The Upper Tisa Valley. Preparatory proposal for Ramsay

Table 6. Saprobiological characteristic of occasional sites on River Tisa in spring 1991
In the summer much attention was paid to the influence of inhabited areas on
the saprobiological condition of River Tisa and its tributaries. At occasional points
samples were taken repeatedly, which confirmed a disastrous state of the water
ecosystem below large cities. The largest contaminator with ordinary sewage is the
city Rahiv. Water quality, as suggested by ciliate bioindicators, was estimated here to
be constantly upper alpha-mesosaprobic to polysaprobic (Table 7.). If we take into
account the possibility of the breakdown of any of the sewage treatment systems, we
can quite obviously predict the increase of saprobity indices in a cold season, as is
observed in real life (Table 7.).
It is well known that the functional activity of hydrobionts falls with a decrease
in temperature, which is reflected in their reduced ability to mineralise organic
substances. Truly enough, when River Tisa is occasionally polluted on its reach above
the cities, the effect is stronger in autumn than in summer.
Unexpectedly, there was an indication of pollution even in a state wildlife area,
namely the high-mountainous lake Sinevir. While the main water body was
oligotrophic and oligosaprobic, the beach showed mesosaprobic pollution. It is
associated not only with the increase of poorly supervised tourism, but also with the
activity of breeding domestic ducks by the local inspectors.
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