|Title:||POTENTIAL SOURCES OF HEAVY METAL POLLUTION IN DRINKING WATER OF ADDIS ABABA.|
|Abstract:||The level of lead (Pb) in the world’s environment has generally increased since industrialization. Although the consumption of lead in developed countries has been declined, it is still being used in developing countries. The new specification that was brought into law in early 2003 provides for both regular and premium gasoline and leaded and unleaded types. Before this new specification, there was the use of leaded gasoline in Ethiopia (Addis Ababa) for many years in the past. The massive scale of human lead mining and consumption has led to substantial amounts of lead (Pb) being released in to the environment and furthermore being transported by environmental means through water, air and soil. Once the initial deposition of Pb into the environment has taken place, it may be transferred between water, soil and air and thus continue its long-range environmental transport contaminating the environment. Lead can enter into water bodies through air, soil and direct discharge from point sources. This study was aimed to investigate the potential sources of contamination of drinking water by Lead in Addis Ababa. It was specially aimed at the determination of the concentration of lead (Pb) and additionally those of Chromium and cadmium in soils around Legedadi and Gefersa dams, and Akaki ground water sources and the extent of their pollution in the drinking water of Addis Ababa using AAS. For the analysis, known mass of dried soil samples were digested using wet digestion method in 1.5 mL (30%) H2O2 and 6 mL of freshly prepared 3:1(v/v) mixture of conc.HCl and conc.HNO3 (aqua regia) for three and half an hour in temperature interval from 180 – 240 0C. The concentrations of Pb, Cr and Cd were analyzed using Atomic Absorption Spectrophotometer and the pH of the soil samples was also measured. From analysis of the soil samples, the ranges of mean concentrations (mg/kg) of lead ,chromium and cadmium and pH ranges of the soils collected around the four sites; Dire, Legedadi, Akaki and Gefersa respectively are 33.00 – 59.70, 35.40 – 68.60, 35.80 – 468.70 and 36.60 – 67.30 for Pb ; 17.70 – 34.40, 21.20 – 37.50, 43.00 – 988.00 and viii 33.70 – 88.60 for Cr ; 2.30 – 3.40, 2.10 – 5.50, 2.90 – 6.60 and 2.30 – 3.90 for Cd and the pH ranges are 5.40 – 5.86, 5.63 – 8.07, 6.53 – 8.49 and 4.82 – 5.82. The ranges of mean concentrations (mg/kg), mean concentrations of Pb, Cr and Cd and pH ranges of the soil samples collected in the four sampling locations of the sources of Addis Ababa drinking water respectively are ; 33.0 ± 1.6 – 469 ± 6.9, 17.7 ± 0.6 – 988 ± 64.0 and 2.1 ± 0.1 – 6.6 ± 0.5 and 4.82 ± 0.04 – 8.49 ± 0.15.|
|Description:||A Thesis Submitted to the School of Graduate Studies of Adds Ababa University in Partial Fulfillment of the Degree of Master of Science in Environmental Science|
|Appears in Collections:||Thesis - Environmental Science|
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