Drinking of mineral water with very low levels of pesticides (about 0.02 ppm) for long periods may:

Options

A. Produce immunity against mosquito
B. Cause leukemia ( blood cancer ) in most people
C. Cause cancer of the intestine
D. Lead to accumulation of pesticide residues in body fat .

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks what may happen if a person drinks mineral water containing very low levels of pesticides (0.02 ppm) over a long period.

2. **Identifying the Pesticide**: The most common pesticide associated with such scenarios is DDT (Dichloro-Diphenyl-Trichloroethane). It is known for its persistence in the environment and its tendency to accumulate in living organisms.

3. **Biomagnification Concept**: DDT exhibits biomagnification, which means that as you move up the food chain, the concentration of the pesticide increases in organisms. This is crucial to understand how even low levels of pesticides can lead to significant accumulation over time.

4. **Evaluating the Options**:
- **Option 1**: Produces immunity against mosquitoes. This is incorrect because pesticides do not confer immunity; they are toxic substances.
- **Option 2**: Causes leukemia or blood cancer in most people. This is also incorrect as the pesticide does not directly cause such cancers.
- **Option 3**: Causes cancer of the intestine. This is incorrect for similar reasons; the pesticide does not accumulate in the intestine.
- **Option 4**: Leads to accumulation of pesticide residues in body fat. This is correct as pesticides like DDT have a high affinity for fatty tissues and can accumulate there over time.

5. **Conclusion**: The correct answer is that drinking mineral water with very low levels of pesticides for long periods may lead to the accumulation of pesticide residues in body fat.