| Agent Name |
Iodine, radioactive |
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| Formula |
I |
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| Major Category |
Physical Agents |
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| Category |
Radionuclides |
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| Description |
Purplish black crystals; |
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| Sources/Uses |
The 14 major radioactive isotopes are produced by nuclear fission. Only iodine-129 has a long enough half-life (16 million years) to persist as an environmental contaminant. All the other isotopes have half-lives shorter than 60 days. I-129 is a high-level radioactive waste in spent nuclear fuel; it has no commercial uses. I-131 is used in nuclear medicine to diagnose and treat thyroid disorders. Other radioactive iodine isotopes are used for medical imaging (I-123), immunotherapy (I-124), and cancer treatment (I-125). [Argonne; EPA Radionuclides] |
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| Comments |
"There is sufficient evidence in humans that exposure during childhood to short-lived radioisotopes of iodine, including iodine-131, in fall-out from reactor accidents and nuclear weapons detonations causes thyroid cancer." [IARC]
Most Important Radionuclide: I-131
Source: Nuclear fission (3 atoms produced per 100 fissions)
Half-Life: 8 days
Effective Half-Life: 8 days
Specific Activity: 130,000 Ci/g
Decay Mode: Beta
GI Absorption: 100%
Lung Clearance Half-Time: <10 days for all compounds;
Critical Organ: Thyroid gland
Internal Toxicity: High
Annual Limit on Intake: 0.03 mCi
Tenth-Value Layer: 9.6 mm Pb
Gamma Ray Constant: 2.1 R/h @ 1 cm per mCi
Radiation Energy (MeV): Beta 0.606 (90%); Gamma 0.364 (82%); Gamma 0.637 (6.5%)
[See Glossary for references.] See "Radiation, ionizing."
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| Reference Link |
Iodine | Radiation Protection Program | US EPA |
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| Adverse Effects |
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| IARC Carcinogen |
Known Carcinogen |
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| Links to Other NLM Databases |
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| Health Studies |
Human Health Effects from Hazardous Substances Data Bank: IODINE, RADIOACTIVE IONIZING RADIATION
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