Role of Laboratory Tests and Ultrasound in Detection of the Dangers of Total Dissolved Solids in Drinking-Water

One of the primary goals of WHO and its member states is that all people, whatever their stage of development and their social and economic conditions, have the right to have access to an adequate supply of safe drinking water Total dissolved solids (TDS) is the term used to describe the inorganic salts and small amounts of organic matter present in solution in water. The principal constituents are usually calcium, magnesium, sodium, and potassium cations and carbonate, hydrogencarbonate, chloride, sulfate, and nitrate anions The method of determining TDS in water supplies most commonly used is the measurement of specific conductivity with a conductivity probe that detects the presence of ions in water. Conductivity measurements are converted into TDS values by means of a factor that varies with the type of water (1, 2). The practical quantitation limit for TDS in water by this method is 10 mg/litre (M. Forbes, personal communication, 1988). High TDS concentrations can also be measured gravimetrically, although volatile organic compounds are lost by this method (3). The constituents of TDS can also be measured individually. the main source of drinking water in Saudi Arabia. (4). TDS in water supplies originate from natural sources, sewage, urban and agricultural run-off, and industrial wastewater. Salts used for road de-icing can also contribute to the TDS loading of water supplies. Concentrations of TDS from natural sources have been found to vary from less than 30 mg/litre to as much as 6000 mg/litre (5)