Manganese is also an essential nutrient for humans at approximately 5 mg per day. Some sodium is found in all natural water supplies, but more so in areas where seawater and road salt seep into the ground. Sodium has no set hazard level, but those individuals on a low sodium diet should take into account the amount of sodium in their water when determining overall sodium intake. Chloride is associated with infiltration of road salt, fertilizer, backwash from a water softener and even seawater. The presence of nitrate and nitrite generally indicates contamination from a pasture, manure pile, decomposed vegetation or fertilized agricultural land.
Nitrates change to nitrites in the body, which reduces oxygen uptake by the hemoglobin.
Boiling the water will not help, it will only concentrate the nitrates. Recommended adult intake of fluoride is 1.0 - 2.5 mg per day. Children are often given a supplement if their home drinking water is not sufficient. The high copper concentrations in New Hampshire are almost always a result of corrosive water picking up copper from plumbing lines. L Chronic ingestion of lead has been associated with a large number of harmful health effects, and therefore water with excessive lead levels should not be consumed.