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Title: Assessment of the Status of Nitrate Pollution in Selected Water Sources in Addis Ababa
???metadata.dc.contributor.*???: Prof. Tenalem Ayenew
Girma, Hailu
Keywords: nitrate pollution;Addis Ababa
Issue Date: Jul-2011
Publisher: aau
Abstract: This study was conducted to assess the status of nitrate pollution in selected water sources in Addis Ababa with the objective of understanding the extent and mechanism of nitrate pollution and to map the distribution in the study area. 28 primary and 75 secondary data from 89 sites were used. Standard method for the examination of water and waste water (APHA, 2005) had been used for laboratory analyses. NO3 -, NO2 -, and PO4 3- were analyzed by UVSpectrophotometer, HACH DR-4000 and Cl- was determined by mercuric nitrate method along with in-situ measured physico-chemical variables like pH, total dissolved solids, electrical conductivity, and temperature . Then, by taking nitrate as important parameter primary and secondary data were analyzed with SPSS and MS-Excel spread sheet. The results showed that the mean and standard deviation of nitrate and nitrite concentrations (mg/L-1) in water samples were 52.03 + 40.16 and 0.03 + 0.01 respectively. Samples from 9 sites (Coca Cola well , Ras Mekonen spring, Tsebay Maremiya well, Anwar Mosque well, Africa Hotel well, Lideta spring, Mekanisa Abo spring, Abunearegawi spring and Ras Hotel well ) are found contaminated and had more than the maximum acceptable concentration (MAC) of nitrate. The distribution and extent of NO3 - is mapped based on the result and showed the central part of the city had higher concentration from 58 to 102mg/L-1 whereas the upper part of the city had lower concentration 0.1 to 6.6mg/L-1. Since high concentration of nitrate is a public health concern especially for infants under the age of six months which causes methemoglobinemia (blue-baby syndrome) the analyses result in the central sites revealed that the water is unsafe from nitrate and nitrite pollution points of view. Pearson’s paired samples analysis showed positive correlation b/n NO3 - and Cl- at a significant level of 0.01(99%) with a regression equation (Cl- = 0.868 NO3 - + 11.276 ;R2 = 6.288) suggesting that the pollution of both NO3 - and Cl- might be due to the similar sources like seepage of pit latrines and infiltration of polluted effluents. A management option is very essential and it is necessary to apply some actions to reduce/remove nitrate from drinking water sources by either abandoning the sources or by applying treatment methods like ionexchange, reverse osmosis, and distillation as possible as at a lower and effective cost. It is concluded that water resources should not be at a closer distances to pit latrines and polluted discharges.
Description: A Thesis submitted to the school of Graduate Studies of Addis Ababa University in partial fulfillment of the requirements for the degree of Master of Sciences in Environmental Science
Appears in Collections:Thesis - Environmental Science

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