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Consumer Factsheet on: NITRATES/NITRITES
List of
Contaminants
As part of the Drinking Water and Health pages, this fact
sheet is part of a larger publication: National Primary Drinking Water
Regulations
This is a factsheet about a chemical that may be found in some public or
private drinking water supplies. It may cause health problems if found in
amounts greater than the health standard set by the United States Environmental
Protection Agency (EPA).
What are Nitrates/Nitrites and how are they used?
Nitrates and nitrites are nitrogen-oxygen chemical units which combines with
various organic and inorganic compounds. Once taken into the body, nitrates are
converted into nitrites. The greatest use of nitrates is as a fertilizer.
Why are Nitrates/Nitrites being regulated?
In 1974, Congress passed the Safe Drinking Water Act. This law requires EPA
to determine safe levels of chemicals in drinking water which do or may cause
health problems. These non-enforceable levels, based solely on possible health
risks and exposure, are called Maximum Contaminant Level Goals.
The MCLG for nitrates has been set at 10 parts per million (ppm), and for
nitrites at 1 ppm, because EPA believes this level of protection would not
cause any of the potential health problems described below.
Based on this MCLG, EPA has set an enforceable standard called a Maximum
Contaminant Level (MCL). MCLs are set as close to the MCLGs as possible,
considering the ability of public water systems to detect and remove
contaminants using suitable treatment technologies.
The MCL for nitrates has been set at 10 ppm, and for nitrites at 1 ppm,
because EPA believes, given present technology and resources, this is the
lowest level to which water systems can reasonably be required to remove this
contaminant should it occur in drinking water.
These drinking water standards and the regulations for ensuring these
standards are met, are called National Primary Drinking Water Regulations. All
public water supplies must abide by these regulations.
What are the health effects?
Short-term: Excessive levels of nitrate in drinking water have caused
serious illness and sometimes death. The serious illness in infants is due to
the conversion of nitrate to nitrite by the body, which can interfere with the
oxygen-carrying capacity of the childs blood. This can be an acute condition in
which health deteriorates rapidly over a period of days. Symptoms include
shortness of breath and blueness of the skin.
Long-term: Nitrates and nitrites have the potential to cause the following
effects from a lifetime exposure at levels above the MCL: diuresis, increased
starchy deposits and hemorrhaging of the spleen.
How much Nitrates/Nitrites are produced and released to the
environment?
Most nitrogenous materials in natural waters tend to be converted to
nitrate, so all sources of combined nitrogen, particularly organic nitrogen and
ammonia, should be considered as potential nitrate sources. Primary sources of
organic nitrates include human sewage and livestock manure, especially from
feedlots.
The primary inorganic nitrates which may contaminate drinking water are
potassium nitrate and ammonium nitrate both of which are widely used as
fertilizers.
According to the Toxics Release Inventory, releases to water and land
totaled over 112 million pounds from 1991 through 1993. The largest releases of
inorganic nitrates occurred in Georgia and California.
What happens to Nitrates/Nitrites when they are released to the
environment?
Since they are very soluble and do not bind to soils, nitrates have a high
potential to migrate to ground water. Because they do not evaporate,
nitrates/nitrites are likely to remain in water until consumed by plants or
other organisms.
How will Nitrates/Nitrites be detected in and removed from my drinking
water?
The regulation for nitrates/nitrites became effective in 1992. Between 1993
and 1995, EPA required your water supplier to collect water samples at least
once a year and analyze tem to find out if nitrates/nitrites are present above
50 percent of their MCLs. If it is present above this level, the system must
continue to monitor this contaminant every 3 months.
If contaminant levels are found to be consistently above their MCLs, your
water supplier must take steps to reduce the amount of nitrates/nitrites so
that they are consistently below that level. The following treatment methods
have been approved by EPA for removing nitrates/nitrites: Ion exchange, Reverse
Osmosis, Electrodialysis.
How will I know if Nitrates/Nitrites are in my drinking water?
If the levels of nitrates/nitrites exceed their MCLs, the system must notify
the public via newspapers, radio, TV and other means. Additional actions, such
as providing alternative drinking water supplies, may be required to prevent
serious risks to public health.
Drinking Water Standards (ppm): MCLG MCL
Nitrate: |
10 |
10 |
Nitrite: |
1 |
1 |
Nitrate and Nitrite Releases to Water and Land: 1991 to 1993 (in
pounds)
|
Water |
Land |
TOTALS |
59,014,378 |
53,134,805 |
|
Top Fifteen States*
| |
GA |
12,114,253 |
12,028,585
|
CA |
0 |
21,840,999
|
AL |
3,463,097 |
6,014,674
|
LA |
8,778,237 |
2,250
|
MO |
6,985,890 |
206,181
|
MS |
6,952,387 |
0
|
KS |
5,140,000 |
877,095
|
VA |
5,091,764 0
|
NV |
0 |
4,977,482
|
FL |
1,056,560 |
1,835,736
|
AR |
1,206,610 |
1,058,294
|
MD |
1,802,219 |
138,819
|
IA |
1,500,340 |
132,042
|
OK |
1,436,348 |
14,199
|
UT |
0 |
1,045,400
|
|
Major Industries*
| |
Nitrogenous fertilizer |
41,584,611 |
8,607,376
|
Misc. Ind. inorganics |
4,113,312 |
29,676,919
|
Misc. Metal ores |
0 |
5,764,976
|
Misc. Ind. organics |
5,091,764 |
0
|
Fertilizer mixing |
480,000 |
4,554,916
|
Explosives |
850,921 |
1,297,590
|
Paper mills |
1,727,061 |
0
|
Pulp mills |
1,321,500 |
3,350
|
Canned foods |
0 |
1,056,794
|
Phosphate fertilizers |
1,000,000 |
0
|
* State/Industry totals only include facilities with releases greater than
10,000 lbs.
Learn more about your drinking water!
EPA strongly encourages people to learn more about their drinking water, and
to support local efforts to protect and upgrade the supply of safe drinking
water. Your water bill or telephone books government listings are a good
starting point.
Your local water supplier can give you a list of the chemicals they test for
in your water, as well as how your water is treated.
Your state Department of Health/Environment is also a valuable source of
information.
For help in locating these agencies or for information on drinking water in
general, call: EPAs Safe Drinking Water Hotline: (800) 426-4791.
For additional information on the uses and releases of chemicals in your
state, contact the: Community Right-to-Know Hotline: (800) 424-9346.
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