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

(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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