Evaluation of different strategies for deploying the H2S test to detect microbial contamination of drinking water

The hydrogen sulphide (H2S) test has been proposed as a presence-absence, low-cost field test to detect microbial contamination for nearly 30 years and is now widely used in many countries. The objective of this study is to identify different strategies for deploying the test and assess how each might be affected by the test’s accuracy. Evidence on the H2S test’s accuracy is drawn from a recent systematic review. We identified six different strategies for deploying the test based on a literature review. Three strategies used the H2S test in isolation, while the other three used the H2S test in combination with standard, laboratory-based methods or alongside sanitary risk inspection surveys. We conclude that using the test in combination with laboratory-based methods or sanitary risk inspections reduces the problems posed by false positive H2S test results. However, such strategies may be more costly and complex to implement.