Combined uranium is a radioactive element found in rocks and soil. It can enter water through mining and processing, potentially causing kidney damage and increasing cancer risk.

Uranium occurs naturally in the Earth's crust, but human activities like mining and nuclear fuel production can increase its concentration in water sources. Measured in picocuries per liter (pCi/L), combined uranium includes all isotopes of this element. While ingestion primarily affects the kidneys, long-term exposure may elevate cancer risk. Water treatment methods such as reverse osmosis and ion exchange can effectively remove uranium from drinking water. Regular testing is crucial, especially in areas with known uranium deposits or nuclear facilities nearby.