Thermal Pollution

Thermal pollution happens when the raise of temperature of a body of water (oceans, seas, lakes, etc.) resulted from human activities.

Cause:

• The discharge of hot water (from the effluents of industrial process + the cooling towers of electrical power stations) into nearby lakes and rivers.
• Excess heat cause the temperature of the water body to rise above normal value, which is between 5 and 10 Celsius. 

Effects:

• As the temperature increases, the solubility of oxygen in water decreases.
• Instant death of aquatic organisms which can only handle a specific amount of temperature.
• Food chain disturbed (by the death of those species), collapsing the ecosystem.
• Encourage the rapid growth of algae which leads to B.O.D. value to increase. 
• Permanent change in species composition of aquatic ecosystem

Ways to prevent:

• Control the discharge of water into 

1. Surrounding lakes and rivers
2. still/slow-moving rivers

• effluents: liquid waste or sewage discharged into a river or the sea. 
• B.O.D.: acronyms of Biochemical Oxygen Demand, referring to the amount of oxygen used when all of the organic matter in 1 litre of water is oxidised by living organisms in the water.

References

Gan Wan Yeat. Success Biology SPM. Shah Alam : Oxfard Fajar Sdn. Bhd.

Page 302