THE AC/TC BACTERIAL RATIO

An inexpensive tool for indicating microbial quality in watersheds is presented that utilizes the conventional total coliform test, comparing the relative concentrations of different colonies that form on a membrane filter fed by m-Endo media. These bacterial colonies can be classified into 3 types;...

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Bibliographic Details
Published in:Journal of water and environment technology 2005-07, Vol.3 (2), p.271
Main Author: Montgomery Brion, Gail
Format: Article
Language:English
Online Access:Get full text
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Summary:An inexpensive tool for indicating microbial quality in watersheds is presented that utilizes the conventional total coliform test, comparing the relative concentrations of different colonies that form on a membrane filter fed by m-Endo media. These bacterial colonies can be classified into 3 types; typical (TC), atypical (AC), and background. The ratio of the concentrations of AC colonies to those of TC is related to water quality, fecal loadings, and fecal age. The AC/TC ratio relies upon shifts in populations between indigenous and introduced bacteria, with the indigenous bacteria providing a baseline against which the concentrations of the introduced are evaluated. When the AC/TC ratio is low (20) and can be related to healthier water quality conditions. Different types of runoff have different AC/TC values with human sewage at the lowest end of the spectrum with a value of 1.5 under normal conditions.
ISSN:1348-2165