Question

The most widely accepted water quality criterion for measuring the organic pollution is

• A. Chloroform
• B. Ammonia
• C. BOD
• D. COD

Hint:

BOD value guide:
- \(1\text{--}2\text{ mg/L}\): Very clean water.
- \(3\text{--}5\text{ mg/L}\): Moderately clean water.
- \(>10\text{ mg/L}\): Highly polluted/sewage-contaminated water.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Organic pollution in aquatic systems results from sewage, agricultural runoff, and food processing wastes.
Evaluating this pollution requires measuring the oxygen demand exerted by the degradation of organic matter.

Step 2: Detailed Explanation:
Biochemical Oxygen Demand (BOD) is defined as the amount of dissolved oxygen required by aerobic microorganisms to biologically decompose organic matter present in a water sample over a specific period (typically 5 days at \(20^\circ\text{C}\)).
It is the most widely accepted and applied regulatory water quality criterion to determine the strength of organic waste and the level of organic pollution in water bodies.
Chemical Oxygen Demand (COD) measures all chemically oxidizable matter (both biodegradable and non-biodegradable), making BOD a more direct indicator of biological organic pollution.

Step 3: Final Answer:
The correct option is (C).