Groundwater In Depth

Question 1

How is the rate of movement of nitrate influenced?

Answer 1

influenced by the depth of the water table (the thickness of the unsaturated zone) and by nature of aquifer where fractured rocks allow fast movement and chalk/sandstone allow slow movement.

Question 2

How does rainfall alter nitrate concentrations?

Answer 2

High rainfall dilutes the nitrate concentration in groundwater, little rain increases conc - evident in dry areas of UK such as SE.

Question 3

How can you reduce Nitrate pollution in groundwater?

Answer 3

Reduce at source: - reduce the use of artificial fertilisers

• reduce the extent of ploughing in the autumn
• sow autumn crops early
• avoid bare grounds in the winter (cover crops)
• carefully manage the disposal of farm waste

Question 4

What health risks does nitrate pose ?

Answer 4

Blue baby syndrome in infants

bacteria may convert nitrate into carcinogens in digestive tract.

Question 5

What controls the fate and behaviour of pesticides?

Answer 5

extent of their uptake by crops and their susceptibility to leaching and degradation along with absorption onto soils.

Question 6

What effects does dissolution have on a petrochemical spill?

Answer 6

Causes a single spill to spread out over a large area contaminating a greater area of groundwater etc

Question 7

what are the remedies to removing groundwater pollution?

Answer 7

most remedies are essentially ineffective due to time scales and costs however what can be done includes:

• determine which zone the contaminant is in and whether it is in solution of non aqueous forms
• containment of pollutant by physical barriers
• removal of contaminant by pumping then treating
• removal of volatile gas fractions
• bioremediation encouraging bacterial growth to promote degradation of POPs