To
show that tap water contains
fine
dust particles throught it appears to
be clean
Answers
Explanation:
In addition to dissolved substances, drinking water typically contains small amounts of very finely divided solid particles of several kinds. These particles, ranging in size from colloidal dimensions to about 100 µm, are composed of inorganic and organic materials that are derived from soils and rocks and from the debris of human activity with which the raw water has come in contact. They include clays, acicular or fibrous particles of asbestos minerals, and organic particles resulting from the decomposition of plant and animal debris in the soil.
Little is known about the effects that these suspended solids may have on the health of those who drink water that contains them. However, there is widespread concern over the biological effects of the asbestos mineral fibers that occur in water, since similar fibers are known to be carcinogenic when air heavily laden with them is inhaled for many years. In view of this concern that such fibers as occur in water may be injurious to health, their occurrence, characterization, analysis, and biological effects are reviewed in some detail.
No evidence has yet been discovered that either of the other classes of common particulate contaminants of drinking water—clays and organic colloids—has any direct effect on health. Nevertheless, it is possible that both may indirectly affect the quality of drinking water because they can adsorb a variety of toxic substances, bacteria, and viruses from solution or suspension and bind them more or less strongly. By such means these materials may serve to concentrate and transport some water pollutants and protect them from removal by water treatment.
For this reason, the properties of days and organic particulates are also discussed, together with the tendency of chemicals, bacteria, and viruses to become concentrated at the surfaces of such particles.
Removal of suspended particles from water is briefly reviewed, together with the significance of measurements of turbidity as an index of water quality.