United States
Environmental Protection
Agency
Office of Water
4601
EPA811-F-95-002I- T
October 1995
National Primary Drinking
Water Regulations
Cyanide
CHEMICAL/ PHYSICAL PROPERTIES
CAS NUMBER: Hydrogen cyanide- 74-90-8
COLOR/ FORM/ODOR: Cyanide is a carbon-nitrogen chemical unit
which may be combined with a variety of organic and.
inorganic components. The most common is hydrogen •
cyanide, a colorless, flammable liquid or gas.
SOIL SORPTION COEFRCIENT: Kocs of 1 to 70 for most soluble forms,
with the nitriles having highest mobility in soils. Insoluble
forms are expected to adsorb to sediments.
CYANIDE-CONTAINING COMPOUNDS:
Organics: Nitriles like Acetonitrile, butanenitrile, etc; bromoxynil,
cyanocobalamin, cyanogens, cyanohydrins, tabun
Inorganics: combined with hydrogen, calcium, barium, sodium,
zinc, nickel, mercury, potassium, copper, silver
BIOCONCENTRATION FACTOR: BCFs of <1 to 50 for most soluble
forms, which are not expected to bioconcentrate in aquatic
organisms. Insoluble forms may bioconcentrate.
SOLUBILITIES:
nitriles low to moderate
cyanohydrin highly soluble
cyanogens moderate to high
tabun soluble
other organics slightly soluble
Hydrogen soluble
sodium .48% at 10 deg C
potassium . 50% in cold water
mercuric 10% at 14 deg C
barium 80% at 14 deg C
calcium soluble
copper insoluble
DRINKING WATER STANDARDS
MCLG: 0.2 mg/l
MCL: 0.2 mg/l
HAt(child): 1- to 10-day: 0.2 mg/L
Longer-term: 0.2 mg/L
HEALTH EFFECTS SUMMARY
- used in acrylic/modacrylic fibers and resins. Other
cyanides such as dichlobenil, bromoxynil and bantrol,
are used as herbicides. Tabun is used as a chemical
warfare agent. Potassium cyanide is user4 for silver
plating and for dyes and specialty products.
Available production data on cyanides: hydrogen cya-
nide, 1 billion IDS. in 1987; acrylonitrile-2.5 billion Ibs.
1993; adiponitrile-1,4 billion Ibs. in 1991; bromoxynil-2.6
Acute: EPA has found cyanide compounds to poten- mimon IDS in iyy^- ac
tially cause the following health effects from acute expo-
sures at levels above the MCL: rapid breathing, tremors
and other neurological effects.
Short-term exposures in drinking water considered
"safe" for a 10-kg (22 Ib.) child consuming one liter of
water per day: upto a 7-year exposure to 0.2 mg/L.
Chronic: Cyanide compounds have the potential to
cause the following chronic health effects from long-
term exposures at levels above the MCL: weight loss,
thyroid effects, nerve damage.
Cancer: There is inadequate evidence to state whether
or not cyanide compounds have the potential to cause
cancer from lifetime exposures in .drinking water.
USAGE PATTERNS
The most commonly used form, hydrogen cyanide, is
mainly used in manufacturing other cyanides, particu-
larly adiponitrile which is used in nylon, and acrylonitrile
etonimie-3t>
1
.
minion ID. in iy«y.
»
Toxic RELEASE INVENTORY -
RELEASES TO WATER AND LAND:
TOTALS (in pounds)
Top Ten States *
CA
PA
IN
OH
TX
MD
Major Industries*
Blast furnaces + steel
Metal heat treating .
.. Ind organic chems
Plating + polishing
Water
939,611
0
208,239
187,377
160,203
54,379
89,438 .
747.970
0,
49,098
29,486
1 987 TO 1993
Land
.641,082
430,886
4.909
20,242
850
83,394
23,503
•
.53,404
430,886
82,912
29,636
October 1995
.Technical Version
Printed on Recycled Paper
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RELEASE PATTERNS
The major sources of cyanide releases to water are
reported to be discharges from metal finishing industries,
iron and steel mills, and organic chemical industries.
Releases to soil appear to be primarily from disposal of
cyanide wastes in landfillsiiand the use of cyanide-
containing road salts. Cyanide released to air from car
exhaust is expected to exist-almost entirely as hydrogen
cyanide gas.
Some foods may also naturally contain cyanides,
including lima beans and almonds. Chlorination treat-
ment of some wastewaters can produce
chloroacetonitriles as a by-product.
Cyanide has been found in drinking water at levels on
the order of a few parts per billion.
From 1987 to 1993, according to the Toxics Release
Inventory cyanide compound releases to land and water
totalled about 1.5 million Ibs., of which about 65 percent
was to water. These releases were primarily from steel
mills and metal heat treating industries. The largest
releases occurred in California and Pennsylvania.
ENVIRONMENTAL FATE
Nitrites are generally highly volatile and biodegradable
when released to water, and are not expected to biocon-
centrate in aquatic organisms. Nitrites have the potential
to leach to ground water as they do not adsorb to soil.
They tend to be resistant to hydrolysis in soil or water.
Cyanide-containing herbicides have more moderate
potential for leaching, but again are readily biodegraded
so they are not expected to bioconcentrate.
Soluble cyanide compounds such as hydrogen and
potassium cyanide have low adsorption to soils with high
pH, high carbonate and low clay content. However, at pH
less than 9.2, most free cyanide is expected to convert to
hydrogen cyanide which is highly volatile. Soluble cya-
nides are not expected to bioconcentrate.
Insoluble cyanide compounds such as the copper, and
silver salts may adsorb to soils and sediments, and
generally have the potential to bioconcentrate. Insoluble
forms do not biodegrade to hydrogen cyanide.
Tabun is rapidly hydrolyzed in soil and water, and so is
not expected to leach or bioconcentrate.
OTHER REGULATORY INFORMATION
MONITORING:
• FOR GROUND WATER SOURCES:
- INITIAL FREQUENCY- 1 sample once every 3 years
REPEAT FREQUENCY- If no detections for 3 rounds, once every 9 years
- FOR SURFACE WATER SOURCES:
INITIAL FREQUENCY- 1 sample annually
REPEATFREQUENCY- If no detections for 3 rounds, once every 9 years
- TRIGGERS - If detect at > 0.2 mg/L, sample quarterly.
ANALYSIS:
REFERENCE SOURCE
EPA 600/4-79-020
NTIS PB 91-231498
Standard Methods
METHOD NUMBERS
335.1*; 335.2; 335.3
D2036-89A; D2036-89B*
4500-CN-D.E&.F; 4500-CN-G*
.*- measure "free" or amenable cyanide; other methods screen for "total1
cyanide.
TREATMENT
BEST AVAILABLE TECHNOLOGIES
Ion Exchange-, Reverse Osmosis, Chlorine
FOR ADDITIONAL INFORMATION:
* EPA can provide further regulatory and other general information:
• EPA Safe Drinking Water Hotline - 800/426-4791
* Other sources of lexicological and environmental fate data include:
• Toxic Substance Control Act Information Line -.202/554-1404
• Toxics Release Inventory, National Library of Medicine - 301/496-6531
• Agency for Toxic Substances and Disease Registry - 404/639-6000
October 1995
Technical Version
Page 2
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