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Record Information
Version 1.0
Creation Date 2009-03-06 18:58:06 UTC
Update Date 2013-04-25 08:32:53 UTC
Accession Number T3D0113
Identification
Common Name Thorium-228
Description Thorium is the chemical element of symbol Th and atomic number 90. It is a naturally occurring radioactive metal of the actinide series. In the environment, thorium exists in combination with other minerals, such as silica. Small amounts of thorium are present in all rocks, soil, water, plants, and animals. Twenty-seven radioactive isotopes of thorium, with mass number from 210 to 236, have been characterized. Naturally occurring thorium is composed mainly of one isotope: 232Th. The most abundant and/or stable isotopes are: 232Th (half-life of 14.05 billion years), 230Th (half-life of 75,380 years), 229Th (half-life of 7340 years), and 228Th (half-life of 1.92 years). Thorium is used to make ceramics, gas lantern mantles, and metals used in the aerospace industry and in nuclear reactions. Thorium can also be used as a fuel for generating nuclear energy. Thorium has been linked to increased risk of liver cancer. (S521, W511)
Compound Type
  • Inorganic Compound
  • Metal
  • Radioactive Isotope
  • Thorium Compound
Chemical Structure
Thumb
Synonyms
  1. Thorium, isotope of mass 228
  2. Thorium-228
Chemical Formula Th
Average Molecular Weight 228.028731348
Monoisotopic Molecular Weight 228.028731348
Chemical IUPAC Name
(²²⁸Th)thorium
CAS Registry Number 14274-82-9
SMILES
[228Th]
InChI Identifier
InChI=1S/Th/i1-4
InChI Key InChIKey=ZSLUVFAKFWKJRC-AHCXROLUSA-N
Chemical Taxonomy
Kingdom Inorganic Compounds
Super Class Homogeneous Metal Compounds
Class Homogeneous Actinide Compounds
Sub Class Not Available
Direct Parent Homogeneous Actinide Compounds
Alternative Parents Not Available
Molecular Framework Acyclic Compounds
Substituents Not Available
External Descriptors Not Available
DrugBank ID Not Available
PubChem Compound ID 61724 Link_out
KEGG ID Not Available
UniProt ID Not Available
OMIM ID Not Available
ChEBI ID Not Available
BioCyc ID Not Available
CTD ID Not Available
Stitch ID Thorium-228 Link_out
PDB ID Not Available
ACToR ID Not Available
Wikipedia Link http://en.wikipedia.org/wiki/Thorium-228 Link_out
Physical Properties
Appearance Not Available
Melting Point Not Available
Solubility Not Available
Predicted LogP 0
Toxicity Profile
Route of Exposure Oral (W511) ; Inhalation (W511) ; Dermal (W511)
Mechanism of Action The ionizing radiation produced by thorium causes cellular damage that includes DNA breakage, accurate or inaccurate repair, apoptosis, gene mutations, chromosomal change, and genetic instability. This leads to loss of normal cell and tissue homeostasis, and development of malignancy. Ionizing radiation that does not directly damage DNA can produce reactive oxygen intermediates that directly affect the stability of p53, an important enzyme in cell-cycle regulation, and produce oxidative damage to individual bases in DNA and point mutations by mispairing during DNA replication. (W510)
Metabolism Exposure to thorium can occur following inhalation, ingestion, or dermal exposure. Once in the body thorium accumulates mainly in the liver, spleen, lymph nodes, lungs, and bone. Transferrin plays a major role in the transport and cellular uptake of thorium. Thorium may combine with oxygen to form thorotrast (thorium dioxide), a colloid which may affect protein uptake. Thorium and thorotrast are excreted mainly in the faeces. (W511)
Toxicity Values Not Available
Lethal Dose Not Available
Carcinogenicity (IARC Classification) 1, carcinogenic to humans. (R264)
Uses/Sources Thorium can also be used as a fuel for generating nuclear energy. Thorium is used as an alloying element in magnesium, used in aircraft engines, imparting high strength and creep resistance at elevated temperatures. Thorium is also used as an alloying agent in gas tungsten arc welding (GTAW) to increase the melting temperature of tungsten electrodes and improve arc stability. Thorium is used to coat tungsten wire used in electronic equipment, improving the electron emission of heated cathodes. Thorium is used as a fertile material for producing nuclear fuel. Thorium is a very effective radiation shield, although it has not been used for this purpose as much as lead or depleted uranium. Uranium-thorium age dating has been used to date hominid fossils. (S521)
Minimum Risk Level Not Available
Health Effects Lungs and other internal organs can be penetrated by the alpha radiation produced by thorium. As a result, exposure to an aerosol of thorium can lead to increased risk of cancers of the lung, pancreas and blood. Exposure to thorium internally leads to increased risk of liver diseases. (S521)
Symptoms Exposure to high doses of ionizing radiation results in acute radiation syndrome, which can cause skin burns, hair loss, nausea, vomiting, dizziness, disorientation, low blood pressure, headache, fatigue, weakness, fever, birth defects, illness, infection, and death. (W510, W525)
Treatment Treatment reversing the effects of irradiation is currently not possible. Anaesthetics and antiemetics are administered to counter the symptoms of exposure, as well as antibiotics for countering secondary infections due to the resulting immune system deficiency. (W525)
References
General References
  • W511 — ATSDR - Agency for Toxic Substances and Disease Registry (1990). Toxicological profile for thorium. U.S. Public Health Service in collaboration with U.S. Environmental Protection Agency (EPA). [Link]
  • S521 — Wikipedia. Thorium. Last Updated 7 July 2009. [Link]
  • R264 — International Agency for Research on Cancer (2009). IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. [Link]
  • W510 — ATSDR - Agency for Toxic Substances and Disease Registry (1999). Toxicological profile for ionizing radiation. U.S. Public Health Service in collaboration with U.S. Environmental Protection Agency (EPA). [Link]
  • W525 — Wikipedia. Radiation poisoning. Last Updated 22 August 2009. [Link]

Targets

1. Cytokine receptor common subunit beta

High affinity receptor for interleukin-3, interleukin-5 and granulocyte-macrophage colony-stimulating factor.

The ionizing radiation produced by thorium causes cellular damage that includes DNA breakage, accurate or inaccurate repair, apoptosis, gene mutations, chromosomal change, and genetic instability. This leads to loss of normal cell and tissue homeostasis, and development of malignancy. (W510)
UniProt ID: P32927 Link_out
Gene: CSF2RB Link_out
Protein Sequence: FASTA
Gene Sequence: FASTA
SNPs: SNPJam Report Link_out
References:
  • W510 — ATSDR - Agency for Toxic Substances and Disease Registry (1999). Toxicological profile for ionizing radiation. U.S. Public Health Service in collaboration with U.S. Environmental Protection Agency (EPA). [Link]