ARSENIC AND FLUORIDE IN THE GROUNDWATERS OF TANZANIA

Groundwater resources are becoming the major source of portable water for domestic, industrial and irrigation use in many parts of the globe. However, targeting safer aquifer remains uncertain among drillers and local users. In Tanzania, apart from efforts made by the government to bring close clean water to her citizens, 40% of these drinking water sources are not functional due to various reasons such natural dry up, elevated salinity and fluoride. In addition, about 11% of the present drinking water sources contain considerable amounts of dissolved substances that render water to be turbid. The present study focuses on quantifying and assessing the spatial distribution of physiochemical parameters of water such as , temperature, pH, electric conductivity (EC), alkalinity, Chloride (Cl^-), Nitrate (NO₃^-),nitrite (NO₂ ), total solids (TS), total suspended solids (TSS), total dissolved solids (TDS), total hardness (sodium (Na⁺) and potassium (K⁺)), sulphate (SO₄^2-), phosphate(PO₄^3-), fluoride (F^-), arsenic (As), water cover/spread, oxygen (O₂), carbon dioxide (CO₂), and water quality index (WQI). Geostatistical models are developed and used to assess the spatial autocorrelation of As and F in relation to the rest of the remaining parameters. This approach is very useful especially when there is scarce spatial data due limited funds to sample a every location in the country.