ICSE Class 9 Answered

Effects of water pollution are:

• When phosphorus and nitrates from fertilisers are disposed in water bodies, they promote the growth of algae. The presence of algae in water bodies in large number reduces the amount of dissolved oxygen in water resulting in the death of fishes and other water organisms.

• Industrial effluents include chemicals like mercury, lead, cadmium etc. These chemicals, when they reach the human body through the consumption of fishes, may cause irritation, insomnia, nervous disorder and may also affect the brain.

• Thermal pollution increases the temperature of water which in turn reduces the level of oxygen in water. This results in the death of many species of fishes.

• Oil drills and oil spills contaminate sea water which leads to the death of marine organisms.