All over the world numerous attempts are being made to find out a simple and reliable method which does not need elaborate set up, inexpensive and can be performed by common man in rural area where people have compelled to drink highly contaminated water. One such method is H2S Strip Test.The presence of coliforms in drinking water is consistently associated with hydrogen sulphide producing bacteria. Many pathogens also produce hydrogen sulphide. For the reason in H2S Strip Test method, water borne hydrogen sulphide bacteria act as indicators of faecal pollution. An iron rich medium described which supports growth of hydrogen sulphide bacteria present in water. Hydrogen Sulphide produced during growth of bacteria reacts with iron and turns water sample black, indicating the presence of harmful pathogen in water sample.
The International Development Research Center (IDRC) of Canada had supported a research project for evaluation of four simpler and economical methods for bacteriological testing of water quality for their accuracy, simplicity and cost. Researchers from Brazil, Chile, Egypt, Malaysia, Morocco, Peru, Singapore and Thailand had participated in the project. From their findings it can be concluded that H2S strip test is probably the best and simpler method to test remote water supplies, as well as for use in city and town laboratories. It is the most economical test for developing countries.
Recently UNICEF India has set up an expert committee to improve the original H2S STRIP TEST to make it more sensitive, efficient and reliable. The task of the committee is to recommend the changes and modifications in the test so as to make more reliable.