Department of
Environmental Quality

The INL Oversight Program conducts monitoring of the following contaminants:

• Common ions and nutrients, measured in water samples, are naturally occurring elements and compounds that make up ninety-nine percent of all dissolved constituents in ground water or surface water. These include calcium, magnesium, sodium, potassium, chloride, fluoride, sulfate, nitrate, phosphorus, and dissolved carbon dioxide. These common ions and nutrients also make up the vast majority by weight of dissolved contaminants disposed of in waste water at INL. Together, these ions allow an assessment of the overall health of the groundwater.
• Trace metals, measured in water samples, are those metallic elements that are present at very low concentrations in groundwater. These elements also appear naturally, but at very low levels. Some of these, such as chromium, zinc, and barium were also disposed in INL wastewater.
• Gross alpha and beta radioactivity is monitored for in air and water. It can be natural or man-made. The test for these types of radioactivity is a screening test, measuring contaminants or naturally occurring radionuclides that emit alpha and beta radiation. If measured radioactivity exceeds expected background levels or historic INL operations suggest it, then further analyses are done to identify specific radioactive isotopes.
• Gamma-emitting radionuclides are monitored for in air, precipitation, water, soil, and milk by examining the spectrum of gamma radiation given off by a sample. This spectrum is like the spectrum of light we see when light passes through a prism. Cesium-137, Iodine-131, and naturally occurring Potassium-40 are a few isotopes specifically identified by their unique gamma-radiation energies. 
• Tritium is monitored for in precipitation, water vapor in the air, and water. Tritium is a radioactive isotope of hydrogen that is most often found taking the place of nonradioactive atoms in water molecules. It is made naturally in the atmosphere and it can be created in nuclear accelerators or reactors. It is present in spent nuclear fuel. Tritium gives off a low-energy beta particle and is not seen in a gross beta analysis. 
• Strontium-90, monitored for in selected water and air samples, is one of the many isotopes created when uranium or plutonium is fissioned in a reactor. It decays with beta radiation. 
• Technicium-99 is monitored for in selected water samples. This isotope is produced only in nuclear reactors and was historically released into the environment when wastewater was disposed of in ponds or wells. Technicium-99 decays with beta radioactivity. 
• Transuranic radionuclides have more protons in their nuclei than uranium. They are created in a nuclear reactor as a result of nuclear fission. Transuranic radionuclides are monitored for as particles captured on air filters. We also look for them dissolved in groundwater. Plutonium and americium are among the specific transuranic radionuclides we monitor. Transuranic elements typically emit alpha-particle radioactivity and may also be seen with screening for alpha radioactivity or by gamma-spectroscopy analysis. 
• Iodine-129 and chlorine-36 are monitored in ground water. They are radioisotopes that occur naturally at very low levels, but were also produced during worldwide nuclear weapons testing. These isotopes are also characteristic of INL wastewater, and travel quickly with ground water. These isotopes, which we test for only as part of special studies, are generally present at very low levels (to a million times lower than drinking water standards) and require special testing methods to see them at these atoms-per-liter levels.