Desalination of water and fluoridation

Desalination of sea water

• desalination is the removal of salt from sea water. it is a method of obtaining additional drinking water to meet the demand

• Distillation is the simplest method of desalination, other methods incluse the use of memebrane systems (reverse osmosis)

Describe distillation

seawater is heated causing pure water to evaporate into a gas and rise, to be collected in the condenser. The water vapour then condenses back into a liquid and drips out forming pure water able to be drunk.

What does the method of desalination depend on?

• closeness to the sea

• availability of ‘clean’ energy supplies

• country’s wealth

Fluoridation

process where fluoride is added to water to prevent tooth decay, different areas of the UK have different amounts of fluoride added to the water; Welsh water has no fluoride. There is a debate on the fluoridation of water.

advantages of fluoridation

• strengthens tooth enamel

• reduces plaque acid

• better oral hygiene

• less visits to the dentist

• less dental fillings

• less tooth extractions

disadvantages of fluoridation

• fluorosis (discolours teeth)

• stomach and bone cancer

• unethical and immoral to force people to drink fluoridated water

• infertility in males

• seen as a mass medication

• high concentrations is poisonous