RADIUM IN DRINKING WATER
WHAT IS RADIUM?
Radium (Ra) is a naturally occurring
radioactive element that is present in varying amounts in rocks and soil within
the earth's crust. Small quantities of radium derived from these sources can
also be found in groundwater supplies. Radium can be present in several forms
(isotopes). The most common isotopes in Illinois groundwater are Ra-226 and
Ra-228. The primary form of radiation emitted by radium is the alpha
IS RADIUM IN MY WATER?
Surface water is usually low in radium but
groundwater can contain significant amounts of radium due to local geology.
Deep bedrock aquifers used for drinking water sometimes contain levels of
Ra-226 and Ra-228 that exceed regulatory standards. In Illinois, high radium
levels occur primarily in the northern third of the state due to the presence
of radium in the granite bedrock that surround aquifers from which water
supplies are drawn. All public water supply wells are tested regularly for
Most of the private wells in Illinois draw
their water from aquifers that are much shallower than those used by public
water supplies. Most shallow aquifers do not contain significant amounts of
radium. However, radium has been found in some private and non-community public
wells. Radium cannot be seen, tasted, or smelled in your drinking water. Unless
your water supply has been tested for radium, you should not assume your water
The testing process for radium in water begins
with a screening for total alpha particle activity. If total alpha activity is
elevated, further testing for radium is conducted. Radium samples from public
water supplies are taken quarterly, tested by the Illinois Department of
Nuclear Safety, and averaged over a one- year period.
IS RADIUM IN WATER HARMFUL TO MY
Radium in water may pose a hazard to human
health when the water is used for drinking. No more than 20% of the ingested
radium is absorbed from the digestive tract and distributed throughout the
body. The rest is excreted unchanged from the gut. Some absorbed radium is
excreted in urine. The remaining radium behaves similarly to calcium and is
deposited in the tissues of the body, especially bone. The radiation received
externally through showering, washing, or other uses of radium-containing water
is insignificant since the skin blocks the alpha radiation.
Internally deposited radium emits radiation as
alpha particles that may then damage tissues found within the surrounding few
millimeters. Radium is not known to cause adverse health effects at levels
generally encountered in drinking water, diet, or the environment. However,
studies of workers exposed to high levels of radium and other sources of alpha
radiation for extended periods show that high levels of radium may cause
depression of the immune system, anemia, cataracts, fractured teeth, and some
types of cancer.
IS THERE A SAFE LEVEL OF RADIUM IN DRINKING
Based upon our current knowledge, it is assumed
that any radiation exposure from any source carries some degree of risk.
However, the U.S. Environmental Protection Agency (USEPA) has established a
maximum contaminant level (MCL) for radium in public water supplies of 5
picoCuries per liter (pCi/l). The MCL for radium has been set well below levels
for which health effects have been observed and is therefore assumed to be
protective of public health. Public water supplies whose radium levels exceed 5
pCi/l are not inherently "unsafe" but are required to notify the
public that the water exceeded the MCL. They must also evaluate ways to reduce
the radium levels in the system's water. Water containing elevated levels of
radium may carry a correspondingly higher level of risk to health.
WHAT HAPPENS IF A PUBLIC WATER SUPPLY
EXCEEDS THE STANDARD?
The levels of radium in the public water
supplies of some Illinois communities slightly exceed the current MCL. A public
water supply exceeding the standard is not permitted to extend water mains and
is placed on a "restricted status" list. However, some communities
have applied for and been granted a temporary variance from these regulations
by the Illinois Pollution Control Board (IPCB) which adopts environmental
CAN RADIUM BE REMOVED FROM WATER?
A number of methods are available to public
water supplies to remove radium from water. Ion exchange, lime softening, and
reverse osmosis are the most common and can remove up to 90% of radium present.
Ion exchange (i.e., water softeners) and reverse osmosis units are also
available for home installation and can often remove 90% of the radium present
along with hardness removal. For some people, an undesired effect of ion
exchange is the addition of sodium to the treated water. Those on low sodium
(salt) diets should consider this before installing a softener.
WHERE CAN I GET MORE INFORMATION?
Illinois Department of Public Health
Division of Environmental Health
525 W. Jefferson St.
Springfield, IL 62761
TTY (hearing impaired use only) 800-547-0466
This fact sheet was supported in part by
funds from the Comprehensive Environmental Response, Compensation, and
Liability Act trust fund through a cooperative agreement with the Agency for
Toxic Substances and Disease Registry, Public Health Service, U.S. Department
of Health and Human Services.