Asia awareness. Cl and F-

E. coli, dysentery, and typhoid infection resulting from wastewater entering freshwater.

Filtration aids in keeping solid waste out of freshwater.  And chlorine (Cl) chemical treatment of drinking water can kill e. coli and other bugs at effective level amounts, not to exceed–go beyond safe levels of usage (into toxic levels of concentration that are unacceptable concentration levels of Cl in drinking water).

Flouride (F-) strengthens teeth, reduces cavities–cavities common from sugar intake and beefeaters, and other animals, poultry and fish served as food.  Dangers exist in handling preparing drinking water correctly. Use correct procedure and equipment and worker business clothes.

Anything in large doses for a single person can be bad, or terrible.