Thorium - Th

Thorium (Th)

Thorium is a silvery, weakly radioactive metal. It occurs naturally in minerals such as monazite and is more abundant in the Earth’s crust than uranium.

Uses and applications

Thorium oxide has a very high melting point and has been used in specialised high-temperature materials and as an industrial catalyst. Thorium has also been studied as a potential nuclear fuel material, but use depends on specialised fuel-cycle technologies.

Thorium and water management

Thorium and its decay products can occur in water due to natural deposits or activities that process mineral sands and other ores. Evaluation of drinking water or process water may need to consider both chemical form and radionuclide activity; appropriate monitoring depends on the source and applicable standards.

Occurrence and environmental context

Thorium is an actinide, and its occurrence and environmental behaviour depend on isotope, chemical form, and source. Natural geology, mineral processing, and nuclear-related activities can each affect whether an actinide is present in a water or waste stream. Monitoring should distinguish chemical concentration from radioactive activity where relevant.

Health and safety

Thorium requires careful handling because of its radioactive properties; for some elements, chemical toxicity is also relevant. Exposure depends on isotope, activity, chemical form, and route. Follow applicable radiation-protection procedures and substance-specific safety information.

Back to the periodic table of elements