Question

A water sample shows high COD but relatively low BOD. This indicates the presence of

• A. Easily biodegradable organic matter
• B. Non-biodegradable organic pollutants
• C. Inorganic salts only
• D. Pathogenic microorganisms

Hint:

Remember: \[ \boxed{ \begin{aligned} \text{High BOD} &\rightarrow \text{Biodegradable organics} \text{High COD with low BOD} &\rightarrow \text{Non-biodegradable organics} \end{aligned} } \]

Answer 1

The Correct Option is B

COD measures the oxygen required to oxidize both biodegradable and non-biodegradable organic matter, whereas BOD measures only the oxygen required by microorganisms to decompose biodegradable matter. Therefore, a high COD with relatively low BOD indicates the presence of non-biodegradable organic pollutants. Hence, \[ \boxed{\text{Non-biodegradable organic pollutants}} \] is the correct answer. Therefore, \[ \boxed{(B)} \]