Application of a water-related environmental health epidemiological process : a guide for environmental health practitioners

Abstract

One of the more suitable methodologies to follow to assess the impacts of environmental factors on the health of humans would be the epidemiological process. Environmental health practitioners in South Africa are, however, ill equipped to use this process and thereby lose an effective tool in its service abilities. This situation is aggravated by the lack of a suitable guide that can be used to lead such a process. It was therefore decided to conduct a study that could lay the foundation for developing a guide for using epidemiology in environmental health practice under typical South African conditions. An epidemiological survey was conducted within an extended research programme to study the effects of stored domestic water on the health of the consumers in Section K, Botshabelo, a developing urban settlement in the south-eastern Free State. In the study area, people used various types of containers to move drinking water from the municipal supply (public standpipes or yard taps) to their individual dwellings to store for daily use. The main aim of this study was to determine whether the people's water-use patterns that had developed around this method of haulage-and-storage had a detrimental effect, specifically diarrhoea, on their health. The study design entailed an environmental health survey, which provided an opportunity to compile a guide for the application of such an environmental health epidemiological survey. This guide was written based on the experiences gained from conducting the community-based survey. During the survey, diarrhoea was used as an indicator of the health of the target community. Data were collected by means of a questionnaire designed for household respondents, completed by students. A proportional stratified sample of 300 households was randomly selected from a population of approximately 3326 households. Water provision, water storage, water use, sanitation, and personal hygiene were some of the key variables investigated in the study. Results indicated that infants (older than 1 year, up to 5 years old) were the age group that were affected most by diarrhoea. Container hygiene, container type (plastic or metal) and storage of water as well as poor sanitation in the area were variables related to the occurrence of diarrhoea. Other practices indicated by the survey as possible causes were unhygienic scooping of water from containers (including scooping-mug hygiene) and the presence of domestic animals in the household. The study indicated that an epidemiological survey could be appropriately applied to assess environmental health impacts although the results merely pointed towards tendencies. Several other potential variables such as food hygiene, baby-care hygiene as well as other personal and environmental hygiene practices were not investigated in this study. The use of an environmental health epidemiological study process can provide a useful investigative tool if suitably applied for the assessment of water quality effects on the health of humans. The guide developed from this study is seen to be provisional and is released for further evaluation, inputs and development.