Agriculture Reference
In-Depth Information
Pb
1.00
Cd
1.00
0.75
0.75
0.50
0.50
0.25
0.25
0.00
0.00
0
200
400
600
800
1000
0
200
400
600
800
1000
Leaching time (h)
Leaching time (h)
Cr(VI)
As(
V
)
1.00
1.00
0.75
0.75
0.50
0.50
0.25
0.25
0.00
0.00
0
20
40
60
80
0
200
400
600
800
1000
Leaching time (h)
Leaching time (h)
0.5
a -BHC
0.4
0.3
0.2
0.1
0.0
0
200
400
600
800
1000
Leaching time (h)
Figure 3. The experimental data and predicted breakthrough curves obtained according
to the Yoon-Nelson model for Pb, Cd, Cr(VI), As(V) and ʱ-BHC leaching in soil A.
However, organochlorine pesticides had been prohibited to use by the
state and residual organochlorine pesticides in soil could be adsorbed and
biodegraded gradually, which reduced the risk of organochlorine pesticides to
agricultural production and groundwater system.
The relative concentrations of of Pb, Cd, Cr and As chemical fractions in
soil A before and after column leaching tests are listed in Table 4. As the
results show in Table 4, there were some variations in the proportions of five
fractions for the four elements after column leaching tests. The relative
concentrations of other four fractions of the elements except residues were all
