(A) DESCRIBE CAUSES AND EFFECTS OF WATER POLLUTION. (10MKS) (B) DESCRIBE THE VARIOUS CONTROL MEASURES FOR WATER BORNE DISEASES (10MKS)

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(a) Describe causes and effects of water pollution. (10 mks)
Agrochemical from neighboring farms
  • causes eutrophication e.g. pesticides
  • poison the fish and plants life (living organism)
Siltation
  • reduce photosynthesis
  • clog gills of fish
  • increases turbidity
Industrial wastes e.g lead, mercury (heavy metals) hence poisoning
  • heavy metals fixed in the food chain that gets its way to living things and to man.
Untreated sewage –
  • causes eutrophication
  •  reduce oxygen in water
  • causes decomposition
  • causes diseases
  • increases turbidity reducing light penetration
  • increases biochemical oxygen demand
Spilt oil from tankers or used oil from garage
  • limits supply of oxygen to aquatic life
  • covers stomata of plants
  • clogging gills and feathers of bird
hot water
  • kills organism
  • affects enzymatic reactions in organisms
(b) Describe the various control measures for water borne diseases (10 mks)
  • proper sanitation
  • proper hygiene
  • boiling drinking water
  • chemical treatment of drinking water
  • avoid coming into contact with water in runoffs, pools, bogs and ponds bare footed
  • draining stagnant water
  • washing fruits with clean water
  • proper cooking of food
  • destroying the vectors
  • proper storage of food/cover food 
 (2 mks per point)

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