Evaluation of the H2S test as an indicator of waterborne fecal contamination

A major limitation of the H2S test for the detection of fecal bacteria is the current uncertainty and variability of its sensitivity and specificity for bacteria of fecal origin based on data from available studies. The purpose of this research was to determine whether a quantitative H2S test could correctly identify fecally contaminated water samples and determine if there was any relationship between the test results and diarrheal disease risk. Using culture-based biochemical and culture-independent molecular techniques, this research focused on determining the types of microbial community members, including fecal indicator organisms, pathogens, and other microbes present in human sewage samples that are detected in a quantitative H2S test as microorganisms of concern to human health. Sewage waters, natural waters from the United States, and household drinking water samples from central Vietnam were analyzed for the production of H2S producing bacteria. The water sources tested in this study were chosen based on the 2002 World Health Organization Guidelines for Drinking Water Quality to be representative of commonly used drinking water sources worldwide and included a rainwater cistern, a protected lake, a well in an agricultural setting, and a well in a forested area. For the culture-based method, samples were analyzed for the presence of fecal bacteria by spread plating the water sample enrichment culture onto selective agar media. The isolates were then: (1) tested to determine whether they were H2S producing organisms, and (2) identified to the genus and species level using biochemical methods (primarily Enterotube and API 20E). Terminal Restriction Fragment Length Polymorphisms (TRFLP), a quantitative molecular technique developed for rapid analysis of microbial community diversity, was used to identify microbial community members and understand microbial community differences in water samples. Overall, these experiments showed: (1) when a water sample tests positive for H2S, there are fecal bacteria in the water sample; (2) greater than 70 percent organisms isolated by the culture based biochemical identification method were also identified using TRFLP analysis; (3) although community composition differed and changed, there was a fairly stable group of identifiable microorganisms in the water samples; and (4) a quantifiable, low-cost version of the H2S test costing less than 0.75USD had a similar relationship to diarrheal disease as did standard E. coli methods for testing drinking water samples in a developing country

Superfund Community Information Needs Assessment: Four Case Study Sites in North Carolina

Citizens and communities need information on contamination, routes of exposure, possible health effects, and alternatives for cleanup at Superfund hazardous waste sites in order to participate effectively and meaningfully in government decisions about site remediation and cleanup. It is unclear what kinds of information these stakeholders want, need, and/or can use. This paper assessed how technical and scientific information was used at four North Carolina case study sites and proposed effective ways to communicate to citizens and other stakeholders in communities near hazardous waste sites. The research used three surveys to examine stakeholder views, including how hazardous waste information is distributed, how community involvement activities are conducted, whether technical assistance was available, and the level of trust in different information sources and entities. Results showed that local government officials had received and understood technical and scientific information. Community members reported that they did not know where to go for technical and scientific information, but were uniformly interested the health and environmental effects of contamination. Although the effectiveness of public meetings was perceived to be low by community respondents, both local government officials and community respondents wanted more information on the dates, times, and locations of public meetings. Engaging the public early in the process increased their involvement. Although responses at different sites showed some commonalities, each site should be approached individually. No one-size-fits- all plan for community involvement will be adequate.Master of Science in Public Healt

The compartment bag test (CBT) for enumerating fecal indicator bacteria: Basis for design and interpretation of results

For the past several years, the compartment bag test (CBT) has been employed in water quality monitoring and public health protection around the world. To date, however, the statistical basis for the design and recommended procedures for enumerating fecal indicator bacteria (FIB) concentrations from CBT results have not been formally documented. Here, we provide that documentation following protocols for communicating the evolution of similar water quality testing procedures. We begin with an overview of the statistical theory behind the CBT, followed by a description of how that theory was applied to determine an optimal CBT design. We then provide recommendations for interpreting CBT results, including procedures for estimating quantiles of the FIB concentration probability distribution, and the confidence of compliance with recognized water quality guidelines. We synthesize these values in custom user-oriented 'look-up' tables similar to those developed for other FIB water quality testing methods. Modified versions of our tables are currently distributed commercially as part of the CBT testing kit

A Summary Catalogue of Microbial Drinking Water Tests for Low and Medium Resource Settings

Microbial drinking-water quality testing plays an essential role in measures to protect public health. However, such testing remains a significant challenge where resources are limited. With a wide variety of tests available, researchers and practitioners have expressed difficulties in selecting the most appropriate test(s) for a particular budget, application and setting. To assist the selection process we identified the characteristics associated with low and medium resource settings and we specified the basic information that is needed for different forms of water quality monitoring. We then searched for available faecal indicator bacteria tests and collated this information. In total 44 tests have been identified, 18 of which yield a presence/absence result and 26 of which provide enumeration of bacterial concentration. The suitability of each test is assessed for use in the three settings. The cost per test was found to vary from $0.60 to$5.00 for a presence/absence test and from $0.50 to$7.50 for a quantitative format, though it is likely to be only a small component of the overall costs of testing. This article presents the first comprehensive catalogue of the characteristics of available and emerging low-cost tests for faecal indicator bacteria. It will be of value to organizations responsible for monitoring national water quality, water service providers, researchers and policy makers in selecting water quality tests appropriate for a given setting and application