MAP Technical Reports Series No. 106 UNEP

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Mapping of this sort could be made more meaningful if adjusted for levels of sewage
treatment installed and pollution abatement measures taken generally. These, and progressive
completion of water quality assessment of coastal waters could serve for a long-term evaluation
of likely pollution trends. Of course, the primary goal must remain the complete inventory and
assessment of all sources that contribute to coastal eutrophication, and its abatement.
b) Estimation of Nitrogen and Phosphorus discharged to the Mediterranean Sea
i) The Italian Pilot Studies. Chiaudani et al. (1978) in their extended investigation on
eutrophication related subjects have compiled extended statistics on population, industries,
fertilizers used in agriculture, and animal husbandry in Italy, and calculated source strength and
emission of phosphorus for each category, region by region, and by hydrographic basins. The
authors conclude that the total phosphorus emission from all sources would amount to 59,000
t/year (1974-76 data), of which 42% alone are generated by the four Northern Adriatic Sea bound
Regions: Piemonte, Lombardia, Emilia-Romagna, Veneto.
Further, the estimated totals per category and percent distribution of phosphorus
emission by category is reported as following:
1000 t/year %
a) Domestic Detergents
19.60
Metabolic
16.24 60.65
b) Agriculture 10.52 17.80
c) Livestock Cattle
Hogs
Sheep and Goats
Horses
Poultry
Total livestock
3.88
2.50
0.69
0.32
0.49
7.88 13.35
d) Industries 3.58 6.06
e) Uncultivated Lands 1.27 2.14
Total 59.09
In principle, this distribution is still valid except for household detergents, the use of
which has been restricted by law to 2.5% since 1986, and to 1% as of March 1988. Marchetti
(1987) has re-evaluated the earlier estimates on the basis of new data taking into account the
reduction of polyphosphates in detergents and assuming a retention coefficient of 50% of
phosphorus from the domestic environment. In addition, he has extended the estimates to
include nitrogen assuming that 3% of the phosphorus fertilizers and 20% of the nitrogen
fertilizers is exported to waterways. As regards phosphorus and nitrogen from animal
husbandry, he assumes an export coefficient of 5% of the quantities produced by category.
Accordingly, the new estimates read as following:
1000 t/year %
a)
Phosphorus
Domestic Detergents
Metabolic
Total
6.21
16.39
22.60 46.36
b) Agriculture Cultivated lands 14.42 29.58