Presentation elaborated by student's of Liceo Basile

1. Water
pollution

2. Water is undoubtedly the most widespread and common substance diffused
in the environment and is one of the most important. In addition to being
used as a source of life for plants and animals, it is used in factories and
industries .Water can perform its functions only if it flows continuously.
This performance is called “the water cycle”. Water can reach the sea not
only through rivers but also flowing from the ground, after being infiltrated
and having reached a shallow aquifer. One can easily guess that water can
be contaminated not only through rivers but also through soil pollutants. An
important cause of water pollution derives from the discharges of the
organic material. The decomposition of organic substances consumes the
oxygen in the water , sometimes up to slay the river fish. The main sources
of organic pollution are: the city sewers , farms , industries and agriculture.

6. The city sewers:
the sewages which are found in the sewers contain large amounts of human
excrements , so they should go through treatment plants before being
discharged into rivers. Unfortunately in Italy less than half of the
discharges are purified. The sewage can contain microorganisms which
cause some diseases such as cholera, salmonellosis etc. People are likely to
get sick if they ingest these organisms (it can happen while taking a bath in
the river or eat contaminated shellfish). Farms wash away the excrements,
the sewage are partially used as fertilizers and partially discharged into
rivers. Some types of industries, for example food industries, download
organic materials directly into rivers. As far it regards agricolture
fertilizers, both chemical and natural, they can pollute rivers.

10. Sources of pollution:
Direct land based sources: urban-domestic-industrial waste waters, rain
water that have collected on the ground polluting materials
Indirect land based sources: they are represented by the pollutants carried
by rivers and during the transport have undergone a certain dilution.
Atmospheric sources: for the fallout of radioactive substances due to land-
based activities such as thermal and nuclear power plants.

14. But there aren’t only the negative
aspects…. The state has created
laws for the protection of the sea
and also the reserves

17. The end
Simona , Giorgia, Maria Grazia,
Beatrice e Paola!