Introduction
1.1 Background Information
Fresh water sources can be broadly categorized into groundwater and surface water (Chapman, 1992). Surface water can again be sub-divided into ‘‘running’’ surface water bodies and ‘‘stationary’’ surface water bodies. Examples of the former include rivers, streams, and brooks while examples of the latter include lakes and ponds. The most abused of all surface water bodies are the running surface water bodies because people tend to believe that by disposing their wastes into these running water, they have been rid of their waste disposal problems. In spite of its relative abundance, water is still a very scarce resource when it is needed in its fresh form because 97.5% of all available water is salt water (Krantz and Kifferstein, 2007; UNESCO, 2006). Of the remaining 2.5%, 70% of it is frozen in the polar ice caps. The other 30% is mostly present as soil moisture or is trapped in underground aquifers. In the end, only 0.007% of all water on earth is readily accessible as fresh water for direct human use (UNESCO, 2006; Krantz and Kifferstein, 2007).
1.1.1 Water Sources Distribution in Nigeria
Record shows that 29% of Nigerians live in the rural areas, 33% reside in small towns and 38% live in the urban areas (FGN, 2000). World Bank (2005) also revealed that 91% of Nigerians living in the rural areas (which translate to 37 million Nigerians, using the 2006 census data) had no access whatsoever to treated water. Most Nigerians derive their water from surface water (springs/stream/rivers), hand dug wells, rain harvesting, pipe borne water, boreholes and vendors (FGN, 2000). It is estimated that 48% (about 67 million) Nigerians harness surface water for their domestic needs, 57% (79 million) use groundwater, 20% (27.8 million) harvest rain, 14% (19.5 million) have access to pipe borne water while 14% use boreholes (FGN, 2000). According to Ahianba et al., (2008) 33.82% (47.3 million) Nigerians depend exclusively on surface water for their domestic water supply, 28.27% (39.3 million) on hand dug well sources, 24.38% (33.9 million) on pipe borne water, 11.83% (16.4 million) on borehole water and 1.7% (2.4 million) on water vendors (Fig. 1.1). Another interesting statistic suggests that 54.6% (75.9 million) Nigerians use pit latrines exclusively, 13.71% (1.91 million) use water closet exclusively, 0.58% (806,
200) use the bucket system and 31.16% (43.3 million) Nigerians use other unsanitary methods (Fig 1.2). Some of these unsanitary methods include defecating in open fields and disposal into surface water bodies (Ahianba et al, 2008). When rain falls, all the defecations disposed on land get washed down into the surface water bodies as non-point source pollution. This is beside the pollution being discharged into surface water bodies by industries. It can be inferred, therefore, that 47.3 million Nigerians are potentially at risk of epidemic outbreak if our surface waters are not adequately protected through legislations guided by scientific facts.
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