Question

Explain how pH change in the lake water can endanger the lives of aquatic animals (like fish). What can be done to lessen the danger to the lives of aquatic animals in the lake?

Answer 1

Because of acid rain (when the pH of rainwater is 5.6), the acidity of river and lake water increases. Aquatic animals find it very difficult to survive in water with low pH levels, and they die.
To neutralise this excess acidity in lakes and rivers caused by acid rain, calcium carbonate, a base, is frequently mixed with the water.