The concentration of nitrate can be expressed either in terms of the nitrate ion or in terms of the principal element, nitrogen. The mass of the nitrogen atom is 14. The ratio of the nitrate ion mass to the nitrogen atom mass is 4.43. When dealing with nitrate numbers it is very important to know how numeric values are expressed. For purposes of drinking water regulations, standards are expressed in the form of the principal element.
Bacteria are small, one-celled animals too small to be seen by the naked eye.
Bacteria are found everywhere, including on and in the human body. Humans would be unable to live without the bacteria that inhabit the intestines and assist in digesting food. Only a small percentage of bacteria cause disease in normal, healthy humans. Other bacteria can cause infections if they get into a cut or wound. Chlorine is a chemical used to disinfect water.