Zusammenfassung der Ressource
Water Quality
- Drinking water needs to be good quality
- Essential for life, but must be free of poisonous
salts(eg. phosphates and nitrates) and harmful
micro-organisms - these can cause diseases such
as cholera and dysentery
- Most of our drinking water comes from reservoirs -
flows into reservoirs from rivers and groundwater -
water companies chose to build reservoirs where
theres a good supply of clean water
- Government agencies keep a close eye
on pollution in reservoirs, rivers and
groundwater
- To monitor water quality, water companies
take samples of water - from the water
entering the treatment works right through
to the taps in consumers' houses
- Some people still aren't satisfied - buy
filters that contain carbon or silver to
remove substances from their tap
water. Carbon in the filters removes
the chlorine taste and silver is
supposed to kill bugs. Can also buy
water softeners
- Totally pure water with nothing dissolved in it
can be produced by distillation - boiling water to
make steam and condensing the steam
- Adding Fluoride and chlorine to water has disadvantages
- Fluorine is added to drinking
water in some parts of the
country - reduces tooth decay,
chlorine prevents disease
- Some studies have linked adding
chlorine to water with an increase
in some cancers - chlorine can
react with some natural
substances and produce toxic
by-products - some think these
may cause cancer
- In high doses fluoride can cause
cancer and bone problems in humans -
some think it shouldn't be added to
drinking water - 'mass medicating' -
choose whether to have fluoride
toothpaste but not about tap water
- Levels of chemicals added
need to be carefully
monitored as too much could
be harmful