water pollution

Question 1

what is eutrophication? (simple definition)

Answer 1

• the process where nitrates and phosphates are added to water

Question 2

what are two causes of eutrophication?

Answer 2

• fertilisers
• sewage

Question 3

what is ‘leaching’?

Answer 3

fertiliser is applied and the it rains, causing runoff

Question 4

what is the toxic buildup of chemicals in predators at the top of food chains called?

Answer 4

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

Question 5

explain the process of eutrophication in steps

Answer 5

1. nitrates and phosphates are in fertilisers
   (also can happen in the context of sewage - nitrates are in faeces and phosphates in laundry detergent)
2. if too much fertiliser is applied, leaching can occur when it rains, which is where the extra nutrients are washed into water sources
3. 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.