The primary use of iodine with water is for the purification of drinking water. Iodine is a disinfectant is may be dissolved in water. Iodine tablets are can be added to water for disinfection purposes. Iodine is used for cleansing and disinfecting wounds and is added to some soaps. It also plays an important role in the production of thyroid hormones.
As sodium dissolves in water, a colorless solution of sodium hydroxide and hydrogen gas is formed. Sodium is partially responsible for the body's nerve functions and it regulates cellular fluids. Drinking water contains 50 mg of sodium per liter. Sodium shortages can lead to dehydration, muscle paralysis and convulsions. An overdose of sodium can cause high blood pressure, confusion and infection risks.
Bromine is used to disinfect swimming pool and cooling tower water, not drinking water. Bromine is a bleach that is poisonous, and its vapor is destructive for human eyes, skin and respiratory tracts. Bromine is produced by sea organisms and can be found in salt form. It can dissolve easily in water.
Nitrogen leads to water quality problems and a decline in wildlife and wildlife habitat. Excessive levels of nitrates in drinking water have caused serious illness and sometimes death. Nitrogen is a fertilizer and when used can seep into nearby lakes and streams. Dead fish and green water are nitrogen indicators.