Rain Water Characterization at Urban and Rural (North B) Unguja

Abstract

Aim of the study was to assess the physicochemical characteristics of rainwater at urban and rural (north B) Unguja. Twenty four (24) rainwater samples were analyzed for pH, electrical conductivity (EC) and total dissolved solids (TDS) and cations: calcium (Ca2+), copper (Cu2+), iron (Fe2+), chromium (Cr VI) , and anions: fluoride (F-), nitrite and sulfate (SO42-). The investigated physicochemical parameters in the rainwater samples were within the permissible limits of the World Health Organization (WHO) drinking water quality guidelines. The ranges of concentration for the physical parameters analyzed were; pH: (5.8 – 7.7), EC: (5.08 – 35.6 µS/cm), TDS: (1.68 – 20.16 mg/L, Ca: (0.163 – 24.331 mg/L), Cr: (VI) : (BDL – 0.029 mg/L), Cu: (BDL - 0.085 mg/L); Fe: (BDL – 0.068), anions were SO42- : (BDL – 5.00 mg/L) and F- : (BDL – 0.5 mg/L). Nevertheless, there was no significant difference for the measured parameters between urban and rural areas. This is a good indication that the air quality in Zanzibar is remarkably not polluted with respect to the parameters studied.