化合物详情

CAS7440-29-1

分子式Th

分子量232.03806 g/mol

非危品

Hazards Summary | Thorium is a naturally occurring, radioactive substance. 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. Soil contains an average of about 6 parts of thorium per million parts of soil (6 ppm). More than 99% of natural thorium exists in the form of thorium-232. It breaks down into two parts-a small part called "alpha" radiation and a large part called the decay product. The decay product is also not stable and continues to break down through a series of decay products until a stable product is formed. During these decay processes, radioactive substances are produced. These include radium and radon. These substances give off radiation, including alp...

科学粮草官-词典编辑部，修订于：2026-07-06

Toxicity

Body Burden

273 men exposed to thorium and other rare earths between 1940 and 1973 at a monazite sand refinery were studied at Argonne National Laboratory from 1976 to 1980. In vivo measurements of body burden were made by counting gamma rays emitted by daughter products of retained thorium and by measuring exhaled thoron. Health status was ascertained through questionnaire, physical exam, and clinical lab tests. Measured body burden was found to be higher in those with a history of longer exposure. All parameters of the complete blood count were examined for evidence of an effect due to thorium. Comparisons of high and low body burden groups showed that only age and cigarette smoking had an effect on complete blood count parameters.

Probable Routes of Human Exposure

PRINCIPAL HAZARDS FROM THORIUM IN INDUSTRY ARE INHALATION OF THORIUM DUST & OF THORON GAS & ITS DECAY PRODUCTS, & EXPOSURE TO EXTERNAL BETA & GAMMA RADIATION. INHALATION HAZARD IS GREATEST IN DUSTY OPERATIONS SUCH AS GRINDING OF METALS, CERAMICS, HANDLING OF THORIUM POWDER, & CONTAMINATION FROM THORIUM FIRES.

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. (L1837, L1852)

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. (L1852)

Target Organs

Cancer, Respiratory (From the Nose to the Lungs)

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. (L1094)

Exposure Routes

Inhalation (L1094)

Toxicity Summary

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. (L1837) CDC-ATSDR Toxicological Profile

Carcinogen Classification

1, carcinogenic to humans. (L135)

Evidence for Carcinogenicity

Internalized radionuclides that emit alpha-particles are carcinogenic to humans (Group 1). In making this overall evaluation, the Working Group took into consideration the following: Alpha-particles emitted by radionuclides, irrespective of their source, produce the same pattern of secondary ionizations and the same pattern of localized damage to biological molecules, including DNA. These effects, observed in vitro, include DNA doublestrand breaks, chromosomal aberrations, gene mutations and cell transformation. All radionuclides that emit alpha-particles and that have been adequately studied, including radon-222 and its decay products, have been shown to cause cancer in humans and in experimental animals. Alpha-particles emitted by radionuclides, irrespective of their source, have been...

Antidote and Emergency Treatment

Decontamination. 1. Exposure to particle-emitting solids or liquids. The victim is potentially highly contaminating to rescuers, transport vehicles, and attending health personnel. 1. Remove victims from exposure, and if their conditions permit, remove all contaminated clothing and wash the victims with soap and water. b. All clothing and cleansing water must be saved, evaluated for radioactivity, and properly disposed of. c. Rescuers should wear protective clothing and respiratory gear to avoid contamination. At the hospital, measures must be taken to prevent contamination of facilities and personnel. d. Induce vomiting or perform gastric lavage if radioactive material has been ingested. Administer activated charcoal, although its effectiveness is unknown. Certain other adsorbent mater...