Pollution

• Chemical waste and sewage in rivers results in water not being drinkable and eutrophication can occur
• Sulphur dioxide dissolves in rain, causing acid rain which increases acidity of lakes and leaches aluminium out of the soil
• Acid rain leads to:

  • Damage to fishes’ gills. Fixed by adding calcium hydroxide (slaked lime)
  • Destroys top of trees and aluminium damages tree roots, important nutrients leached away
  • SO2 poses health hazards for humans (asthma sufferers)
  • Damages limestone buildings and sculptures
  • Fewer crops can be grown on an acidic field (fixed by adding lime)
• Insecticides (kill insects): meant to kill insects which eat crops, but can kill other, useful insects such as bees which are pollinators, or by bioaccumulation (the increase in dose of toxin from one level of the food chain to the next)
• Herbicides (kill weeds): can be harmful to animals which eat the plants
• Nuclear fall-out:

  • Radioactive particles are sprayed into the atmosphere in a nuclear accident or bombing;
  • These particle “rain” back to earth from clouds, sometimes far from the accident site;
  • The radioactivity damages DNA and causes cancer and radiation illness at every level of the food chain.
• Non-biodegradable plastics:

  • Choke birds, fish and other animals
  • Fill up the animals’ stomachs so that they can’t eat food
  • Collect in rivers, and get in the way of fish
• Acid rain:

  • Caused by sulphur dioxide (burning fossil fuels) and nitrogen oxides (nitrogen reacting hot engines), as they dissolve and cause acid rain
  • Damages trees and plants, and kills fish and other river life
  • Prevention: catalytic converters in cars, in factories slaked lime neutralizes these acidic oxides and use of flue-gas desulfurization
• Global Warming:

  • Increase in Earth's average temperature
  • Started as we began burning fossil fuels
  • Scientists believe fossil fuels are the cause – not proven yet
  • Increase in carbon dioxide and methane concentrations in atmosphere cause enhanced greenhouse effect, leads to climate change
• Negative impact of female contraceptive hormones in water causes:

  • Reduced sperm count in men and feminisation of aquatic organisms
• Eutrophication: when water plants receive too many nutrients.

  
• Eutrophication:

  • Fertilisers put in soil
  • Fertilisers with nitrates / detergents with phosphates leach into rivers & lakes after rain
  • Water plants grow more than usual
  • They block sunlight and kill plants underneath
  • Bacteria/fungi decompose remains using the O2 and decreasing the O2 concentration
  • Fish and other creatures die from oxygen starvation