2JATE Szervetlen és Analitikai Kémiai Tanszék

hopi@sol.cc.u-szeged.hu

This paper contains elaborated state of the Tisza Maros and Third Körös rivers water quality in Hungarian southern plain (Dél Alföld), and it presents application of Fuzzy sets on water quality evaluation.

Fuzzy sets enable us to describe and handle vague or ambiguous notions such as “set of real numbers which are much greater than 1”, “set of beautiful women”, or “the set of tall men”. Fuzzy sets theory presents applicable mathematical tool for dealing with problems related to unprecisenes, indefiniteness and subjectivity. Fuzzy logic is most frequently used for complex systems modelling where application of other methods creates extreme difficulties in determination of correlation that exist between some variables. In this paper theory of Fuzzy sets is connected with problems related to evaluation of the Tisza river water quality which opens new horizons in application of fuzzy logic in Hungary.

Investigation was undertaken in order to rank observed locations regarding to their water quality by the oxygen related parameters, nutrient related parameters, micro pollutants and toxic parameters. Evaluation was conducted on following locations in Hungarian southern plain: the Tisza river at Mindszent, Tápé and Tiszasziget; the Third Körös river at Magyartes; the Maros river at Nagylak, Makó and two kilometres before its inflow to Tisza. Investigation took into the consideration both, annual concentrations of observed parameters of water quality and annual load of pollution given through annual load of water quality parameters. Following parameters of water quality were taken into the evaluation: pH, electric conductivity, O₂, Fe, Mn, NH₄-N, NO₂-N, NO₃-N, PO₄-P, COD, BOD₅, Al, As, Hg, Cr, Ni, Cu, etc.