Samarium Radioactivity.pdf

- Symbol: Sm
- Atomic Number: 62
- Atomic Weight: 150 (naturally occurring)
- Radioactive Properties:
- Sm-146: Half-life 100,000,000 years, Alpha decay, Specific Activity 0.000024 Ci/g
- Sm-151: Half-life 90 years, Beta decay, Specific Activity 27 Ci/g, Beta energy <0.001 MeV
- Occurrence: Three naturally occurring isotopes, with extremely long half-lives (trillions of years). Samarium-151 is the most concerning due to its 90-year half-life and beta decay.
- Sources: Found in minerals like monazite, bastnasite, cerite, gadolinite, and samarskite. Samarium-151 produced by nuclear fission in reactors.
- Uses: Catalyst, pyrophoric alloys, infrared absorbing glass, neutron absorber in nuclear reactors.
- Environmental Presence: Trace amounts in soil and water, higher concentrations at nuclear facilities. Less mobile in soil, not a major groundwater contaminant.
- Body Absorption: Primarily ingested, poorly absorbed (0.05%), deposited in liver (45%) and bone surface (45%), retained for almost 10 years.
- Health Effects: Samarium-151 increases cancer risk in liver and bone due to beta particles and gamma rays.
- Risk: Lifetime cancer mortality risk coefficients calculated for ingestion and inhalation. Similar risk for tap water as dietary ingestion.