Vízügyi Közlemények, 1978 (60. évfolyam)
1. füzet - Kaurek Róber-Kovács Árpád: A Dél-Balatonba ömlő felszíni vízfolyások hatása a Balaton vízminőségére
72 Kaurek R.—Kovács A. The impact of streams discharging into South-Balaton oil the quality of lake water By R. Kaurek and A. Kovács, Chem. Engrs Lake Balaton is situated in the western part of Hungary, in the area enclosed by the Danube and the Dráva rivers. The lake has the largest surface area not only in Hungary, but in Central-Europe. The shallow lake of 600 sq. km water surface area was formed along a fault depression. In the present paper the polluting effects of the streams discharging into the southern part of the lake, further of the marshes which communicate with Lake Balaton are examined. The bulk of the lake water was found to correspond to the COMEA specifications for Class I fresh water. The enrichment and accumulation of inorganic plant nutrients presents, however, the greatest menace to water quality. This is the reason why investigations in the catchment tributary to the southern part of the lake have been focussed primarily on the inorganic plant nutrient substances. The streams discharging into the southern part of the lake belong to the quality classes II to IV. The highly polluted group comprises the canals draining the adjacent marshes and wet pastures. These waters are characterized by their high concentration of total dissolved salts, and generally by the prevalence of magnesium-, sulphate-, hydrogencarbonate types. The permanganate oxidizable organic content was also found to be high. These investigations have succeeded in demonstrating that over the year 1975 these marsh drainage waters were responsible for discharging 63 per cent of the chemically oxidizable organic substances (COD s p), 77.9 per cent of the total dissolved solids, 37.3 per cent fo the total nitrogen, 26.4 per cent of the phsosphorus and 15 per cent of the dissolved phosphorus. The surface areas poluted by the marsh drainage waters were identified by aerial photography and found to be 2.64 sq. km in size in South-Balaton. Humic acids lend these marsh waters a typical yellowish-brown colour. Infrared spectroscopy has revealed the bulk of the colour substances to consist of aromatic hydrocarbons having 5 to 6 carbon atoms. Photooptical transparency investigations on the marsh-drainage waters have yielded the following results : — The humic substances tend to filter out most of the ultraviolet radiation. — Depending on the colour of the marsh-drainage water, light absorption is considerable also in the 350 to 500 nm wavelength range. — The marsh water is perfectly transparent to waves in the 600 to 700 nm band, promoting thus favourably the assimilation processes. — At dilution ratios higher than 1:50 the mixture of marsh: Balaton water shows transparency characteristics similar to pure Lake Balaton water. — Pilot studies into storage have provided guidance in selecting reservoir sites. The main particulars of the reservoirs suggested l'or construction have been compiled in tabular form. * * * Einfluss der südlichen Zubringer des Balaton-Sees auf das Seewasser von Dipl. —Chemieing. Róbert Kaurek und Dipl. — Chemieing. Árpád Kovács Der Balaton-See befindet sich im westlichen, zwischen der Donau und der Drau liegenden Teil Ungarns. Er ist das grösste stehende Gewässer nicht nur Ungarns, sondern ganz Mitteleuropas. Sein grabenartiger Becken ist flach, seine Wasserfläche beträgt 600 km 2. Die Studie befasst sich mit dem wassrverschmutzenden Effekt der südlichen Zubringer des Sees sowie der Gewässer der dem südlichen Seeufer entlang befindlichen Haine. Es wurde festgestellt, dass das Wasser des Sees nach den RGW-Normen der Kategorie Nr. I. (reines Wasser) entspricht. Sein Qualität wird vor allem durch die Anreicherung an anorganischen Pflanznährstoffen gefährdet. Deshalb wurden die im
