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

Options

A. industrial effluents
B. heavy metals
C. pollen of aquatic plants
D. (iii) line source, fixed source (iv) Eichhornia, tiger of Bengal

Explanation

**Step-by-Step Solution:**

1. **Understanding Escherichia coli (E. coli):**
- E. coli is a type of bacteria that is commonly found in the intestines of humans and animals. It is part of the coliform group of bacteria.

2. **Role of E. coli as an Indicator Organism:**
- E. coli is used as an indicator organism to assess the quality of water. Its presence in water suggests contamination.

3. **Identifying the Source of Contamination:**
- The primary source of E. coli in water is fecal matter. When water is contaminated with fecal matter, E. coli can be present, indicating potential health risks.

4. **Analyzing the Options:**
- The options given are:
1. Industrial effluents
2. Heavy metals
3. Pollen of aquatic plants
4. Fecal matter
- Among these options, only fecal matter is directly associated with the presence of E. coli.

5. **Conclusion:**
- Therefore, E. coli is used as an indicator organism to determine pollution of water with fecal matter.

**Final Answer:**
Escherichia coli is used as an indicator organism to determine pollution of water with fecal matter.

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