thermal pollution

Question 1

what is the source of thermal pollution

Answer 1

• the main source is the hot water in steam turbine power stations that use cold water from water bodies to condense the steam
• the coolant is returned to the source at an increased temp
• incomplete combustion of hydrocarbons

Question 2

what are the effects of thermal pollution

Answer 2

1) dissolved oxygen decrease

2) decreased aquatic organsims

Question 3

outline why dissolved oxygen is affected by thermal pollution

Answer 3

1) the maximum amount of oxygen that can dissolve in water is controlled by oxygen
2) as temperature increases the volume of oxygen which can be dissolved into a water body decreases causing deoxygenation of water

Question 4

what are the biological affects of thermal pollution

Answer 4

1) high temps may cause denaturation of proteins
2) decreased populations
3) increased temps cause increased respiration- there isn’t enough oxygen so aerobic organisms die
4) organisms pushed out range of tolerance

Question 5

what are the physiological changes which high water temps can cause

Answer 5

1) increased metabolic rates so more energy is used leaving less for growth
2 )increased development of eggs so they hatch earlier
3) colonisation of new species which outcompete old
4) resistance to disease is reduced

Question 6

how can thermal pollution be controlled

Answer 6

1) cooling towers

Question 7

outline how cooling towers can decrease thermal pollution

Answer 7

1) used to reduce thermal pollution by dispersing heat into the atmosphere
2) hot water is sprayed from a shower floor in the lower part of a tall hollow tower
3) the air in the tower absorbs heat from the water and rises up the tower
4) the air escapes into the open atmosphere
5) creates an updraught which draws more air through the tower spray
6) now cooled water is returned