This paper describes the findings of a study conducted in Nelvoy village in Vellore district, Tamil Nadu, India.
The study attempted to understand the phenomenon of water contamination in the village by using GIS as a tool to locate and map water supply and sewage distribution systems in the village, in relation to human and animal dwellings, their wastes, sanitary practices and their connections with drinking water quality for a clearer understanding of the connections between these factors and possible solutions to the problem.
Safe water is one of the most important felt needs in public health in developing countries in the twenty first century. However, in India, as high as 72.7% of the rural populations still do not have access to safe water, nor any methods of water disinfection and 74% have no sanitary toilets. Studies have shown that a number of sociocultural practices including open air defecation, tethering of animals near human dwellings, proximity ot animal faecal matter have found to lead to water contamination resulting in outbreaks of diarrhoeal diseases.
The paper argues that the key to providing microbiologically safe drinking water lies in understanding the various mechanisms by which water gets contaminated, and then formulating interventions at critical points to decrease and prevent contamination of drinking water. This study aimed at undertstanding the mechanisms through which the water in the villages was contaminated by identifying the locations of the water supply and sewage distribution systems in relation to human and animal dwellings, their wastes, sanitary practices in the village and their correlations with the contamination of water sources.
Geographic information system (GIS) tools were used to demonstrate spatial relationships for a clearer understanding of problems and possible solutions. Streets, houses, water supply, garbage, sewage channels, functional toilets in the village and community defaecation areas in the surrounding fields were mapped using a hand-held global positioning system (GPS) receiver Garmin GPS V (GARMIN International Inc., Kansas, USA). Data were analyzed using SPSS version 12.0 for windows (SPSS Inc., Chicago, Illinois; 1989-2001) software
The study found that water in the village was microbiologically unfit for consumption. Open air defaecation and the practice of tethering animals close to human dwellings contributed to the conversion of large areas of land in and around the village into ‘defaecation or faecal fields’. Animal and human faecal contamination of topsoil was evident on inspection of these areas. A mapping of these areas showed reservation of a substantial land area for this purpose, and these ‘faecal fields’ potentially put the village at risk of flooding with faecal material from surrounding areas during rains.
Poor planning and maintenance of the water supply system led to inappropriate usage and over-exploitation of available resources. Analysis using direct observations supplemented by GIS maps revealed poor planning, poor engineering design and lack of policing of the water distribution system causing possible contamination of drinking water from sewage at multiple sites. The study concluded that until appropriate engineering designs for water supply and sewage disposal to suit individual village needs were made available, point-of-use water disinfection methods could serve as an interim solution.
The journal also includes a commentary on the paper, which highlights the pandemic nature of water borne diseases and calls for a collective action by developing countries to solve their problems by themselves, using tools such as risk analysis and GIS technologies on a large scale.
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