MAP Technical Reports Series No. 106 UNEP

- 43 -
c) Livestock Cattle
Hogs
Sheep and Goats
Horses
Poultry
Total Livestock
3.15
1.71
0.36
0.22
1.45
6.88 14.11
d) Industries 3.60 7.39
e) Uncultivated Lands 1.25 2.56
Total 48.75 t/year
Nitrogen:
1000 t/year %
a) Domestic Metabolic 127.13 19.31
b) Agriculture Cultivated lands 420.00 63.80
c) Livestock Cattle
23.29
Hogs
5.09
Sheep and Goats
2.21
Horses
1.55
Poultry
4.08
Total Livestock
36.21 5.50
d) Industries 50.00 7.59
e) Uncultivated Lands 25.00 3.80
Total 658.340 t/year
Accordingly, the total phosphorus load would amount to approximately 49,000, and that
of nitrogen to about 660,000 t/year. The latter is about 20% higher than Provini's et al. estimate
of 540,000 t/y (Provini et al., 1979).
Comparison between these estimates shows the difficulty in estimating total loads.
Although the main difference regarding phosphorus is due to the assumed reduction in
polyphosphate and retention in treatment plants and septic tank disposal, the respective
estimates are of the same order of magnitude, despite the variation in the single component
data. The difference as regards nitrogen results mostly from different estimates of nitrogen loss
from land, instead.
The study further shows that of the total Italian load about 50-55% of the generated
phosphorus from all sources, domestic environment, agriculture and animal husbandry,
respectively, flow into the North basin of the Adriatic Sea across less than 5% of Italy's total
coastline. Because of proportionality between phosphorus and nitrogen in rivers, it can be
assumed that similar proportions hold for the total nitrogen load, although the relative contribution
from component sources are at variance.
Whatever the uncertainty of the absolute loading values may be, the Italian study, in as
far as it carefully considers the distribution of loads according to source category and major
hydrographic basins, can serve as a model to be followed by other Mediterranean countries.
Data of this sort provide the basis on which to develop management strategies. Yet, besides the
knowledge of such gross facts, knowledge of the basin internal pathways