water pollution Flashcards
key words: eutrophication, leaching
1
Q
what is eutrophication? (simple definition)
A
- the process where nitrates and phosphates are added to water
2
Q
what are two causes of eutrophication?
A
- fertilisers
- sewage
3
Q
what is ‘leaching’?
A
fertiliser is applied and the it rains, causing runoff
4
Q
what is the toxic buildup of chemicals in predators at the top of food chains called?
A
bioaccumulation
—> caused by toxic substances being eaten or absorbed by their prey which eat each other, accumulating in the top predator… e.g. humans :0
eg pesticides, herbicides
5
Q
explain the process of eutrophication in steps
A
- nitrates and phosphates are in fertilisers
(also can happen in the context of sewage - nitrates are in faeces and phosphates in laundry detergent) - if too much fertiliser is applied, leaching can occur when it rains, which is where the extra nutrients are washed into water sources
- causes eutrophication;
- fertilisers enter the water, adding extra nutrients
- this increases the rate at which algae grow
- they begin to block the light from the sun
- plants can’t photosynthesise due to lack of light
- they begin to die
- microorganisms that feed on dead plants increase as their food source increases, using up more oxygen
- organisms that need oxygen e.g. fish, die.