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Urban Water Quality In Emerging Urban Centres: Case Studies From Nigeria .

Congress: 2015
Author(s): Akudinobi Enefeanya (Awka-Anambra state, Nigeria)


Keyword(s): Sub-theme 2: Surface water and groundwater,
AbstractINTRODUCTION: Developing countries, particularly in Sub-Saharan Africa, characteristically embark on rapid infrastructural, industrial, agricultural and several other socio-economic development programmes without commensurate environmental protection efforts. Predominantly, the motivating factor centers on fulfillment of electoral promises often made by politicians. In Nigeria as a developing country, the scorecards of persons involved at all levels of governance are mostly evaluated on this premise, averagely in line with the value system of the citizenry. Sequel to the continual problem of rural-to-urban migration linked to paucity of basic social amenities in rural and sub-urban areas, developing urban centers in Nigeria are characterized by hyke in population density, with correspondingly high waste output, and increasing competition among water users. Leb (2012) noted that population growth, economic development and climate change are putting increasing stress on global surface water resources. The risk factors in the area of water safety are thus necessarily high, though often either neglected or inadequately considered. The need thus exists for periodic qualitative assessment of public water supply sources, to review the state of water health. With growing population, continued economic development and climate change, international concern about satisfaction of basic human water needs is on the rise (Leb,2012). In this study, hydrochemical and microbial assessment of some public water supply sources was done in two state capitals, comprising Awka( in Anambra State) and Umuahia ( in Abia State), all in Southeastern Nigeria. The scope of the study has been limited by availability of funds. METHODOLOGY: Basic geological review of the areas was done to ascertain the dominant rock types and their hydrogeochemical implications, with emphasis on water quality. American Public Health Association (1992) standard for water quality assessment was adopted in this study. A total of forty water samples were collected (in two sets of twenty each) from the two towns, predominantly for hydrochemical and microbial tests. One set of the samples was on collection, filtered and stabilized with two-to-three drops of dilute hydrochloric acid (HCl) prior to preservation. This set of samples was used for all cation tests. The remaining set of samples was preserved without any additive, and used for all pH, anion and microbial tests. Both surface water and groundwater sources were sampled, using public reliance on such sources as the guiding principle. Atomic absorption spectrophotometry technique was used in all heavy metal tests, while titrimetric method was predominantly used for anion tests. All microbial tests were done with membrane filtration method. Field geological studies indicate predominance of shale and sandstone rocks in the areas. RESULTS AND DISCUSSION: The results of hydrochemical analysis of samples from Awka indicate that the major ionic constituents (including calcium, potassium, sodium, carbonate, sulphate, chloride, and nitrate) fall within the acceptable limits for drinking water(World Health Organization(WHO) 2004). Other base metals, including zinc, copper, chromium and magnesium were detected in trace (non-harmful) concentration. Cadmium occurrence was recorded in 100% of the water samples at objectionable values, while lead recorded 20% occurrence. Objectionable values of mercury was recorded in 80% of the samples, with 70% ranging from 0.2 to 0.7 〖mgl〗^(-1).Objectionably high coliform counts were recorded in 80% of the samples, along with total bacteria count. Similar consideration of water samples from Umuahia town indicated prevalence of coliform bacteria in 60% of the samples, while lead appeared in 30%. The imminent risk of cadmium, mercury and lead pollution in urban water sources in Awka, and lead in Umuahia, can be linked to anthropogenic sources, since evidence of related mineralization is historically and geologically lacking in the areas. The same trend has been associated with prevalence of microbial pollution in the surface water and shallow groundwater sources. Location of the largest and most functional abattoir (slaughterhouse) in densely populated urban centers, in addition to several other sources of organic wastes (as observed in the study areas) has great potentials to generate microbial pollutants and contaminants. Cases of using gully erosion sites (bad lands) as waste dump sites, without due consideration to the hydrologic properties of the sub-soil, enhance hydrodynamic dispersion of waste in aqueous medium. Indiscriminate location of small scale industries, mechanic workshops, garages, automobile lubrication centers, and markets, in state capitals constitutes a major source of point and distributed sources of pollution and contamination in urban water sources. All these are hinged on unplanned, or poorly planned, urbanization programmes. CONCLUSION: Closing the gap between the government and the governed, as well as the link between the ranks and files of the governing class, can assist immensely in effective programme implementation, especially in the areas of environmental protection. Modernized multi-disciplinary approach principle shall be adopted in handling the enormous task of town planning in developing countries (such as Nigeria), in line with the global best practices. Todd(1980) observed that natural environment can easily adjust and remain in harmony with with natural pollution factors, but anthropogenic pollution incidents are usually violent, and the environment needs to be regularly monitored to establish the magnitude of the damage done. Periodic evaluation of the state of water health of public water supply sources is thus a necessary priority for sustainable development, especially in heterogeneously populated urban areas witnessed in Nigeria. Silva and Dube (2013) observed that indicators expressing water quality, quantity and availability are valuable tools to evaluate and communicate the state of water health. The prevalence of some metals with proven lethal consequences in some public water sources in the study areas (irrespective of the current concentration level) needs be of great concern to all stakeholders in water governance. REFERENCES. American Public Health Association (1992).Standard methods for examination of water: 18th Edition, American Public Health Association; American Water Works Association, Washington D.C. 50-54. Leb, C.(2012 a* ) The right to water in a transboundary context: emergence of seminal trends. Water International; 37(6), 640-653. Silva, G.da Costa and M.G. Dube, (2013). Water quality assessment at a global scale: a comparison between world regions. Water International. 38 (1) , 78-94. Todd, D.K, (1980). Groundwater Hydrology, 3rd Edition, John Wiley and Sons Inc, New York. 267-315 World Health Organization, (2004): Guidelines for drinking water quality, Vol.1.World Health Organization, Geneva, 130-185
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