Thorium-232 is a primordial element that is distributed throughout the environment. It has a very long physical half-life (1.41 × 10 10 yr) and decays by emission of an alpha particle creating a series of radioactive daughters, many of which also emit alpha radiations. One of these daughters is an isotope of radon, 220Rn, viz., thoron.
The primary ways people are exposed to thorium are inhalation, intravenous injection, ingestion, and absorption through the skin. More than 2.5 million people worldwide were exposed to thorium in Thorotrast between 1930 and 1950. Once injected, Thorotrast remains in the body, resulting in lifelong exposure to thorium.
Thorotrast is a suspension containing particles of the radioactive compound thorium dioxide, ThO 2, that was used as a radiocontrast agent in medical radiography in the 1930s and 1940s. Use in some countries, such as the U.S., continued into the 1950s.. Thorium compounds produce excellent images because of thorium's high opacity to X-rays (it has a high cross section for …
Thorium metal usually does not constitute an external radiation exposure hazard since it emits mainly alpha-radiation at a low energy level. It may constitute an internal radiation hazard if it is absorbed into the body, thus delivering alpha emission onto tissues in which it is stored.
The risk of liver cancer is much higher among individuals who have long-term exposure to aflatoxins and also are chronically infected with hepatitis B or C. Industrial Chemicals. Exposure to chemicals such as vinyl chloride and thorium dioxide can increase the risk of a type of liver cancer called angiosarcoma (see Types of Liver Cancer).
White Paper Metals and Controls Corp. Thorium and Welding Exposure Model April 8, 2019 Page 3 of 9. This is a working document prepared by NIOSH's Division of Compensation Analysis and Support (DCAS) or its contractor for use in discussions
ANSI/AWS A5.12/AS.12M 98 (R2007) Specification for Tungsten and Tungsten Alloy Electrodes for Arc Welding and Cutting; IIS/IIW-VIII 1582-91 Estimated Radiation Doses From Thorium and Daughters Contained in Thoriated Welding Electrodes; IIS/IIW VIII 1702-93 Health Aspects in the Use of Thoriated Tungsten Electrodes.
Exposure to high levels of thallium can result in harmful health effects. A study on workers exposed on the job over several years reported nervous system effects, such as numbness of fingers and toes, from breathing thallium.
inhalation exposure to uranium. Chronic (long-term) inhalation exposure to uranium and radon in humans has been linked to respiratory effects, such as chronic lung disease, while radium exposure has resulted in acute leukopenia, anemia, necrosis of the jaw, and other effects. Cancer is the major effect of concern from the radionuclides.
Download Citation | Health effects following long-term exposure to thorium dusts: A twenty-year follow-up study in China | A twenty-year follow-up study was carried out at Baiyun Obo Rare-earth ...
Source Term. Uranium concentrations of 170 to 13,300 ppm (0.017 - 1.33 wt-%) were found in 15 types of porcelain powders of one manufacturer [Noël1988]. Uranium concentrations of 0.5 - 24.7 ppm were found in 8 types of porcelain powders marketed in Sweden [Sairenji1982]. Exposure of Workers Manufacturing Denture. Inhalation of powder dust
Cases of extreme exposure The danger from using these mantles around a campfire one or twice a year is not ... Problems with radioactivity arise in the long-term handling of the Thorium mantles ...
Radionuclide Basics: Thorium. ... However, people who live near thorium mining areas or near certain legacy industrial facilities may have increased exposure to thorium. Occasionally, items may be found with thorium in them, such as some older ceramic wares in which uranium and thorium were used in the glaze. These generally do not ...
potential exposure from thorium to members of the evaluated class during the period from January 1, 1987 through December 31, 1994. Therefore, NIOSH is reserving its evaluation of internal exposure from thorium for the period from January 1, 1987 through December 31, 1994 until activity-based thorium progeny data are available.
