Drinking water normally supplies only about 1% of one’s
dally nitrate intake; vegetables provide most of the rest. But some waters, usually from private wells
in rural areas, contain many times the normal concentration. The EPA nitrate standard is 10 parts per
High nitrate levels usually stem from agricultural
activities. Chemical fertilizers and
manure from animal feed lots are particularly rich sources of nitrogen
compounds, which are converted to nitrates in the soil. Wastes leaking from septic tanks also add
nitrate to groundwater.
Babies less than six months old may become seriously ill
from drinking water high in nitrate.
The main threat to infants arises from formula mixed with nitrate-rich
water. Bacteria in infants' digestive
tracts convert the relatively harmless nitrate to nitrite. Nitrite in turn
combines with some of the hemoglobin in the blood to form a compound called
methemoglobin, which cannot transport oxygen.
The resulting condition, methemoglobinemia, deprives vital organs of
High nitrate levels may signal that other contaminants such
as agricultural pesticides or bacteria and viruses from septic tanks are also
present. Some state health departments
test private wells free.
reverse-osmosis units remove nitrate.
Digging a deeper well to an uncontaminated water source is another