EVALUATION OF DISINFECTED AND UNTREATED DRINKING-WATER SUPPLIES IN CHILE BY THE H2S PAPER STRIP TEST

Potable water studies have suggested that the presence of coliforms in contaminated potable water supplies was also associated with hydrogen sulphide producing organisms. Based on these observations, a paper strip testing method was used and modified to screen for bacteriological contamination of potable waters. The simplicity and low cost of the H2S paper strip technique, if applicable to tropical and subtropical potable waters, would provide countries with an affordable, locally produced water quality monitoring test. To evaluate the feasibility of this test, 622 drinking water samples, disinfected and non-disinfected, were collected from three districts in Chile and tested by the H2S paper strip method and total coliform MPN method and for coliphages. Results from this study indicated that (1) in treated and untreated drinking waters tested by the H2S paper strip and total coliform MPN test, the H2S test produced slightly more (10%) positive findings and (2) when the positive H2S paper strip samples were tested for coliforms, the number of H2S positive samples containing coliforms was similar to the number of samples testing positive by the total coliform MPN.