United States
Environmental Protection
Agency i
Office of Water
4601
EPA811-F-95-002d-T
October 1995
National Primary Drinking
Water Regulations
Chromium
CHEMICAL/ PHYSICAL PROPERTIES
CAS NUMBER: 7440-47-3
COLOR/ FORM/ODOR: Chromium is metal .found in nature only in
the combined state.
SOIL SORPTION COEFFICIENT: N/A; Low mobility
BIOCONCENTRATION FACTOR: BCF in plants, 1000; in snails,
1,000,000; expected to accumulate in aquatic organisms.
COMMON ORES: oxide- Iron chromite
SOLUBILITIES: .
chloride- soluble in cold water
chromate- 0.2 mg/L (lead salt)
chromate- 873 g/L at 30 deg C (sodium salt)
chromate oxide-insoluble
dichromate- 2380 g/L at 0 deg C (sodium salt)
dioxide- insoluble
oxide- insoluble
sulfate- insoluble
trioxide- 617 g/L at 0 deg C
DRINKING WATER STANDARDS
MCLG: 0.1 mg/l
Met: 0.1 mg/l
HAt(child): 1-to 10-day: 1 mg/L
Longer-term: 0.2 mg/L
Note: These standards are based on the total concen-
tration of the trivalent and hexayalent forms of dissolved
chromium (Cr3* and Cr6+).
preservatives, organic chemical synthesis, photochemi-
cal processing and industrial water treatment. In medi-
cine, chromium compounds are used in astringents and
antiseptics. They also are used in cooling waters, and in
the leather tanning industry, in catalytic manufacture,
and in fungicides; as an algaecide against slime forming
bacteria and yeasts in brewery processing water and
brewery warmer water.
Chromic acid consumption patterns in 1988: wood
preserving, 63%; metal finishing, 22%; other, including
, . . '
Acute: EPA has found chromium to potentially cause
the following health effects from acute exposures at
levels above the MCL: skin irritation or ulceration.
Drinking water levels which are considered "safe" for
short-term exposures: Fora 10-kg (22 Ib.) child consum-
ing 1 liter of water per day, a one- to ten-day exposure to
1 mg/L; a longer-term (7 years) exposure to 0.2 mg/L
Chronic: Chromium has the potential to cause the
following health effects from long-term exposures at
levels above the MCL: damage to liver, kidney circula-
tory and nerve tissues; dermatitis.
* •
Cancer; There is no evidence that chromium in drink-
ing water has the potential to cause cancer from lifetime
exposures in drinking water.
USAGE PATTERNS
Chromium and its compounds are used in metal alloys
such as stainless steel; protective coatings on metal;
magnetic tapes; and pigments for paints,.cement, paper,
rubber, composition floor covering and other materials.
Other uses include: chemical intermediate for wood
Toxic RELEASE INVENTORY -
RELEASES TO WATER AND LAND: 1987 TO 1993
,.-.' Water
TOTALS (in pounds) 2.876,055
• . " t •
TX 102.079
NC 43,522
IN 85,570
OH 51,830
UT 1,750
AR 2,300
KY ' ' • 255
PA 110,149
GA 679,721
ID 91,750
.
Major Industries*
Indust organics 3,272
Steelworks, Blast fum. 609,174
Electrometallurgy 33,269
Copper smelting, refining 1 ,750
Nonferrous smelting . 2,300
Inorganic pigments 88,721
Pulp mills 985.800
Land
196,880,624
64,301,920
55,217,044
15,955,895
8,319,600
5,817,015
3,532.000
.: 2,491,519
2,337,905
1,404,698
1,404.870
•
120.707.814
16,638,880
10,796,928
5.817.015
3.532.000
1.375,700
224,198
* State/Industry totals only include facilities with releases
greater than a certain amount - usually 1000 to 10,000 Ibs.
October1995
Technical Version
Printed on Recycled Paper
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water treatment, magnetic particles and catalysts, 7%;
exports, 8%. Demand: 1987:57,500 tons; 1988:62,500
tons; 1992 (projected): 78,800 tons.
