Formative Practice 3.2 – Form 5 Science (KSSM) Chapter 3

Question 1:
Name three types of environmental pollution.

Land pollution, water pollution, air pollution, thermal pollution
(any three)

Question 2:
(a) What is eutrophication?
(b) Name the type of pollution related to eutrophication.

Eutrophication is the response of the ecosystem towards the addition of phosphate and nitrate ions (from detergents, fertilisers and rubbish) into an aquatic ecosystem.

Water pollution

Question 3:
Name one type of pollution which causes the following harmful effects:
(a) greenhouse effect and global warming
(b) climate change

(a) Air pollution

(b) Air pollution, thermal pollution

Question 4:
(a) What is Biochemical Oxygen Demand (BOD)?

(b) What is the relationship between BOD and the level of water pollution in a water sample?

Biochemical Oxygen Demand (BOD) is the amount of dissolved oxygen needed by microorganisms such as bacteria to decompose organic substances.

The higher the BOD of a water sample, the higher the level of pollution of the water sample.

Question 5:
How does methylene blue solution function as an indicator of the water pollution level in a water sample?

The time taken for methylene blue solution to decolourise in a water sample determines the level of pollution in the sample. The shorter the time taken for the methylene blue solution to decolourise, the higher the level of water pollution of the sample.

Question 6:
(a) Name the microorganisms used to make effective microorganism mud balls (EM mud balls).

(b) How do effective microorganisms treat polluted water?

Effective microorganisms comprise three types of microorganisms namely:
• Lactic acid bacteria such as Lactobacillus casei
• Photosynthetic bacteria such as Rhodopseudomonas palustris
• Yeast (Saccharomyces cerevisiae)

Effective microorganisms treat polluted water as follows:
• treat sewage
• eliminate foul odour in water
• stunt growth of dangerous microorganisms
• increase dissolved oxygen
• reduce BOD
• facilitate the decay of organic substances to produce substances needed for the growth of green plants

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