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FACT SHEET ON A DRINKING WATER CHEMICAL CONTAMINANT
GENERAL INFORMATION
Synonyms
•	Potassium Nitrate; Saltpeter
Chemical Description:
» Naturally occurring inorganic ions which make
up part of the nitrogen cycle
Properties:
•	Nitrate ion is the stable form of combined
nitrogen in oxygenated water
•	Nitrite, the reduced form of nitrate, is relatively
unstable and reactive, and tends to be
converted to nitrate
•	Highly soluble in water
•	Non-volatile
Production and Use:
•	Nitrate is used primarily as an inorganic fertilizer
ENVIRONMENTAL PROFILE
Occurrence:
•	Nitrate occurs naturally in food (e.g. spinach,
beets, etc.)
» Nitrate predominates in ground and surface
waters
•	Surface waters generally contain lower levels
of nitrate and nitrite than ground wafers
« EPA estimates that 1.2% of Community Water
System (CWS) wells and 2.4% of rural domestic
wells nationally contain concentrations that
exceed EPA s Maximum Contaminant Level
(MCI) for Total Nitrate/Nitrite (as N)
Releases:
•	Enters wafer and soil through runoff from fields
treated with nitrogen fertilizer, animal manure,
septic tank wastes, and sewage sludge
Environmental Fate:
•	Due to its high solubility and weak retention by
soil, it is highly mobile in soil (moving at
approximately the same rate as water through
the soil), and has a high potential to migrate
to ground water
•	Because it does not volatilize, once it enters
water, it is likely to remain there untff used by «
plants or other organisms
HEALTH EFFECTS
Humans:
» Toxicity of nitrate is due to its reduction to
nitrite in the saliva of humans; by reacting with
hemoglobin, nitrite forms methemoglobm.
which will not transport oxygen to the tissues
and thus can lead to asphyxia
*	Infants 6 months old or less, particularly those
who are bottle fed, are sensitive to nitrate,
possibly because the decreased acidity in their
stomachs enables bacteria capable of
reducing nitrate to nitrite to proliferate
Experimental Animals:
•	Effects of acute exposure to high levels of
nitrate/nitrite: cardiovascular collapse and
shock, and elevated methemoglobm levels
*	Effects of chronic exposure to high levels of
nitrate/nitrite: diuresis, increased starchy
deposits, and hemorrhaging of the soieen
•	Inconclusive studies on mutagenic and
carcinogenic potential of nitrate/nitrite
REGULATORY HISTORY
Existing Standards:
•Clean Air Act (CAA): Not regulated
•Clean Water Act (CWA):
Criteria established
'Resource Conservation and Recovery Act
(RCRA):
¦ Not regulated
•Superfund (CERCLA):
•Not regulated
•SARA: Title III, Section 313
•Federal Insecticide, Fungicide, and
Rodenttcide Act (FIFRA):
Not registered
•Toxic Substances Control Act (TSCA):
Regulated

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HEALTH INFORMATION
Maximum Contaminant L«vei Goal* (MCLG):
•	Non-enforceable levels based solely on an
evaluation of possible health risks and
exposure, and taking into consideration a
margin for public safety
•	Set at 10 mg/L (as N) to protect .against
methemoglobinemia
MCLG for Nitrate (a* N) = 10 mg/L
MCLG for Nitrite {as N) = 1 mg/L
MCLG for Nitrate - Nitrite (at N) = 10 mg/L
(all values effective July 1992)
Maximum Contaminant Levels (MCL):
» legally enforceable levels for contaminants in
public drinking water supplies
•	Based on health risks associated with the
contaminants, analytical methods for their
assay, and water treatment feasibility and
practicality aspects
« Exceedance of the MCL in drinking water may
result in adverse effects which will depend
upon the contaminant concentration in water,
amount of water/contaminant ingested,
length of exposure, and other biological
parameters
•	Current MCI for Nitrate (as N) = 10 mg/L
MCL for Nitrate (as N) = 10 mg/L
MCL for Nitrite (as N) = 1 mg/L
MCL for Nitrate * Nitrite (as N) = 10 mg/L
(all values effective July 1992)
EPA Health Advisories (HA):
•	Short-term HAs: Provide acceptable
concentrations of contaminants in wafer for
up to 10 day exposures, primarily to evaluate
the public health risk resulting from an
accidental spill or an emergency
contamination situation
« Longer-term HAs: Provide guidance for
persistent water contamination situations to
cover a period of up to 7 years
•	Lifetime HAs: Derived in the same way as an
MCLG
Hectth Advisories;
(HA levels currently under IPA review)
ANALYTICAL METHODS '
Nitrate:
•	Manual Cadmium Reduction:
EPA Method 353.3
» Automated Hydrazine Reduction:
EPA Method 353.1
•	Automated Cadmium ^ecuc cr
EPA Method 353.2
•	ion Selective Electrode:
WeWWG/5880
•	Ion Chromatography:
EPA Methoa 300.0
ilfinifuiL
Ntime:
•	Automated Cadmium Reduction:
EPA Method 353.1
•	Manual Cadmium Reduction:
EPA Method 353.2
« Ion Chromatography:
EPA Method 300.0
•	Spectrophotometry:
EPA Method 354.1
TREATMENT OPTIONS
Permanent Treatment;
•	Best Available Technology (BAT):
Nitrate;
•Ion Exchange
•Reverse Osmosis
•Electrodialysis Reversal
Nitrite;
•Ion Exchange
• Reverse Osmosis
SHORT-TERM HAZARD ELIMINATION
•	If the drinking wafer standards are exceeded,
install BAT or use an alternative drinking wafer
supply such as bottled water
ADDITIONAL HELP
•	Stat© or county health officials can indicate a
certified laboratory for testing
« Experts in the state Department of
Environmental Protection, Natural Resources, or
Agriculture may also be of help
« The EPA has toll-free numbers for further
information on drinking water quality
treatment technologies, for obtaining Heaim
Advisories, and for other regulatory information
•	EPA Hotlines are available Monday througn
Friday
•Safe Drinking Water	800-426-4791
•National Pesticides:	800-858-7378
•Superfund/RCRA:	800-424-9346
•	For information on the Clean Water Ac' cat!
(202) 260-7301
•	For information an the Toxic Substances
Control Act, call (202) 554-1404
•	For information on the Clean Air Act. ca:
(919) 541-27771

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