Step 1: Understanding the Question:
The question asks for a typical Biochemical Oxygen Demand (\(BOD\)) value for water that is considered "highly polluted."
\(BOD\) is a measure of the amount of dissolved oxygen needed by aerobic biological organisms to break down organic material in a given water sample.
Step 2: Detailed Explanation:
Significance of \(BOD\):
\(BOD\) is used as an indicator of the organic pollution level of a water body. High organic matter (from sewage, industrial waste, etc.) leads to high bacterial activity, which consumes more oxygen.
Classification of Water Quality based on \(BOD\):
1. Pure/Clean Water: \(BOD\) value is usually less than \(1\) ppm.
2. Moderately Clean Water: \(BOD\) ranges between \(1\) and \(5\) ppm.
3. Polluted Water: \(BOD\) values above \(5\) ppm indicate significant pollution.
4. Highly Polluted Water: When \(BOD\) values exceed \(10\)-\(15\) ppm, the water is considered very dirty or highly polluted. Such water has low dissolved oxygen, making it difficult for fish and other aquatic life to survive.
Interpreting the Options:
- \(8\) ppm and \(10\) ppm indicate pollution but are on the lower end of the "highly polluted" spectrum.
- \(12\) ppm is significantly polluted.
- \(17\) ppm (and above) represents a high concentration of organic waste, typical of untreated sewage or industrial effluents, fitting the description of "highly polluted" water best among the choices.
Step 3: Final Answer:
The \(BOD\) of highly polluted water is typically around 17 ppm or higher.