40
P. Lazo et al.
5
4
3
2
1
0
10
8
6
4
2
0
S
0 . 4 7 2 7 9 5
R-Sq
95.1%
R-Sq(adj)
95.0%
La
C e
Regression
95% CI
95% PI
Fitted Line Plot
Ce = - 0.0745 + 1.925 La
5
4
3
2
1
0
1.0
0.8
0.6
0.4
0.2
0.0
S
0 . 0 7 6 2 5 4 4
R-Sq
81.9%
R-Sq(adj)
81.5%
La
S m
Regression
95% CI
95% PI
Fitted Line Plot
Sm = 0.00786 + 0.1495 La
5
4
3
2
1
0
0.14
0.12
0.10
0.08
0.06
0.04
0.02
0.00
S
0.0081964
R-Sq
91.8%
R-Sq(adj)
91.6%
La
Tb
Regression
95% CI
95% PI
Fitted Line Plot
Tb = - 0.003732 + 0.02528 La
5
4
3
2
1
0
0.6
0.5
0.4
0.3
0.2
0.1
0.0
-0.1
S
0 . 0 6 4 4 6 5 5
R-Sq
72.5%
R-Sq(adj)
71.9%
La
Yb
Regression
95% CI
95% PI
Fitted Line Plot
Yb = - 0.01677 + 0.09649 La
5
4
3
2
1
0
4
3
2
1
0
S
0 . 4 1 2 2 6 8
R-Sq
68.1%
R-Sq(adj)
67.4%
La
Sc
Regression
95% CI
95% PI
Fitted Line Plot
Sc = - 0.2191 + 0.5547 La
5
4
3
2
1
0
0.5
0.4
0.3
0.2
0.1
0.0
S
0 . 0 4 3 4 7 6 1
R-Sq
77.8%
R-Sq(adj)
77.3%
La
U
Regression
95% CI
95% PI
Fitted Line Plot
U = - 0.00203 + 0.07501 La
Fig. 3.10 Linear regression plots of La versus Ce, La versus Sm, La versus Tb, La versus Yb, La
versus Sc, and La versus U
3.4.8 Strontium, Sr
Strontium is a naturally occurring element that is present in rocks, soil, dust, coal,
oil, water, air, plants and animals, and is found in the form of stable radioactive
compounds in the air dust particles (ATSDR 2004). Its content in the earth’s crust
goes up to 0.02–0.03% (ATSDR 2004), in the same level with Ba. Strontium can be