.78
0.13
1.1
0.38
1.08
0.1
7.3
1.15
15
31
13
12
1.14
0.81
0.69
0.10
1.3
0.39
1.32
0.2
8.7
1.01
16
44
12
12
3.37
0.84
0.6
0.10
2.6
0.43
1.46
0.2
24.9
1.86
17
25
8
9
1.58
0.39
0.19
0.06
1.4
0.34
1.1
0.1
11.5
1.08
18
28
9
7
2.07
0.84
1.07
0.14
1.8
0.45
0.8
0.2
14.4
1.17
19
31
9
7
2.08
0.95
0.79
0.10
1.9
0.45
1.05
0.3
13.3
1.17
20
22
10
9
1.32
0.96
0.52
0.06
1.3
0.36
1.02
0.1
10.4
0.95
21
27
11
14
1.33
1.19
1.06
0.19
1.5
0.97
1.26
0.2
7.9
1.2
22
23
7
5
1.28
0.63
0.75
0.08
0.8
0.42
0.83
<0.1
16.9
1.33
23
24
8
7
1.61
1.04
0.07
0.05
1.0
0.49
1.08
0.1
15.1
0.84
24
29
9
9
2.24
0.53
2.36
0.19
1.9
0.38
0.91
0.1
13.2
1.64
Concentration of lanthanide in pond sediment, mg/kg
S. No.
Sc
Y
La
Ce
Pr
Nd
Eu
Sm
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu
1
18.0
21.0
40.0
66.0
8.7
32.0
1.3
5.9
5.2
0.8
4.1
0.8
2.1
0.3
1.6
0.2
2
25.0
21.0
32.0
73.0
7.3
27.0
1.3
5.3
4.7
0.7
4.1
0.8
2.2
0.3
1.8
0.3
3
8.0
23.0
56.0
99.0
12.9
47.0
1.6
8.6
7.0
0.9
4.9
0.9
2.2
0.3
1.5
0.2
4
18.0
13.0
21.0
49.0
4.8
18.0
0.8
3.4
3.1
0.4
2.6
0.5
1.4
0.2
1.2
0.2
5
12.0
22.0
37.0
93.0
8.3
30.0
1.1
5.8
5.0
0.8
4.4
0.8
2.2
0.3
1.8
0.3
6
16.0
13.0
16.0
43.0
4.1
16.0
0.8
3.3
2.9
0.5
2.6
0.5
1.4
0.2
1.2
0.2
7
14.0
18.0
33.0
77.0
7.5
27.0
1.1
5.2
4.5
0.7
3.6
0.7
1.8
0.2
1.4
0.2
8
10.0
22.0
47.0
94.0
10.8
40.0
1.5
7.2
6.1
0.9
4.5
0.8
2.0
0.3
1.4
0.2
9
7.0
15.0
29.0
74.0
6.3
22.0
0.8
4.2
3.7
0.6
3.1
0.6
1.6
0.2
1.3
0.2
10
11.0
23.0
50.0
157.0
10.5
37.0
1.2
7.0
6.1
0.9
4.7
0.9
2.4
0.3
1.8
0.3
11
8.0
11.0
22.0
64.0
4.6
17.0
0.7
3.2
2.7
0.4
2.2
0.4
1.1
0.2
0.9
0.1
12
23.0
13.0
31.0
41.0
6.4
22.0
0.8
3.9
3.2
0.5
2.6
0.5
1.3
0.2
1.1
0.2
13
11.0
18.0
28.0
84.0
7.1
26.0
1.0
5.2
4.4
0.7
3.7
0.7
1.8
0.3
1.5
0.2
14
15.0
16.0
23.0
55.0
5.7
22.0
1.0
4.2
3.9
0.6
3.4
0.6
1.7
0.2
1.3
0.2
15
18.0
20.0
28.0
53.0
6.9
26.0
1.2
5.1
4.7
0.7
3.9
0.8
2.0
0.3
1.5
0.2
16
9.0
61.0
119.0
163.0
28.3
99.0
2.7
18.0
16.0
2.3
13.0
2.4
6.1
0.8
4.8
0.7
17
7.0
21.0
40.0
91.0
9.0
33.0
1.1
6.3
5.5
0.8
4.3
0.8
2.1
0.3
1.7
0.2
18
5.0
28.0
65.0
126.0
14.2
51.0
1.4
9.2
7.9
1.1
6.0
1.1
2.8
0.4
2.2
0.3
19
6.0
24.0
54.0
111.0
11.9
43.0
1.3
7.9
6.6
0.9
5.0
0.9
2.4
0.3
1.9
0.3
20
9.0
18.0
45.0
108.0
9.8
36.0
1.3
6.4
5.4
0.7
3.8
0.7
1.7
0.2
1.2
0.2
21
12.0
18.0
32.0
73.0
7.5
28.0
1.2
5.5
4.9
0.7
3.7
0.7
1.8
0.2
1.4
0.2
22
3.0
15.0
59.0
110.0
11.7
41.0
0.9
6.9
5.4
0.7
3.3
0.6
1.5
0.2
1.1
0.2
23
5.0
14.0
53.0
99.0
10.8
38.0
1.0
6.7
5.2
0.6
3.1
0.5
1.4
0.2
1.1
0.2
24
5.0
20.0
56.0
131.0
11.1
39.0
1.1
6.9
5.8
0.8
4.2
0.8
1.9
0.3
1.5
0.2
and Lu) was ranged from 82 - 431 and 8 - 46 mg/kg with mean value of 182 ± 30 and 15 ± 3 mg/kg, respectively. The ratio of LREE/HREE and Lu/Y was found to be in the range of 9 - 18 and 14 - 56 with mean value of 12 ± 1 and 27 ± 4, respectively. The concentration of REE and LREE/HREE and Lu/Y ratio were found to be higher than values reported in river sediments of the other regions of the World [3] - [11] .
