The contamination of water is directly related to the degree of contamination of our environment. Rainwater flushes airborne pollution from the skies, and then washes over the land before running into the, rivers, aquifers, and lakes that supply our drinking water. Any and all chemicals generated by human activity can and will find their way into water supplies. Chlorine belongs to the group of elements called halogens. The halogens combine with metals to form compounds called halides.
Chlorine is manufactured commercially by running an electric current through salt water.
This process produces free chlorine, hydrogen, and sodium hydroxide. Chlorine is changed to its liquid form by compressing the gas, the resulting liquid is then shipped. Liquid chlorine is mixed into drinking water and swimming pools to destroy bacteria. Until recently, concerns about drinking water focused on eliminating pathogens. The chlorine used to reduce the risk of infectious disease may account for a substantial portion of the cancer risk associated with drinking water.