Vízügyi Közlemények, 1985 (67. évfolyam)
3. füzet - Ralovich Béla-Tóthné Jeges Sára-Kiss István-Braun György-Joó Ottó: A Balaton, a Zala és hat déli parti vízfolyás minőségének alakulása
438 Ralovich В., Tóthné Jeges S., Kiss !.. Braun Gy. és Joó O. Quality development of Lake Balaton, River Zala and of six small rivers on the southern coast by Dr. B. RALOVICH, Physicien, С. Biol. Sc., S. TÓTHNÉ JEGES (Mrs.), Mathematician, C. Sociol. Sc., I. KISS, Chemical Engineer, G. BRAUN, Chemist and Dr. O. JOÓ, Civil Engineer Water samples from 1979 to 1983 were investigated for their chemical, physical and biological components (reactive P0 4 " total P, NO3, total N, COD SC r, BOD s, 0 2 content, pH, N0 2 , Ca + +, NH4 , Na +, Cl , K + , S0 4 , HCO3 , total dissolved salt, water temperature, number of germs proliferating at 20°C, number of germs proliferating at 37°C, number of Clostridia reducing sulfite, number of coliform bacteria, number of coli faecalis, number of streptococci faecalis) in River Zala (at Fenékpuszta), in six small rivers on the southern coast (Kőröshegyi-séd, Ordacsehiárok, Keleti-Bozót, Tetves-patak, the canal of Imremajor and Nyugati-övcsatorna at route Nr. 7), at stations along the southern coast of the lake (Balatonberény, Fonyód, Balatonszemes, Zamárdi), and at stations in the middle of the lake (Balatonberény, Badacsony, Balatonakaii, and Tihany). It was concluded that the quality of River Zala has not improved but rather has deteriorated during the past 5 years as far as a part of the components was concerned despite investments made for the improvement of quality. This fact urges the not belated, accurate definition of the functional tasks and capacity of the reservoir of Kis-Balaton. Water quality of the six small rivers on the southern coast changed with an unstable degree and character during these past years. Unambigous improvement —extending to all components —could not be observed. In case of the canal of Imremajor a definite deterioration was recorded. The small rivers have a decisive influence on the quality of the waters in the coastal area used primarily for bathing. Pollution load of the southern coast could be diverted easiest by a shunt-canal conducted directly in the Sió River. Coastal and middle-lake samples were investigated via factor-analysis. In case of the coastal samples 10 factors, of the middle-lake samples 7 factors were separated. Based on information gained by recent data it was concluded that there are favourable but at the same time unfavourable tendencies alike. Among the former one may mention the reduced concentration of the BOD 5, COD SC t, total N. dissolved oxygene and of the NH4 content. These point to a reduction of the processes leading to eutrophication. These trends are possibly interconnected with an increase of the concentration of Ca + + and HN0 3" . Unfavourable signs are the increased concentrations of reactive PO4 total P, N0 3", SO4, Na + , СГ, and K + . Sanitary discipline has been improved in the area. Temporary but adequate disposal of sucked wastewaters was appropriately organized along the southern coast. Faecal load in the lake reduced. This statement was based on the evaluation of bacteriological investigations. 134 fungi were isolated in the lake. These represented 52 species and 24 genera. From water samples only 11 species and 1 genus could be isolated up till now. In the coastal rivers 241 fungi were isolated. These were categorized in 75 species and 32 genera. 19 species and 8 genera were found in these rivers. Further investigations are needed for a better understanding of the ecosystem of the lake.
