Work in progress and drafts for the ongoing revision of the guidelines
Evaluation of the H2S method for detection of faecal contamination of drinking-water
Evaluation of the H2S method for detection of faecal contamination of drinking-water is included in the plan of work for rolling revision of the WHO guidelines for drinking-water quality.
Background
WHO receives many requests for information and comment on this microbiological test. It is a potentially important issue, particularly for developing countries. The purpose of the supporting document Evaluation of the H2S Method for Detection of Faecal Contamination of Drinking-water is to review the basis of the hydrogen sulfide test as a measure of faecal contamination of drinking-water and the available scientific and empirical evidence for and against the test as a valid, useful and reliable measure of faecal contamination and drinking-water quality. The draft 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. A problem is that the test is non-specific and may provide false positives for sulfide in some waters that are not suffering sanitary contamination, but rather contain reduceable sulfate. That will limit its use by decision-makers. One general comment was that the draft was ambiguous as to the value of the test and its utility as a screening tool.
Expected end-product(s)
Revised draft report for review in early 2006; stand-alone supporting document for publication post-2006
This document is now available as a draft for comments.
Comments on the draft would be welcome and submitted by e-mail before 31 October 2004.