The pollution in the Lagoon of Venice EarthCache
The pollution in the Lagoon of Venice
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[ENG]: An earthcache to know the contamination of the Lagoon
of Venice
[ITA]: Una earthcache per conoscere lo stato
dell'inquinamento della Laguna di Venezia
Image from Wikipedia:
http://it.wikipedia.org/wiki/File:Venice_Lagoon_December_9_2001.jpg
[ENG]: Coastal lagoons occupy more than 10% of coastal areas
worldwide. The Lagoon of Venice is the largest lagoon in Italy and
one of the largest in Europe and Mediterranean region. It is
located in the north-eastern part of the Italian peninsula, between
the Adriatic Sea and the Po Valley (approx 45.2°-45.6°N,
12.2°-12.6°E). It is a complex ecosystem, affected by natural
factors and several centuries of heavy human influence. The lagoon
covers an area of about 550 km2 of which 5% is deeper
than 5 meters and 75% shallower than 2 meters; the average depth is
1.2 meters. This lagoon is connected to the sea by three narrow
inlets and it exchanges both waters and sediments following the
tidal cycle.
Today, the Lagoon of Venice appears as a shallow transitional
environment composed by a complex combination of intertidal marshes
(barene), mudflats (paludi), submerged mudflats (velme) and
channels (canali). As a part of a transitional environment, the
Lagoon of Venice is naturally forced to become sea or land, and its
equilibrium is permanently unstable. This is the cause of its great
changes in the past centuries, and the natural destiny of this
transitional environment will be to evolving either into a marine
bay or, through a salt-marsh environment, into a dry land. These
could be the fates of the Lagoon of Venice without the human
intervention to decrease the natural processes of erosion or
deposition of sediments. Only because of this uninterrupted work by
the Republic of Venice and Italy, the lagoon has maintained its
form through the last centuries.
This way, the Lagoon of Venice is one of the most studied
ecosystems in the world, because the natural processes have been
greatly influenced by human activities since 900 AD, which have
historically controlled the balance between sedimentation and
erosion in order to prevent its filling-up and transformation into
a marsh. In particular, in the last decades the Lagoon of Venice
have received increasing attention from the physical, chemical,
biological, geological and ecological point of view from local and
national authorities (University of Venice, Italian National
Research Council) and international associations (UNESCO). At the
present time, the increasing occurrence of extreme flooding events
in the lagoon (commonly called as ‘‘acqua
alta’’) is the most worrying problem of Venice,
magnified by the consequent problems of degradation of the town and
their artworks.
However, another important problem concerning the Lagoon of Venice
is their environmental pollution. The entire area has a long
history of heavy industrial activity occurred mainly after the
World War II, with the construction of the industrial area of Porto
Marghera, almost 12 km2-wide, hosting chloro-soda
processes, coal power plants, oil refining , metallurgical and
several other chemical production plants. Moreover, the emissions
of the artistic glass factories of islands of Murano, the shipping
traffic, the presence of rivers, streams, land runoff, the urban
wastes and the atmospheric depositions can contribute significantly
to the pollution of the lagoon. For these reasons, the pollution of
the lagoon comprises the contamination of sediments, water, air and
organisms. In late XIX century, Venice had not an industrial center
and had not a port able to compete with other cities in the
Mediterranean basin. The main problem was the lack of a suitable
place for this purpose. The problem was solved in 1907 with a law
on ports and in 1917 with the founding of the Society of Porto
Industriale di Venezia, which performs operations that led to the
creation of the first plants of Porto Marghera. The first
industrial center was built near the present Fincantieri. During
the World War II the port became a sensitive target for the Allies.
The industrial zone was bombed several times, blocking their
activity and involving also the inhabitants of neighboring
villages. After the war there was only rubbles. Production resumed
only since the 1950s, when Porto Marghera began to be one of the
most important industrial centers of Italy. The industrial zone of
Porto Marghera reached the maximum expansion in the 1960s and today
suffers a great economical chrisis. This earthcache is located in
the island of Tronchetto.
From the cache coordinates you will see the central part of the
Lagoon of Venice, between the Venice city center and the industrial
zone of Porto Marghera. This is considered the most polluted area
of the lagoon because historically affected by the most severe
anthropogenic pressure. Here, the main contamination affects both
the sediments and the organisms living in the sediments, such as
mussels and clams. For longtime wastes have been discharged from
the plants of Porto Marghera into the surroundings canals, and, in
the other hand, urban wastes has been released from the historical
center of Venice directly into the lagoon. The relative fine
grain-size of sediments and the relative low water circulation
contribute significantly to the accumulation of the pollutants in
this area. Most recent studies highlights the worrying
environmental status of the Lagoon of Venice, affected by high
levels of many metals (e.g., zinc, cadmium, lead, copper, cobalt,
and mercury) and several persistent organic pollutants (POPs), such
as dioxins, chlorinated pesticides, polychlorobiphenyls (PCBs),
polycyclic aromatic hydrocarbons (PAHs). In the last decades, the
Dept. Environmental Sciences of the Univerity Ca’ Foscari of
Venice has give a great impulse to the study of the pollution of
the lagoon.
Earthcaches are often located in very spectacular places from the
geological, historical and environmental point of view. However,
sometimes a cache can also be put in a place not spectacular to
see, but a place that has to think of the relationship between man
and nature. This is that! To log this cache you must go at the
coordinates, and you must answer at four questions:
1) What is the extension (in km2) of the industrial zone
of Porto Maghera?
2) What is the main pollutants affecting this area of the Lagoon of
Venice?
3) Try to count the number of industrial chimneys you can see in
the industrial zone.
4) The lagoon is subject to the tidal cycle. Try to search (and
explain) the most visible effect of the tide in the area (e.g., see
on the shore between lagoon and land).
Send me the correct answers using my geocaching mail. If you want,
you can make a photo of you and your GPS device in the earthcache
site! Logs without correct answers will be extinguished regularly.
Good earthcaching!
Additional Hints
(Decrypt)
N yvggyr uvag ol zunkk: Qb lbh xabj gung "Vfbyn qry Gebapurggb" vf nyfb xabja nf "Vfbyn ahbin"?