title: Drinking water quality in the Ethiopian section of the East African Rift Valley I--data and health aspects.
abstract: Drinking water samples were collected throughout the Ethiopian part of the Rift Valley, separated into water drawn from deep wells (deeper than 60 m), shallow wells (<60 m deep), hot springs (T>36 degrees C), springs (T<32 degrees C) and rivers. A total of 138 samples were analysed for 70 parameters (Ag, Al, As, B, Ba, Be, Bi, Br, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Dy, Er, Eu, F, Fe, Ga, Gd, Ge, Hf, Hg, Ho, I, In, K, La, Li, Lu, Mg, Mn, Mo, Na, Nb, Nd, Ni, NO(2), NO(3), Pb, Pr, Rb, Sb, Se, Si, Sm, Sn, SO(4), Sr, Ta, Tb, Te, Th, Ti, Tl, Tm, U, V, W, Y, Yb, Zn, Zr, temperature, pH, conductivity and alkalinity) with ion chromatography (anions), spectrometry (ICP-OES and ICP-MS, cations) and parameter-specific (e.g. titration) techniques. In terms of European water directives and WHO guidelines, 86% of all wells yield water that fails to pass the quality standards set for drinking water. The most problematic element is fluoride (F), for which 33% of all samples returned values above 1.5 mg/l and up to 11.6 mg/l. The incidence of dental and skeletal fluorosis is well documented in the Rift Valley. Another problematic element may be uranium (U)-47% of all wells yield water with concentrations above the newly suggested WHO maximum acceptable concentration (MAC) of 2 microg/l. Fortunately, only 7% of the collected samples are above the 10 microg/l EU-MAC for As in drinking water.
authors.affiliation: Geological Survey of Norway, N-7491 Trondheim, Norway. clemens.reimann@ngu.no
authors.forename: Clemens
authors.initials: C
authors.lastname: Reimann
authors.forename: Kjell
authors.initials: K
authors.lastname: Bjorvatn
authors.forename: Bjørn
authors.initials: B
authors.lastname: Frengstad
authors.forename: Zenebe
authors.initials: Z
authors.lastname: Melaku
authors.forename: Redda
authors.initials: R
authors.lastname: Tekle-Haimanot
authors.forename: Ulrich
authors.initials: U
authors.lastname: Siewers
mesh_terms: D005002:Ethiopia; D005459:Fluorides / Q000032:analysis*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D011634:Public Health; D012016:Reference Values; D018570:Risk Assessment; D013696:Temperature; D014867:Water / Q000737:chemistry*; D014873:Water Pollutants / Q000032:analysis*; D014881:Water Supply
chemical_list: D014873:Water Pollutants; D014867:Water; D005459:Fluorides