Dissolved Oxygen (DO), a water quality parameter, is essential in which of the following water bodies/sources?

A) River Water
B) Lake Water
C) Tap Water
D) Underground Water
E) Pond Water

Choose the most appropriate answer from the options given below.

The correct option is A, B and E Only.

Detailed Explanation:
Dissolved Oxygen (DO) refers to the concentration of free, non-compound oxygen present in water. It is a crucial parameter for evaluating water quality due to its vital role in sustaining aquatic life.
Let us analyze the necessity of Dissolved Oxygen in each of the given water sources:
1. River Water (A), Lake Water (B), and Pond Water (E): These are natural surface water bodies that house active aquatic ecosystems. Dissolved oxygen is essential in these environments to support the respiration of fish, invertebrates, plants, and aerobic bacteria. A lack of sufficient DO in these water bodies leads to anaerobic conditions, causing harm to aquatic life and degrading the ecosystem.
2. Tap Water (C): Tap water is purified and treated for drinking and household purposes. Although dissolved oxygen can influence the taste of water and the rate of pipe corrosion, it is not a parameter that is essential for supporting biological habitats in this context.
3. Underground Water (D): Groundwater naturally has very low or virtually no dissolved oxygen. Because it is deep underground and sealed off from the atmosphere, aerobic biological activity depletion occurs without opportunities for re-aeration. Thus, DO is not a primary or essential parameter naturally maintained in underground aquifers to support typical aquatic ecosystems.
Consequently, Dissolved Oxygen is essential for River Water, Lake Water, and Pond Water.