The purpose of this Ph.D. research work aims to investigate the major ions chemistry and chemical type classification of the Eastern Tanzania Rift Valley Soda- saline lakes. The specific objectives of the proposed research works are (1) To determine the major ion chemistry of Eastern Tanzania rift valley soda-saline lake, (2)To assess temporal variations of the ion chemistry of Eastern Tanzania rift valley soda-saline lake, (3) To classify Eastern Tanzania rift valley soda-saline lake into their respective water types, (4) To analyze the spatial geographical distribution of the identified chemical types relative to hydrological conditions (hydrogeological origin, water balance, sources, the structure of watershed, etc.), and (5)To assess the physical and chemical properties of the soil around the premises of the identified soda-saline water chemical type. The pH and electrical conductivity of the water samples will be determined by pH meter and Portable conductivity meter respectively. The Major cations (Na⁺, K⁺, Ca²⁺, Mg²⁺,) will be determined by an Inductively coupled plasma optical emission spectrometer (ICP-MS). Major anions (Cl^-, SO₄^2-) will be determined by ion chromatography, and (HCO₃^-, CO₃^2-) will be determined by the Titration method with methyl red/bromocresol and phenolphthalein indicators respectively. The classification criterion proposed by (Boros & Kolpakova, 2018) will be used to classify the water chemical type of the Eastern Rift Valley Soda-saline lakes. At the end of the research work, the following outcomes are expected (1)To update the major ions chemistry information for the Eastern Tanzania rift valley soda-saline lake (2) classification of the water chemical type for the Eastern Tanzania rift valley soda-saline lake (3) To develop the database for the spatial distribution of the identified water chemical type, and (4)To classify the soil type based on the concentration of the physical and chemical of the soil. This ongoing research work is funded by the StipendiumHungaricum scholarship.