Abstract: | The physical-chemical properties of the water are defined by multiple parameters. The most important parameters for the fish’s life are the pH, dissolved gases, suspended organic matter, ammonia content, nitrites, nitrates, phosphates, chlorides, hydrogen sulfide, metals, and detergents. Romanian Standard STAS 4706/1988 presents the water quality indicators values. In accordance with these indicators, the surface waters are divided into three quality categories. By the written disposition no. 1146/2002, the water quality parameters values used for aquaculture fish breeding and the second category were bring up to date. Because of this reason, in this project it is compared the evolution of the main chemical parameters of the supplied water from Danube and Brates lake and used for the anthrop aquatic ecosystem – Brates in the period 2002-2005. There were examined water pH, dissolved oxygen content (mg/L), decomposing organic matter (mg of KMnO4/L of water), ammonia (mg of NH3/L of water) and nitrites (mg of NO2-/L of water), parameters which indicate, in the situation of exceeding of the admissible limits for culture cyprinids, that there are possible some pathological states at fish. [1 - 3]. Comparing the same water parameters values for the two supply sources, the Danube and Brates Lake, we can see a visible difference. The Brates lake water has a bad quality and it is not indicated for the aquaculture use. |
