Environmental Engineering Reference
In-Depth Information
a common historical practice for the upper Adriatic. Within the lagoon system 17 fish
rearing ponds (320 hectares in Marano) and 38 (1,088 hectares in Grado) are still active. Due
to the shallow depth of the basins, arise of temperature and salinity linked to hypoxia may
occur during summer periods, whereas occasionally frosts occur during winter.
On the other hand, the lagoon has been declared one of the polluted sites of national interest
(SIN; Ministerial Decree 468/01) because of its high level of sanitary and environmental risk
due to several factors. In this context one of the main concerns is represented by the high
concentration of mercury (Hg) in sediments and its related neurotoxicity whenever it is in
the food chain. SIN covers about 13,500 ha partially overlaps the SCI, and is actually subject
to environmental characterization, emergency safety measures, restoration, rehabilitation
plans and monitoring activity.
The Environmental Protection Agency of Friuli Venezia Giulia (ARPA FVG) is involved in a
monitoring network according to Directive 2000/60/CE (European Union, 2000), which is
applied in Italy following the Legislative Decree 152/2006. The WFD aiming to monitor and
solve the problems connected with quality of the water, to protect and to enhance the
restore of all the water bodies (inland surface waters, transitional waters, coastal waters and
ground waters in Europe). The final goal is to achieve a “good ecological and chemical
status” by the year 2015.
The data obtained represent an implementation of the past investigations (since the end of
the 80s) conducted by the Region FVG in a monitoring system of superficial water, where
physical, chemical and bacteriological data were recorded. GIS based analysis of data
collected from about 20 monitoring stations for the period 2000 - 2005 show that the lagoons
is characterized by a good diurnal oxygenation. On the other hand, a significant nutrient
supply pose a risk of distrophy close to river mouths with the induction of algal blooms and
possible oxygen falls during the night. Moreover, these areas are subject to high nitrogen
concentrations, which go beyond the limits stated into the Nitrate Directive.
4.2.1 Agriculture
Agriculture and breeding are activities connected to the quality of the Marano and Grado
Lagoon mainly through the related drainage basin of cultivated land. Rural economy of
Friuli Venezia Giulia is almost placed in the Lower Friulan Plan, where, during the last
century, 50,000 hectares of wetlands have been reclamed into cultivated areas. Nowadays,
70% of the agricultural land is arable and mostly planted with soybean, Indian corn,
beetroot and cereals (wheat and barley). There are also several vineyards or specialized fruit
farming.
The main risks posed by agricultural activities are pesticides and fungicides releases into the
lagoon system. The irrigation of the plantations, especially during the summer periods,
implies a serious water withdrawal, and the lack of vegetation enhances the problem of
erosion. In the considered territory, there are several breeding farming. The wastes of this
activity are used as fertiliser and, as a consequence, part is carried into the lagoon (Friuli
Venezia Giulia Region, 3
th
Interim Report “S.A.R.A. Regional System of Protected Areas”).
The main river courses of the area are loaded with the discharge of the channels belonging
to the agricultural drainage system. Thus, it results in a close relationship between
agriculture activities and the quality of waterways and lagoon ecosystem. The release of
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