Aug 07, 2017· Radon is a naturally occurring radioactive gas. It's produced when uranium, thorium, and radium break down in soil, rock, and water. It's then released into the air. Radon is …
The authors evaluated radiation-related morbidity in a follow-up study involving 724 patients who received Thorotrast for cerebral angiography and 315 control patients who underwent similar diagnostic examinations with use of nonradioactive media.
Plutonium was discovered in 1940 in Berkeley, California. Since then, its production and use in nuclear power and nuclear weapons have exposed people around the world to radiation. This exposure is a source of possible adverse health effects. The following is an overview of plutonium and its health effects. This overview is an attempt to
Permissible Exposure Limits – Annotated Tables. OSHA recognizes that many of its permissible exposure limits (PELs) are outdated and inadequate for ensuring protection of worker health. Most of OSHA's PELs were issued shortly after adoption of the Occupational Safety and Health (OSH) Act in 1970, and have not been updated since that time.
Health Effects Following Long-term Exposure to Thorium Dusts. A Fourteen-year Follow-up study in China Chen Xing an, Cheng Young e, Zhen Rong Laboratory of Industrial Hygiene, Ministry of Public Health. P.O.Box 8018, Beijing, 100088, China INTRODUCTION A fourteen-year follow-up study was carried out at Baiyan Obo Rare-earth Iron Mine in China ...
Thorium Dioxide has not been tested for its ability to affect reproduction. Because Thorium Dioxide gives off very dangerous radiation, it has the potential for causing reproductive damage in humans. C-Other Long-Term Effects : Overexposure can occur with no acute symptoms. Low repeated exposures may scar the lungs.
Dec 10, 2013· The majority of adverse health outcomes related to uranium exposure have been observed in uranium mine, mill, and fabrication workers. Outcomes that may occur with uranium exposure based on both observed human effects and animal studies include non-malignant respiratory disease (fibrosis, emphysema) and nephrotoxicity.
Exposure to thorium internally leads to increased risk of liver diseases. (L1094) | 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.
Short-Term Exposure Can Be Deadly. First and foremost, short-term exposure to particle pollution can kill. Peaks or spikes in particle pollution can last from hours to days. Premature deaths from breathing these particles can occur on the very day that particle levels …
Exposure to an aerosol of thorium, such as contaminated dust, can lead to increased risk of cancers of the lung, pancreas, and blood, as lungs and other internal organs can be penetrated by alpha radiation. Internal exposure to thorium leads to increased risk of liver diseases.
This section highlights OSHA standards, directives (instructions to OSHA staff), and letters of interpretation (official interpretations of OSHA requirements) that pertain to occupational exposures to ionizing radiation. This section also provides an overview of the responsibilities of other federal ...
Thorium As Nuclear Fuel Thorium is a basic element of nature, like Iron and Uranium. Like Uranium, its properties allow it to be used to fuel a nuclear chain reaction that can run a power plant and make electricity (among other things).
Washington, DC: The National Academies Press. doi: 10.17226/4795. ... Exposure to arsenic, thorium, and copper may also cause portal hypertension without cirrhosis. ... Conference of Governmental Industrial Hygienists recommends an exposure limit of 5 ppm for an 8-hour day and a short-term exposure limit of 10 ppm. The National Institute for ...
* Thorium Nitrate can irritate the skin causing a rash or burning feeling on contact. * Exposure to Thorium Nitrate can irritate the eyes, nose, and throat. Chronic Health Effects The following chronic (long-term) health effects can occur at some time after exposure to Thorium Nitrate and can last for months or years: Cancer Hazard
Prolonged exposure to thorium radiation has been linked to. Read More. Safety Aspects in Thorium Mining and Milling - Thorium Energy World. monazite and its chemical processing to obtain thorium values. The process . Therefore external exposure will depend on the varying concentration of monazite.
EPA Facts about Thorium What is thorium? Thorium is a naturally occurring radioactive metal that is found at low levels in soil, rocks, water, plants, and animals. Almost all naturally occurring thorium exists in the form of either radioactive isotope thorium-232, thorium-230, and thorium-228. There are more than 10 other