摘要：The aim of this study was to determine the anthropogenic influence on the sanitary-bacteriological sate of the waters of Kardzhali reservoir. The seasonal dynamics of the total count of Esherichia coli, fecal streptococci (FS), and Clostridium perfringens were studied for the period April - March 2011/12 in the waters of the reservoir. Samples were taken from six stations located in the lake zone and the transitional zone of the dam-lake and one station at river Arda. With the exception of August and October the count of E. coli and FS did not exceed 30 cfu / 100 ml and 20 cfu / 100 ml respectively. In August was established an increase in the values of the two microbial indicators and this trend continued during November. Statistically significant differences were established for the E. coli and FS count between the stations located in the lake zone of the dam-lake and those at the net-cage farms and Glavatartsi village, subjected to strong anthropogenic influence. Presence of Clostridium perfringens in the studied samples was established only during August, mainly at the stations located near the net-cage farms and near the dam. Total of 220 strains fecal coliforms were isolated and identified, in order to establish the basic species composition. All of them fall into 5 genera of the Enterobacteriaceae family
