Page 412 - Soil and water contamination, 2nd edition

Answers to exercises 399

CHAPTER 10
4. a. 10 days
b. 20 kg
c. 10 days

8. a. 1 dimension: P transport in soil is mainly in the vertical plane;
b. 2 dimensions: at least the lateral interaction should be considered;
c. 0 dimensions may be sufficient; to account for vertical variations in pesticide
concentrations or soil organisms in the soil profile, a one-dimensional model may be
required.

CHAPTER 11
1. 0.346 tonnes y -1

3. 2500 s

4. 40 mg l -1
2 -1
5. a. 0.01 m d
b. longitudinal dispersion;
c. 5.15 mg l -1
d. 5.15 mg l -1
e. The effects of reduced flow velocity are nullified by the extra time required for
dispersion;
f. The dispersion in porous media is due to variations in flow velocities and flow paths
within the medium. Thus, dispersion is proportional to the distance travelled.

6. a.

Concentration

6642 6642 6642
0 0.75
Distance (m)

b. 4.07 mg l -1
c.

Concentration

6955
0 1 1 / 3
Time (d)

10/1/2013 6:47:53 PM
Soil and Water.indd 411 10/1/2013 6:47:53 PM
Soil and Water.indd 411