Final Report - ICPDR

0,200
0,180
0,586
mg/l
0,160
Concentration of PO4-P (mg/l)
0,140
0,120
0,100
0,080
0,060
Tisza
tributaries
0,040
0,020
0,000
0 100 200 300 400 500 600 700 800
Distance (km)
Figure 4.1.1.4 Amount of orto-PO 4 -P in the Tisza and its tributaries, ITR, 2001
The ITR sampling sites and four tributaries had the same amount of orthophosphate
phosphorous. Three tributaries exceeded the average value (Figure 4.1.1.4): the
Bega, the Sajó and the Zagyva. The last one was characterized by the large overall
maximum value (0,526 mg/l).
It can be concluded that the amounts of the most important inorganic nutrient
substances were not high in the Tisza River. There were only few tributaries where
extreme values were detected like the Bega (ammonium and nitrite nitrogen) and the
Zagyva (orthophosphate phosphorous) most probably due to permanent organic
load. In case of orthophosphate phosphorous concentration the Sajó has a little bit
increased value also, due to the communal wastewaters of Miskolc city but this is not
as much as in case of the Zagyva at all.
In order to evaluate the nutrient load of the Tisza and its tributaries it seems to be
worthwhile to take the concentration of chlorophyll-a in consideration, as well. The
degree of trophity as the realized primary production in water due to planktonic
eutrophycation can be explained this way.
In case of the Tisza River it is clear that the concentration of chlorophyll-a is not high,
especially in the Upper Tisza stretch. The maximum value was measured at the
downstream end of the Kisköre Reservoir. However, the Zagyva River with the
detected 73 µg/l chlorophyll-a concentration seems to be an outstanding water
course in that respect, too. It looks like the key element in case of that explanation
should be the phosphorous. The origin of o-phosphates is most probably the large
number of villages and cities along the Zagyva that is characterized by small flow
rate especially during late summer, early autumn.
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