This is a fact sheet 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 is Chromium?
Chromium is a metal found in natural deposits as ores containing other
elements. It exists in three forms (divalent, trivalent, and
hexavalent) and is carcinogenic only in the hexavalent form. By
comparison, chromium III (trivalent chromium) is actually necessary to
the body to metabolize sugar. It is important to remember this
How is Chromium used?
The greatest use of chromium is 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. Its soluble forms are used in wood preservatives.
Why is Chromium 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
The MCLG for chromium has been set at 0.1 parts per million (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 has also been set at 0.1 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: EPA has found chromium to potentially cause the following
health effects when people are exposed to it at levels above the MCL for
relatively short periods of time: skin irritation or ulceration.
Long-term: Chromium has the potential to cause the following
effects from a lifetime exposure at levels above the MCL: damage to
liver, kidney circulatory and nerve tissues; skin irritation.
The NIH released a study in May 2007 that indicated that hexavalent
chromium can cause cancer when ingested through drinking water. This had
been suspected but no studies had been able to offer significant proof
of the theory; researchers did find, however, that lab animals developed
tumors in their mouths after exposure to hexavalent chromium through
their drinking water.
How much Chromium is produced and released to the environment?
Production of the most water soluble forms of chromium, the chromate and
dichromates, was in the range of 250,000 tons in 1992. Though chromium
occurs in nature mostly as chrome iron ore and is widely found 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 natural gas, oil, and coal.
From 1987 to 1993, according to the Toxics Release Inventory,
chromium compound releases to land and water totaled nearly 200 million
pounds. These releases were primarily from industrial organic chemical
industries. The largest releases occurred in Texas and North Carolina.
The largest direct releases to water occurred in Georgia and
What happens to Chromium when it is released to the environment?
When released to land, chromium compounds bind to soil are not likely to
migrate to ground water. They are very persistent in water as sediments.
There is a high potential for accumulation of chromium in aquatic life.
How will Chromium be detected in and removed from my drinking
The regulation for chromium became effective in 1992. Between 1993 and
1995, EPA required your water supplier to collect water samples once and
analyze them to find out if chromium is present above 0.1 ppm. 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 the MCL,
your water supplier must take steps to reduce the amount of chromium so
that it is consistently below that level. The following treatment
methods have been approved by EPA for removing chromium:
Coagulation/Filtration, Ion Exchange, Reverse Osmosis, Lime Softening.
How will I know if Chromium is in my drinking water?
If the levels of chromium exceed the MCL, 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.
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).
Drinking Water Standards:
|Mclg: 0.1 ppm (parts per million)
Mcl: 0.1 ppm
Chromium Releases to Water and Land, 1987 to 1993 (in pounds):
|Top Ten States*|
|Steelworks, Blast furn.
|Copper smelting, refining
* Water/Land totals only include facilities with releases greater
than a certain amount - usually 1000 to 10,000 lbs.
Note: This fact sheet is part of a larger publication
adapted from U.S. EPA publication: EPA National Primary Drinking Water