Bacteriological Assessment of Drinking Water Using H2S Test

Drinking water is an important resource that needs to be protected from pollution and biological contamination. Water borne diseases continue to be a dominant cause of water borne morbidities and mortality all over the world and helps in the spread of enteric diseases. A total of 38 water samples were tested by the new H2S test methods. According to the H2S test, 24 (63.15%) of the 38 samples had fecal coliforms, while 14 (36.84%) had no faecal contamination. From the 24 positive samples 47 isolates were investigated for the identification of faecal contamination. Out of 47 isolates, 21 (44.70%) were Pseudomonas, 14 (29.78%) were E.coli, 6 (12.76%) were Salmonella, 4 (8.5%) were Klebsiella and 2 (4.25%) were Staphylococcus spp. It is evident from the data presented in this work that H2S producing organisms are consistently associated with the presence of coliforms in water. Enteric bacteria such as Salmonella, and certain species of Klebsiella also produce H2S. The predominant H2S producing bacteria found in polluted drinking water in the present study were Salmonella spp., Klebsiella, Staphylococcus, and H2S producing variants of E.coli. Thus study indicated that the H2S test is a reliable and alternative indicator of fecal contamination in drinking water quality surveillance and screening of large number of water samples in short duration in the field where laboratory facilities are limited.