OPPELTOVÁ PETRA, HUBAČÍKOVÁ VĚRA, NAJMAN JAKUB. 2015. Water Quality Development in the Semíč Stream. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 63(3): 803-813. The aims of the work were to analyse selected quality indicators of a small water stream called Semíč and evaluate the results based on the valid legislation. Eight sampling profi les (SP) were selected and water was sampled four times a year in the period May 2013-April 2014. PH, conductivity, oxygen content

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... and temperature were measured directly in the fi eld. Subsequently, ferrum, nitric nitrogen, ammoniacal nitrogen, sulphates, chlorides, chemical oxygen demand tested using dichromate, total phosphorus, total nitrogen and manganese were analysed in the laboratory. Analyses of selected heavy metals -zinc, copper and aluminum -were carried out in spring 2014. The results were classifi ed in compliance with Government Decree (GD) No. 61/2003 Coll., as amended, and Czech standard ČSN 75 7221. The results of the period 2013-2014 were compared with the results from 2002-2003 and 1992. The resulting concentrations of substances manifest considerable instability during the year, which can most likely be attributed to large changes in fl ow rates in diff erent seasons. When comparing the values to older results, it can be concluded that the concentrations of a number of substances have decreased; by contrast, others have increased. An extreme increase in copper was detected, where the concentration exceeded the environmental quality standard several times.