Question

A pond containing clean water after 1 year had a decreased level of oxygen .Which of the following activities is not a possible reason?

• A. Washing clothes in the pond.
• B. Release of industrial effluents
• C. Washing motor vehicles in the pond.
• D. Swimming in the pond.

Answer 1

The correct option is D

Swimming in the pond.

Swimming doesn't add any nutrients to waterbody and hence produce the least pollution of water. Washing clothes in the pond, release of industrial effluents, washing motor vehicles in the pond will produce lots of dirt and adds various nutrients from soaps and detergents. Nutrients from fertilizers and pesticides also gets accumulated to cause algal bloom which in turn reduces the oxygen level of water, all leading to the death of water causing eutrophication.