Evaluation of the H2S method for detection of fecal contamination of drinking water

Overview

Lack of access to laboratories or field analysis kits is an obstacle to the provision of microbiologically safe drinking water to many communities and people worldwide. In an effort to overcome this problem, a number of alternative indicators and tests to detect fecal contamination of drinking water have been proposed and developed. Some of these proposed fecal indicators and their tests are simple, low cost and do not require a microbiology laboratory or bacteriological field test kit. Some of these simple, low cost fecal indicator tests have come into use in actual drinking water supply practice. Prominent among these is the so-called hydrogen sulfide or H2S test, which is intended to detect or quantify hydrogen sulfide-producing bacteria, considered to be associated with fecal contamination.

The purpose of this report is to review the basis of the hydrogen sulfide test as a measure of fecal contamination of drinking water and the available scientific and empirical evidence for and against the test as a valid, useful and reliable measure of fecal contamination and drinking water quality. The report addresses the fundamental microbiological considerations of the test, including its chemical and biochemical basis, what organisms it detects and how it detects and quantifies them and the reported experiences with its practical application to assessing water quality.