1992 Volume 38 Issue 1 Pages 28-37
Heterotrophic bacterial populations in a total of 22 stream waters polluted in different degrees were investigated by analyzing correlations with water quality variables. Colony-forming units on polypeptone-yeast extract-glucose agar plates correlated significantly with the concentrations of suspended solids, chemical oxygen demand and total organic carbon. Four hundred and thirty-four strains isolated from 22 stream waters were classified into 60 types according to the characteristics of colony color, motility, Gram stain, catalase production, oxidase production and oxidation-fermentation (O-F) test. In relationships between the percentage of the 60 types of isolates and water quality variables, YA1, YI, and NPG type positively, and NPK type negatively correlated significantly with many of the variables. All of these bacterial types were Gram negative bacteria ; the YA1 type was a yellow pigmented, non-motile, catalase-positive, oxidasenegative and O-F test-negative bacterium (Flavobacterium sp.) ; the YI type was a yellow pigmented, motile, catalase-positive, oxidase-negative and O-F test-negative bacterium (Pseudomonas sp.) ; the NPG type was a non-pigmented, motile, catalase-and oxidasepositive, and O-F test-oxidative bacterium (Pseudomonas sp.) ; and the NPK type, a non-pigmented, motile, catalase-negative, oxidase-positive and O-F test-negative bacterium (unknown sp.). These results suggest that YA1, YI and NPG types may be present predominantly in polluted waters and the NPK type in non-polluted waters, that is, that they may be good candidates as pollution indicators. The percentages of total YA1, YI and NPG types correlated strongly with most of the water quality variables.
