Which of the following statements about soil pollution is INCORRECT?
- AStoring surplus rainwater by constructing bunds, ponds, etc. belongs to the category of area treatment method.
- BIn temperate regions, DDT has a half-life of 10-15 years.
- CIrrigation water can cause salinisation of soil.
- DThe area treatment method to prevent soil erosion involves treating the natural water courses.Correct
Solution
Concept
Area treatment treats the catchment land surface. Drainage line treatment treats natural water courses.
Step-by-step solution
1. Soil erosion control has two methods: area treatment and drainage line treatment. 2. Area treatment works on the land surface. Examples are bunds, ponds, terracing and afforestation that store surplus rainwater. 3. Drainage line treatment works on natural water courses (gullies, nallas), for example check dams and gully plugs. 4. Statement D says area treatment treats natural water courses, so D is wrong. 5. DDT is persistent, with a half-life of about 10-15 years in temperate soils, so B is correct. 6. Irrigation water with poor drainage leaves salts in the soil, so C is correct. 7. The INCORRECT statement is (D).
Explanation
In area treatment we treat the land of the catchment, for example with bunds and ponds that store rainwater. Treating natural water courses is called drainage line treatment, not area treatment. So statement D is incorrect.
Why the other options are wrong
A: Correct. Bunds and ponds that store surplus rainwater are area treatment measures. B: Correct. DDT persists in temperate soils with a half-life of about 10-15 years. C: Correct. Irrigation water can bring and leave salts, causing salinisation.
Shortcut
Area = land surface. Drainage line = water courses.
Common mistake
Mixing up area treatment with drainage line treatment.
Correct answer: D) The area treatment method to prevent soil erosion involves treating the natural water courses.