MICROBIAL STATUS OF DOSPAT DAM LAKE, BULGARIA

T. Hubenova, S. Kostadinova, A. Zaikov, M. Marhova, I. Iliev

Abstract: The aim of this study was to determine the total count of main microbial indicators for the water quality of Dospat Dam Lake. Samples were taken from six stations situated in the aquatory of the reservoir and one station at Dospatska River. The seasonal dynamics of the total viable count (TVC 20°C), total coliforms (TC), E. coli, fecal streptococci (FS) and C. perfringens were studied for the period April 2011 – March 2012. The values for the TVC 20oC were within range of 1.103cfu.100 mL–1 to 39.103 cfu.100 mL–1, without statistically significant differences between stations (ANOVA, P > 0.05). The average values for TC varied from 10 cfu.100 mL–1to 100 cfu.100 mL–1and in August it rose to 1000 cfu.100 mL–1 with higher numbers near the net cage farms (ANOVA, P < 0.005). Presence of E. coli, FS and C. perfringens during the spring months was not established. Slight increase of the sanitary-state indicator was observed in August with values of 26 cfu.100 mL–1, 20 cfu.100 mL–1 and 10cfu.100 mL–1 for E. coli, FS and C. perfringens respectively, with similar trends in November. Coliforms were characterized by low species diversity with domination of Serratia marcescens, Pantoea aglomerans, Hafnia alvei and Enterobacter cloacae at stations tree, four and five. The highest number of species was observed at station six (near Sarnitza village).

Keywords: Clostridium perfringens; Dospat Dam Lake; Escherichia coli; FS; TC; TVC 20C

Date published: 2017-09-28