CHROMIUM
FACT SHEET ON A DRINKING WATER CHEMICAL CONTAMINANT
GENERAL INFORMATION
Synonyms
None
Chemical Description:
A relatively rare, naturally occurring element
(occurs as various salts) in the earth's crust
Properties:
A metal which exists in tnvalent and
hexavalent valence (oxidation) stats??, thQ
tnvalent being the more i>rp-v(:l»r-1 state
Exists principally us fn- and hexavalent
chromium salts, both of which are stable in
water and exist in dynamic equilibrium with
each other
Water solubility of chromium salts is compound
specific
« Tnvalent chromium (Crlll) is oxidized to
hexavalent chromium (CrVI) in the presence of
chlorine at concentrations similar to those used
to disinfect drinking water
Production and Use:
Chromium and its salts (chromite is the most
widely used ore) have a variety of uses
chrome alloys, metal refmishing. and
corrosion resistance
in the leather tanning industry
in the textile industry
in pigments and paints
in fungicides and wood preservatives
ENVIRONMENTAL PROFILE
Occurrence:
Estimated that occurrence above the MCI in
drinking water is negligible
Naturally occurs in soil and, as a
consequence, in food
Data indicates that detection of chromium in
surface and ground water supplies are usually
the result of naturally-occurring chromium
leaching from mineral deposits
Exists mainly in the tnvalent or hexavalent
states in natural bodies of water
Releases:
Contamination of water by chromium is
generally a result of runoff from old mining
operations and improper waste disposal from
plating operations
Environmental Fate:
Released to air will adsorb to particulars
matter in air; not expected to exist in gaseous
form, likely to be relatively unreactive.
removed from air by wet and dry deposition
Released to toll: limited soil mobility (will
ocii-uri:' fo soil particles) and is likely to remain
ii. tlifc upper 5 cm. of soil, uptake of chromium
in plante is generally low. not likely to migrate
to ground water
Released to surface waters: highly persistent in
water, will adsorb to suspended paniculate
matter and ultimately be deposited in
sediments
High potential for bioaccumulation, especially
in fish and other aquatic organisms
HEALTH EFFECTS
Humans:
Crlll is an essential nutrient for the metabolism
of carbohydrates when consumed within the
Recommended Daily Intake range of 0 05-0 2
mg/day
Only CrVI crosses cell membranes, it is reduced
to Crlll intracellularly
CrVI compounds are generally more toxic than
Crlll compounds:
Chronic inhalation of dust or air containing
CrVI may cause respiratory problems
Chronic and subchronic dermal exposure to
solutions containing high levels of CrVI may
cause skin irritation and/or ulceration of the
skin
Experimental Animals:
Low oral toxicity because it is not well
absorbed in the gastrointestinal tract
Both short-term, and long-term drinking
water studies with high levels of both Crlll
and CrVI showed no adverse health effects
High mutagenic potential
Equivocal evidence on whether mgestion of
drinking water contaminated by chromium
causes cancer
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REGULATORY PROFILE
Existing Standards:
Ciean Air Act (CAA): Not regulated
Ciean Water Act (CWA):
Criteria established
Resource Conservation arid Recovery Act
(RCRA):
Not regulated
Superfund (CERCLA):
Hazardous waste
SARA: Toxic chemical
Federal Insecticide, Fungicide, and
Rodenticide Act (FIFRA):
Registered (Chromium compounds)
Toxic Substances Control Act (TSCA):
Not regulated
HEALTH INFORMATION
Maximum Contaminant Level Goals (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 0 1 mg/L to protect against adverse
health effects
MCLG for Chromium = 0.1 mg/L
(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 MCL = 0.05 mg/I
MCL for Chromium = 0.1 mg/L
(effective July 1992)
EPA Health Advisories (HA):
Shoit-term HAs: Provide acceptable
concentrations of contaminants in water for
up to 10 day exposures, primarily to evaluate
the public health nsk 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 on
MCLG
Health aviscries
Short-term HA for a child = 1 mgi I
Longer-term HA for a child = 0.2 mg/I
Longer-term HA for an adult = 0.8 mg I
Lifetime HA 0.1 mg/I
ANALYTICAL METHODS
Graohite Furnace Atomic Absorbtion
EPA Method 2182
Inductively Coupled Plasma
EPA Method 200 7
WATER TREATMENT
Permanent Treatment
lest Available Technology (SAl):
Coagulation/Filtration
Lime Softening
Reverse Osmosis
Ion Exchange
SHORT-TERM HAZARD ELIMINATION
If the drinking water standards ore exceeded.
install BAT or use on alternative drinking water
supply such as bottled water
ADDITIONAL HELP
State or county health officials can indicate a
certified laboratory for testing
Experts in the state Department of
Environmental Protection or Natural Resources
may also be of help
The EPA has toll-free numbers for further
information on drinking water Quality.
treatment technologies, for obtaining Health
Advisories, and for other regulatory information
EPA Hotlines are available Monday through
Friday
Safe Drinking Water
National Pesticides:
Sup.ifund/ RCRA:
For information on the Clean
(202) 260-7301
For information on the Toxic Substances
Control Act, call (202) 554-1404
For information on the Clean Air Act, call
(919) 541-2777
800.426.4791
800-858-7378
800.424-9346
Water Act, call
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