This article presents evidence that the average number of coliforms in monitoring samples is a poor estimate of the mean coliform density of the distribution system. Results of various studies that led to this conclusion are discussed. The evidence includes variance in coliform counts, inadequacy of sample numbers, data truncation caused by limitations of the examination methods, changes in sample densities during storage between the time of sample collection and time of examination, and false results that may be due to changes in the coliform densities of samples during transit to the laboratory, turbidity or noncoliform bacteria in the water sampled, the physiological state of the coliforms, the species of coliforms, or sampling and analytical protocols. A regulation based on the fraction of monitoring samples with coliform densities greater than a preselected limit is recommended as a feasible alternative to the current microbiological maximum contaminant level. Includes 28 references, tables.
| Edition : | Vol. 76 - No. 11 |
| File Size : | 1
file
, 1.8 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 5 |
| Published : | 11/01/1984 |
