Из этого сделать вопросы: 1. the quality of natural water depends upon its content of impurities. 2. the result is expressed in parts per million by weight, and its includes suspended, colloidal and dissolved solids. 3. the concentration of suspended matter in water is measured by its turbidity or by the suspended-solids analysis. 4. the total amount of solid impurities in a water is
obtained by the total solids test, in which a sample of unfiltered water is evaporated and the residue weighed.