Radon (Proposed)

The United States Environmental Protection Agency (EPA) sets drinking water standards and has determined that radon is of health concern at certain levels of exposure. Radon is a naturally occurring radioactive contaminant that occurs in ground water. It is a gas, and is released from water into the household air during water use. Radon has been found in epidemiology studies to cause lung cancer in humans at high exposure levels; at lower exposure levels the risk of lung cancer is reduced. EPA has set the drinking water standard for radon in public water supplies at 300 (Proposed Standard) picocuries per liter (pCi/l) to protect against lung cancer risk. Drinking water that meets the EPA standard is associated with little of this risk and is considered safe for radon.

Radium 226 (Proposed)

The United States Environmental Protection Agency (EPA) sets drinking water standards and has determined that radium 226 is of health concern at certain levels of exposure. Radium 226 is a naturally occurring radioactive contaminant that occurs primarily in ground water. Radium 226 has been found in epidemiology studies to cause bone cancer in humans at high exposure levels and is believed to cause other cancers as well; at lower exposure levels the risk of cancer is reduced. EPA has set the drinking water standard for radium 226 in public water supplies at 20 (Proposed Standard) picocuries per liter (pCi/l) to protect against cancer risk. Drinking water that meets the EPA standard is associated with little of this risk and is considered safe for radium 226.

Radium 228 (Proposed)

The United States Environmental Protection Agency (EPA) sets drinking water standards and has determined that radium 228 is of health concern at certain levels of exposure. Radium 228 is a naturally occurring radioactive contaminant that occurs primarily in ground water. Radium 228 has been found in epidemiology studies to cause bone cancer in humans at high exposure levels and is believed to cause other cancers as well; at lower exposure levels the risk of bone cancer is reduced. EPA has set the drinking water standard for radium 228 in public water supplies at 20 (Proposed Standard) picocuries per liter (pCi/l) to protect against cancer risk. Drinking water that meets the EPA standard is associated with little of this risk and is considered safe for radium.

Gross Alpha (Proposed)

The United States Environmental Protection Agency (EPA) sets drinking water standards and has determined that alpha emitting radionuclides may be of health concern at certain levels of exposure. Alpha emitters are primarily naturally occurring radioactive contaminants, but several derive from man-made sources. They may occur in either ground or surface water. Alpha emitters are believed to cause cancer in humans at high exposure levels because they emit ionizing radiation. At lower levels, the risk of cancer is reduced. EPA has set the drinking water standard for alpha emitters in public water supplies at 15 (Proposed Standard) picocuries per liter (pCi/l) to protect against cancer risk. Drinking water that meets the EPA standard is associated with little of this risk and is considered safe for alpha emitters.

Uranium (Proposed)

The United States Environmental Protection Agency (EPA) sets drinking water standards and has determined that uranium is of health concern at certain levels of exposure. Uranium is a naturally occurring radioactive contaminant that occurs both in ground and surface water. Uranium is believed to cause bone cancer and other cancers in humans at high exposure levels; at lower exposure levels the risk of bone cancer is reduced. EPA also believes uranium can be toxic to the kidneys. EPA has set the drinking water standard for uranium in public water supplies at 20 (Proposed Standard) micrograms per liter (μg/l) to protect against both cancer risk and the risk of kidney damage. Drinking water that meets the EPA standard is associated with little of this risk and is considered safe for uranium.

Beta and photon emitters (Proposed)

The United States Environmental Protection Agency (EPA) sets drinking water standards and has determined that beta and photon emitting radionuclides may be of health concern at certain levels of exposure. Beta and photon emitters are primarily man-made radioactive contaminants associated with the operation of nuclear power facilities, facilities using radioactive materials for research or manufacturing, or facilities where these materials are disposed. Some beta emitters are naturally occurring. Beta and photon emitters are expected to occur primarily in surface water. Beta and photon emitters are believed to cause cancer in humans at high exposure levels because they emit ionizing radiation. At lower levels, the risk of cancer is reduced. EPA has set the drinking water standard for beta and photon emitters in public water supplies at 4 (Proposed Standard) millirems effective dose equivalent per year (mrem ede/yr) to protect against cancer risk. Drinking water that meets the EPA standard is associated with little of this risk and is considered safe for beta and photon emitters.