Spraying the pesticide DDT on agricultural crops mainly causes pollution of which environmental components?

Introduction / Context:
This question examines your understanding of environmental pollution, specifically the impact of using persistent chemical pesticides such as DDT (dichloro diphenyl trichloroethane) on agricultural fields. DDT is a classic example of a persistent organic pollutant, and knowing where it accumulates in the environment is important for questions related to ecology, pollution, and public health. The focus is on identifying which components of the environment are most affected when DDT is sprayed on crops.

Given Data / Assumptions:

• DDT is a synthetic chemical pesticide used for pest control in agriculture and for vector control in public health.
• It is highly persistent, meaning it does not break down quickly.
• The question asks which components of the environment are polluted due to spraying DDT on crops.
• Options include combinations of air, soil, water, and crops.

Concept / Approach:
When pesticides like DDT are sprayed on fields, part of the spray may temporarily be present in the air as fine droplets, but the main environmental issue is long term contamination. DDT settles onto the soil surface and also reaches water bodies through runoff and leaching. Because it is fat soluble and non biodegradable, it accumulates in the soil and aquatic ecosystems, leading to bioaccumulation and biomagnification in food chains. Therefore, we focus on those environmental components where DDT persists rather than just where it briefly passes through.

Step-by-Step Solution:
Step 1: Recognize that after spraying, DDT droplets eventually fall on the soil surface around crops.Step 2: Due to rain and irrigation, DDT can be washed from the soil into nearby ponds, rivers, or groundwater, leading to contamination of water.Step 3: DDT is not very volatile compared to some other chemicals, so long term air pollution is not the major concern, although there can be a short lived presence in the air while spraying.Step 4: Because of its persistence, the most significant and long lasting pollution occurs in soil and water.Step 5: Therefore, among the given options, the combination that best represents the major polluted components is soil and water.

Verification / Alternative check:
Standard environmental science textbooks emphasize that DDT accumulates in soil and aquatic systems and then moves into organisms such as plankton, fish, and birds. This is why issues like thinning of eggshells in birds of prey became famous examples of DDT related damage. If air pollution were the main issue, we would talk more about gaseous emissions and inhalation effects, which is not the case with DDT. This confirms that the key environmental targets of DDT are soil and water bodies.

Why Other Options Are Wrong:
Air and soil: This ignores the important contamination of water, where DDT bioaccumulates and affects aquatic food chains.
Crops and air: Crops may have residues, but air is not the main long term sink, and water is missing from this option.
Air and water: Again, soil is missing, although soil is a primary sink for DDT in agricultural ecosystems. Thus these combinations are incomplete or emphasize the wrong components.

Common Pitfalls:
Students may focus only on the immediate spraying process and think mainly about air, since spray droplets are airborne for a short time. This leads to overemphasis on air pollution. Another confusion is between residue on crops and environmental sinks. While DDT residues on crops matter for food safety, the question is asking about environmental pollution, which is dominated by soil and water contamination. Careful reading and understanding of the long term fate of DDT avoids these errors.

Final Answer:
Spraying DDT on crops mainly causes pollution of soil and water.