Escherichia coli is used as an indicator organism to determine pollution of water with:

Options

A. Heavy metals
B. Faecal matter
C. Industrial effluents
D. Pollen of aquatic plants

Answer

**Step-by-Step Solution:**

1. **Understanding the Role of Escherichia coli (E. coli):**
- E. coli is a type of bacteria commonly found in the intestines of humans and animals. It serves as an important indicator organism in environmental studies, particularly in assessing water quality.

2. **Identifying the Context of Water Pollution:**
- The question is asking about the specific type of pollution that E. coli indicates when found in water. It is crucial to understand what E. coli signifies in terms of contamination.

3. **Analyzing the Options:**
- a. Heavy metals: E. coli is not an indicator of heavy metal contamination.
- b. Fecal material: E. coli is widely recognized as an indicator of fecal contamination in water.
- c. Industrial effluents: E. coli does not specifically indicate industrial pollution.
- d. Pollen of aquatic plants: E. coli is not related to pollen contamination.

4. **Conclusion:**
- Based on the analysis, the presence of E. coli in water samples is primarily used to indicate fecal contamination. Therefore, the correct answer is option **B. Fecal material**.

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