The concentration of Th and U in the sediments (n = 24) was ranged from 6.1 - 25 and 0.46 - 1.86 mg/kg with mean value of 11 ± 2 and 1.14 ± 0.13 mg/kg, respectively. The Th/U ratio was ranged from 6 - 28 with mean value of 11 ± 2. The concentration of actinide elements in the studied area was found to be comparable to values reported in soil of other regions of the country [12] [13] (Figure 2).
3.4. Spatial Variations and Sources
The sediment samples were collected from 24 ponds which situated in 11 locations (i.e. villages) of Ambagarh Chowki block. The content of the REE in the pond sediments of 11 locations are shown in Figure 3. The highest content of the REE in the pond sediment of Bhadsena was observed. The REE content in sediment was found to increase as the depth profile was increased from 0 - 30 cm, may be due to geogenic origin and less binding with organic components of the sediment, Figure 4.
The correlation matrix of the REE is summarized in Table 5. All REE inclusive of Eu, Th and U are correlated well in the sediment, indicating origin from the similar sources likely to geogenic origin. They were partially correlated with elements i.e. Be, K, Rb, Cs, Mo, As, Sb, Bi, Sn, and Ag. Their negative correlations with elements i.e. Na, Mg, Ca, Ba, Sr, Al, Ga, V, Cr, Fe, Mn, Co, Ni, Cu, Zn, Cd and Pb were observed.
3.5. Enrichment
The Ef value for Sc, Y, La, Ce, Pr, Eu, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th and U in the sediment was ranged from 0.8 - 4.2, 1.5 - 9.4,1.7 - 13, 1.4 - 12, 1.7 - 13, 1.6 - 9,1.7 - 12, 1.6 - 12, 1.9 - 13, 1.6 - 11,1.6 - 11, 1.6 - 9, 1.4 - 9, 1.4 - 9, 1.4 - 8, 1.1 - 7, 1.1 - 11 and 0.4 - 3 with mean value of 2.5 ± 0.4, 4 ± 1, 6 ± 1, 5 ± 1, 5 ± 1, 4
Spatial variation of REE concentration in sediment of Ambagarh Chowki.
Spatial variation in concentration of actinide in sediment.
Depth profile studies of elements in Bhadsena pond sediment. D1 = 0 - 10 cm, D2 = 10 - 20 cm, D3 = 20 - 30 cm.
Correlation matrix of REE
La
Ce
Pr
Nd
Eu
Sm
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu
La
1.00
Ce
0.84
1.00
Pr
0.99
0.80
1.00
Nd
0.99
0.80
1.00
1.00
Eu
0.84
0.63
0.90
0.91
1.00
Sm
0.97
0.78
0.99
1.00
0.93
1.00
Gd
0.95
0.76
0.98
0.99
0.94
1.00
1.00
Tb
0.92
0.72
0.96
0.96
0.95
0.98
0.99
1.00
Dy
0.89
0.69
0.94
0.94
0.94
0.96
0.98
1.00
1.00
Ho
0.87
0.67
0.92
0.93
0.94
0.95
0.97
0.99
1.00
1.00
Er
0.85
0.65
0.91
0.91
0.93
0.94
0.96
0.99
1.00
1.00
1.00
Tm
0.83
0.64
0.89
0.89
0.90
0.92
0.94
0.98
0.99
0.99
1.00
1.00
Yb
0.81
0.61
0.87
0.87
0.89
0.91
0.93
0.97
0.98
0.99
0.99
1.00
1.00
Lu
0.83
0.63
0.89
0.89
0.90
0.92
0.94
0.97
0.98
0.99
1.00
1.00
1.00
1.00
± 1, 5 ± 1, 5 ± 1, 5 ± 1, 4 ± 1, 4 ± 1, 4 ± 1, 3 ± 1, 3 ± 1, 3 ± 1, 3 ± 1, 4 ± 1 and 1.7 ± 0.3, respectively. They were moderately enriched in the sediment. Their highest enrichments were marked in sediment of the Bhadsena village.
4. Conclusion
The REE were moderately enriched in all ponds and their enrichments were found to decrease as the mass number of the REE was increased. The concentration of all REE in the sediment was increased vertically, may be due to origin from the rock weathering. Their highest contents were marked in the sediment of Bhadsena village, Rajnandgaon, India.
Acknowledgements
We are thankful to the Alexander von Humboldt Foundation, Bonn for financial support to one of author: KSP. Our sincere thanks are also extended to the UGC, New Delhi for awarding Rajiv Gandhi Scholarship to students: BLS, KPR and SR.
Cite this paper
Bharat Lal Sahu,Keshaw Prakash Rajhans,Shobhana Ramteke,Khageshwar Singh Patel,Irena Wysocka,Irena Jaron, (2016) Geochemistry of Rare Earth Elements in Sediment of Central India. Journal of Environmental Protection,07,705-714. doi: 10.4236/jep.2016.75063
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