The Long Term Investigation of the River Danube Water Quality in the Yugoslav Section According to Microbiological Parameters

The results of investigations of Danube river water quality in the Yugoslav section in the period from 1975 to 1988 are presented. The estimation of water quality was based on the numbers of heterotrophs, T/H ratio, and enzymatic activity. In addition, the number of bacteria of some physiological groups was determined. The results indicate that there was a deterioration of water quality in the investigated period. The number of heterotrophs was observably lower in the period from 1975 to 1978 than it has been in recent years. The constant worsening of the water quality is also evident from the the T/H ratio and enzymatic activity measurements.