Question

There are two samples of water. Sample 1 has BOD 50 mg/lit and sample 2 has BOD 30 mg/lit. Then -
A. The degree of pollution is the same in both the samples
B. Sample 1 is more polluted than sample 2
C. Sample 2 is more polluted than sample 1
D. No inference can be drawn on the degree of pollution

Answer 1

Answer:

• The correct option is option B.) sample 2 is more polluted than sample 1.

Explanation:

• BOD is the Biological Oxygen Demand. It is defined as the amount of oxygen required by the microorganisms in the water to consume the organic matter dissolved in the water.

• It is often expressed in milligrams of oxygen per litre of water.

• So, if the BOD of a given water sample is very high, the number of microorganisms in it would also be very high, and the water would be more polluted and would not be used for domestic purposes.

• So, BOD levels are used to identify the pollution levels of the water.

• It is generally used in waste water treatment plants, so that the recycled water would not remain polluted and can be used for variety purposes.

• Also, the large amount of BOD levels significantly decreases the Dissolved Oxygen levels of the water, thereby affecting aquatic life because fishes and other aquatic animals cannot survive in such low levels of dissolved oxygen.

• Here, clearly sample 1 has high BOD than sample 2 therefore, sample 1 is more polluted than sample 2.