NATURAL AND MAN-INDUCED PHYTOREMEDIATION IN SEVERAL MINE RESIDUES CONTAINING HIGH CONCENTRATION OF CD - Management of Hazardous Residues Containing Cd - page 161

Table 2. Some soil characteristics of tailing samples

Site Color pH a Sand Silt Clay OM

b Total
Cd
mg kg -
1

c Cd-
DTPA
mg kg -1

San Antonio 1
Zimapan, Hgo

10YR3/6 d
5Y2.5/2

7.20.2 68 8 25  7 61.5 61.5 81464 100.2

5Y3/2 d
5Y2.5/2

San Antonio 2
Zimapan, Hgo

7.00.3 361.4 13 1 512 0.080.1 69951 170.13

Pal
Zimapan, Hgo

10YR4/6 d
2.5Y5/4

3.70.2 704.4 182.8 101.4 3.13 34038 5.90.2

San Francisco
Zimapan, Hgo

2.5Y5/3

7.20.2 437 27 3 3010 0.70.7 14154 3.20.2

Zacatecas
town
Zacatecas

10YR5/6 7.40.7 2910 135

585 4.31 23040 3.62.5

Sombrerete
Zacatecas

2.5YR4/2 7.10.3 5219 12 17 2610

3.42.3 83110 11.63

Fresnillo
Zacatecas

5YR3/2

8.40.3 829 12 5 64 1.233 3373 120.6

Noria de
Angeles
Zacatecas

2.5YR3/0 7.60.2 7421 10 2.6 1512 0.10.1

212.6 2.60.5

Temascaltepec
México

10YR4/4 5.71.2 940.7 4.50.7 0.50.7 2.65.1

2.80.2 0.320.3

a Average value plus standard deviation.
b Determined by Lin and Jackson (1982) procedure.
c Analyzed by Lindsay and Norvell (1978) procedure.
d Diferent tailings color was observed in these sites.

C D A CCUMULATION IN P LANT
T ISSUES G ROWING IN THE T AILINGS

In general, plant species growing naturally on tailing heaps avoid Cd
uptake, so Cd plant concentrations are low (Table 3), even when total Cd
concentration in media is high. Apparently they behave as Cd excluder plants.
The Cd plant concentration ranged from 1.5 to 39 mg kg -1 . Brickellia
veronicifolia , Euphorbia sp., Jatropha dioica , Polygonumn aviculare and
Teloxys graveolens were the species with high concentration of Cd in the