A baseline of natural radionuclides in water and sediment of a pristine coastal ecosystem: The Xcalak and Mahahual coral reef lagoons in the western Caribbean.

In ecosystems, natural radionuclides are present in the environment and living organisms. The U natural decay chain produces multiple radioactive elements, such as U, Ra, Pb, and Po. These radionuclides can be found in air, water, rocks, soil, and other biotic and abiotic components, mainly derived from minerals, such as zircon and apatite.