EVALUATION OF THE PRESENCE-ABSENCE (P-A) TEST - A SIMPLIFIED BACTERIOLOGICAL TEST FOR DETECTING COLIFORMS IN RURAL DRINKING-WATER OF INDIA

One thousand three-hundred and ninety-four drinking water sources comp rising ground water, surface water and piped supplies were tested in o rder to compare the presence-absence (P-A) test with standard MPN meth od to detect coliforms as indicators of water quality. Out of 1394 sam ples, 1074 (77.04%) and 1030 (74.88%) were positive by the MPN and P-A test, respectively. The P-A test detected 96% of the positives detect ed by the MPN test. The P-A test may be effectively used as a rapid sc reening method to detect coliform contamination in less polluted sourc es such as ground water and piped supplies.