Investigation of physico-chemical Characteristics and Heavy Metals Concentration Implying to the Effect of Local Geology on Surface Water Quality of Werii Catchment, Tigray, Ethiopia

Abstract

The paper assesses the water quality parameters of Werii catchment in Northern Ethiopia. 27 water samples were collected and analyzed for 17 physico-chemical parameters. The electrical conductivity ranges 128-627μS/cm, while turbidity: 20-36.23NTU; total dissolved solids: 140.5-389 mg/L, and total alkalinity: 105-510 mg/L. The proportion of the samples exceeding WHO guidelines for drinking purposes in increasing order are Cu (16%), Cr (40%), As (44%), Ni (54%), Pb (64%), Fe (76%), Co (80%) and Zn (100%). One-sample testing confirmed that all but Fe significantly exceed the WHO guidelines values. The result of both One-way ANOVA and Factor analyses revealed Cr, Zn, Cu and Turbidity are associated with Werii slates in the first of five factors. Fe, As, Ni and Co are associated with Tsedia Slate in the second factor. The rest factors indicated that EC, TS, TSS and Co are attributed to Aiba basalt, Adigrat sandstone, Werii Slates and Tsedia Slates respectively.

Keywords

• heavy-metals
• surface water quality
• factor analysis
• lithounits