(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)
■Agrochemical from neighboring farms causes eutrophication e.g. pesticides
-Poison the fish and plants life (living organism)

■Siltation – reduce photosynthesis
               - clog gills of fish
               - causes turbidity

■Industrial wastes e.g lead, mercury (heavy metals) get fixed in the food chain that gets its way to man.

■Untreated sewage – causes eutrophication
 - reduce oxygen in water.
-causes decomoosition
-causes diseases
 -increases turbidity reducing light penetration

■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
 -reduces concentration of oxygen.

         b)-proper sanitation
 -proper hygiene
 -boiling drinking water
 -avoid coming into contact with water bare footed
 -draining stagnant water
 -washing fruits with clean water
 -proper cooking of food
 -destroying the vectors
 -proper storage of food / cover food  2mks

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