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 particle.

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 radium.

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 is radium-free.

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 HEALTH?

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 WATER?

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 regulations.

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
217-782-5830
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.