Nitrate, Nitrite, and Orthophosphate
Nitrate, nitrite, and orthophosphate may be present due to runoff from heavily fertilized areas, septic contamination, animal/waterfowl waste, or decomposing vegetative material.
Nitrate levels in excess of 10 mg/L and nitrite levels in excess of 1 mg/L are considered excessive, especially for infants.
Short term, excessive levels of nitrate have caused serious illness and even death. Infants below the age of six months who drink water containing nitrate and nitrite in excess of the MCL could become seriously ill. Symptoms include shortness of breath and blueness of the skin.
Nitrate, nitrite, and orthophosphate can be removed from water by reverse-osmosis filtration.