Sodium Bichromate consumption patterns in 1988:
chromic acid, 54%; leather tannirg, 9%; chromium oxide,
9%; pigments, 8%; wood preservation, 5%; other, includ-
ing drilling muds, catalysts, water treatment, metal finish-
ing, 5%; exports, 10%. Demand: 1987: 150,000 tons;
1988:164,000 tons; 1992 (projected): 180,000 tons
RELEASE PATTERNS
Chromium occurs in nature mostly as chrome iron ore,
or chromite. Though widely distributed in soils and plants,
it is rare in natural waters. The two largest sources of
chromium emission in the atmosphere are from the
chemical manufacturing industry and combustion of natu-
ral gas, oil, and coal.
Other sources include wind transport from road dust,
cement producing plants because cement contains chro-
mium, the wearing down of asbestos brake linings from
automobiles or similar sources of wind carried asbestos
since asbestos contains chromium, incineration of mu-
nicipal refuse and sewage sludge, exhaust emission
from automotive catalytic converters, emissions from
cooling towers that use chromium compounds as rust
inhibitors, waste waters from electroplating, leather tan-
ning, and textile industries when discharged into surface
waters, and solid wastes from chemical manufacture.
From 1987 to 1993, according to the Toxics Release
Inventory, chromium compound releases to land and
water totalled nearly 200 million pounds, of which about
99 percent was to land. These releases were primarily
from industrial organic chemical industries which use
chromium as an intermediate. The largest releases oc-
curred in Texas and North Carolina, The largest direct
releases to water occurred in Georgia and Pennsylvania.
Background levels in water average 1 ug/L while
municipal drinking water contain 0.1-35 ug/L. The higher
values of chromium can be related to sources of anthro-
pogenic pollution. In ocean water, the mean chromium
concentration is lower than in river water, and its value is
0.3 ug/l, with a range of 0.2 to 50 ug/l.
A survey of 3834 tap waters reported the concentra-
tions of chromium to range from 0.4 to 8.0 ug/l. The
reported chromium concentrations in this study may be a
little higher than the actual values due to inadequate
flushing of tap water before collection of samples. This
indicates that the concentration of chromium in house-
hold tap water may increase due to plumbing materials.
ENVIRONMENTAL FATE
Chromium is not likely to migrate to ground water. A
field trial on the application of wastewater treatment
sludge to soils found movement of heavy metals, includ-
ing chromium, from the soil surface to a depth of 10 cm,
but most of the metal (mean 87%) remained in the upper
5 cm of soil. Uptake by plants is generally low; it was
found to be greater from ultrabasic soils by a factor of 5-
40 than on calcareous or silica-based soils.
Chromium compounds are very persistent in water.
Most of the chromium in surface waters may be present
in particulate form as sediment. Some of the particulate
chromium would remain as suspended matter and ulti-
mately be deposited in sediments.
The exact chemical forms of chromium in surface
waters are not well defined. Although most of the soluble
chromium in surface waters may be present as Cr(VI), a
small amount may be present as Cr(lll) organic com-
plexes. Hexavalent chromium is the major stable form of
chromium in seawater; however, Cr(VI) may be reduced
to Cr(lll) by organic matter present in water, and may
eventually deposit in sediments.
Though little data is available, there is a high potential
for bioconcentration of chromium in aquatic organisms.
Snails showed an accumulation factor of 1x10^.
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 > 0.1 mg/L, sample quarterly.
ANALYSIS:
REFERENCE SOURCE
EPA 600/4-79-020
NTISPB 91-231498
Standard Methods
METHOD NUMBERS
218.2
3113B;3120
200.7
TREATMENT
BEST AVAILABLE TECHNOLOGIES
Coagulation/Filtration; Ion Exchange, Reverse Osmosis, Lime Softening
(for Crlll only)
FOR ADDITIONAL INFORMATION:
4 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
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