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Other radionuclides are produced from human activities, such as nuclear weapons testing, nuclear facility releases, and radioactive waste. The presence of tritium (H-3), for example, was produced by nuclear detonations in the 1950s and 60s, and its presence in groundwater indicates that the groundwater is relatively young (< 60 or so years old). Similarly, cesium-137, also produced by nuclear tests, mostly adheres to sediments—its peak activity in a sediment core indicates the depth of sediment that corresponds to the early 1960s, when levels of cesium-137 in the atmosphere reached their peak.
RELATED USGS RESEARCH
Metals and Other Trace Elements
Evaluation of Radon in Groundwater and Indoor Air in Pennsylvania
The Geology of Radon
ADDITIONAL RESOURCES
U.S. Environmental Protection Agency
Radionuclides in Ecosystems
Radionuclides in Drinking Water
Safe Drinking Water Act: Radionuclides in drinking water
Commonly Encountered Radionuclides
Agency for Toxic Substances and Disease Registry (ATSDR)
Radionuclides (radioactive materials)
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