Exchange Characteristics of Lead, Zinc, and Cadmium in Selected Tropical Soils

Table 3

Selectivity coefficient, 𝐾_𝑐, as a function of soil phase composition in Ca²⁺→M²⁺ exchange at 30°C and 60°C in the different soils studied.

(a) Selectivity coefficient, 𝐾_𝑐, for soil AD2

AD2
𝑋^′Cd	𝐾𝑐	𝑋^′Zn	𝐾𝑐	𝑋^′Pb	𝐾𝑐
30°C
0.00	0.00	0.00	0.00	0.00	0.00
0.30	33.05	0.43	5.54	0.46	0.67
0.43	50.89	0.61	14.49	0.69	1.05
0.71	19.62	0.77	10.08	0.83	1.24
0.86	10.30	0.91	4.14	0.93	1.35
1.00	0.00	1.00	0.00	1.00	0.00
60°C
0.00	0.00	0.00	0.00	0.00	0.00
0.32	23.06	0.42	5.72	0.46	0.65
0.42	44.26	0.57	17.88	0.68	2.03
0.73	12.84	0.76	9.60	0.83	1.67
0.87	7.20	0.91	3.77	0.92	2.21
1.00	0.00	1.00	0.00	1.00	0.00

(b) Selectivity coefficient, 𝐾_𝑐, for soil AD3

AD3
𝑋^′Cd	𝐾𝑐	𝑋^′Zn	𝐾𝑐	𝑋^′Pb	𝐾𝑐
30°C
0.00	0.00	0.00	0.00	0.00	0.00
0.18	127.48	0.40	13.37	0.43	7.57
0.24	196.05	0.62	15.83	0.61	19.80
0.31	219.09	0.76	14.44	0.77	13.70
0.73	41.83	0.88	10.82	0.89	10.75
1.00	0.00	1.00	0.00	1.00	0.00
60°C
0.00	0.00	0.00	0.00	0.00	0.00
0.14	356.00	0.38	24.53	0.45	2.56
0.31	241.90	0.58	33.68	0.64	9.30
0.55	112.83	0.73	28.50	0.75	17.58
0.79	44.30	0.88	13.12	0.90	7.22
1.00	0.00	1.00	0.00	1.00	0.00

(c) Selectivity coefficient, 𝐾_𝑐, for soil NB

NB
𝑋^′Cd	𝐾𝑐	𝑋^′Zn	𝐾𝑐	𝑋^′Pb	𝐾𝑐
30°C
0.00	0.00	0.00	0.00	0.00	0.00
0.34	24.06	0.42	6.03	0.46	0.18
0.48	39.50	0.65	7.23	0.69	0.53
0.68	24.71	0.79	7.65	0.83	1.03
0.88	8.50	0.92	2.64	0.93	1.00
1.00	0.00	1.00	0.00	1.00	0.00
60°C
0.00	0.00	0.00	0.00	0.00	0.00
0.36	17.64	0.41	8.44	0.46	0.13
0.51	28.85	0.61	12.84	0.69	1.78
0.72	16.82	0.75	11.84	0.83	1.39
0.88	7.22	0.91	3.68	0.93	1.23
1.00	0.00	1.00	0.00	1.00	0.00