Depleted uranium (DU) is a byproduct of the uranium enrichment process used in nuclear power plants and weapons production. DU has been used in medical and industrial applications for decades but since its use in recent military conflicts public concern been raised about potential health consequences from exposure to DU.

Radionuclides, which are radioactive isotopes, can be found in both food and drinking water due to natural processes and human activities. These substances may enter the food chain through root uptake from contaminated soil, atmospheric deposition onto crops, or transfer through water pathways.

Radon is a chemically inert, naturally occurring, radioactive gas. It has no smell, colour, or taste, and is produced from the natural radioactive decay of uranium which is found in rocks and soil.