Thorium (Th) is a radioactive element with 13 known isotopes. Th232 constitutes 99% of the naturally occurring Th, and is the isotope Dr. Hull tests for. Th decays by alpha-emission to produce radon, and over a period of time eventually converts to lead. This decay process produces alpha, beta, and gamma emissions.
Th is considered mildly toxic due to:
- the low level of radioactivity
- slight biochemical toxicity
Th health effects:
- may inhibit amylase and phosphatase enzymes
- binds to bone tissues
Th is as abundant in the Earth as lead, and is found when mining for titanium and rare Earth elements.
- incandescent gas lantern mantles
- refractory materials
- coating for tungsten in electronic applications
- tungsten-inert-gas welding electrodes