Naturally occurring radioactive materials (NORM) and technologically enhanced naturally occurring radioactive materials (TENORM) consist of materials, usually
industrial waste
Industrial waste is the waste produced by industrial activity which includes any material that is rendered useless during a manufacturing process such as that of factories, mills, and mining operations. Types of industrial waste include dirt and ...
s or by-products enriched with
radioactive elements found in the environment, such as
uranium,
thorium and
potassium and any of their decay products, such as
radium and
radon.
Produced water discharges and spills are a good example of entering NORMs into the surrounding environment.
Natural
radioactive elements are present in very low concentrations in Earth's crust, and are brought to the surface through human activities such as
oil and gas exploration or
mining, and through natural processes like leakage of
radon gas to the atmosphere or through dissolution in ground water. Another example of TENORM is
coal ash produced from coal burning in
power plants. If radioactivity is much higher than background level, handling TENORM may cause problems in many industries and transportation.
NORM in oil and gas exploration
Oil and gas TENORM and/or NORM is created in the production process, when produced fluids from reservoirs carry sulfates up to the surface of the Earth's crust. Some states, such as
North Dakota, uses the term "diffuse NORM". Barium, calcium and strontium sulfates are larger compounds, and the smaller atoms, such as
radium-226 and
radium-228, can fit into the empty spaces of the compound and be carried through the produced fluids. As the fluids approach the surface, changes in the temperature and pressure cause the barium, calcium, strontium and radium sulfates to precipitate out of solution and form scale on the inside, or on occasion, the outside of the tubulars and/or casing. The use of tubulars in the production process that are NORM contaminated does not cause a health hazard if the scale is inside the tubulars and the tubulars remain downhole. Enhanced concentrations of the radium 226 and 228 and the daughter products such as
lead-210 may also occur in sludge that accumulates in oilfield pits, tanks and lagoons. Radon gas in the natural gas streams concentrate as NORM in gas processing activities. Radon decays to lead-210, then to
bismuth-210
Bismuth (83Bi) has 41 known isotopes, ranging from 184Bi to 224Bi. Bismuth has no stable isotope, stable isotopes, but does have one very long-lived isotope; thus, the standard atomic weight can be given as . Although bismuth-209 is now known to b ...
,
polonium-210
Polonium-210 (210Po, Po-210, historically radium F) is an isotope of polonium. It undergoes alpha decay to stable 206Pb with a half-life of 138.376 days (about months), the longest half-life of all naturally occurring polonium isotopes. First i ...
and stabilizes with
lead-206. Radon decay elements occur as a shiny film on the inner surface of inlet lines, treating units, pumps and valves associated with propylene, ethane and propane processing systems.
NORM characteristics vary depending on the nature of the waste. NORM may be created in a crystalline form, which is brittle and thin, and can cause flaking to occur in tubulars. NORM formed in carbonate matrix can have a density of 3.5 grams/cubic centimeters and must be noted when packing for transportation. NORM scales may be white or a brown solid, or thick sludge to solid, dry flaky substances. NORM may also be found in oil and gas production produced waters.
Cutting and reaming oilfield pipe, removing solids from tanks and pits, and refurbishing gas processing equipment may expose employees to particles containing increased levels of alpha emitting radionuclides that could pose health risks if inhaled or ingested.
NORM is found in many industries including
* The coal industry (mining and combustion)
* Metal mining and smelting
* Mineral sands (rare earth minerals, titanium and zirconium).
* Fertilizer (phosphate) industry
* Building industry
Hazards
The hazards associated with NORM are inhalation and ingestion routes of entry as well as external exposure where there has been a significant accumulation of scales.
Respirators may be necessary in dry processes, where NORM scales and dust become air borne and have a significant chance to enter the body.
The hazardous elements found in NORM are radium 226, 228 and radon 222 and also daughter products from these radionuclides. The elements are referred to as "
bone seekers
A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, and e ...
" which when inside the body migrate to the bone tissue and concentrate. This exposure can cause bone cancers and other bone abnormalities. The concentration of radium and other daughter products build over time, with several years of excessive exposures. Therefore, from a liability standpoint an employee that has not had respiratory protection over several years could develop bone or other cancers from NORM exposure and decide to seek compensation such as medical expenses and lost wages from the oil company which generated the TENORM and the employer.
Radium radionuclides emit alpha and beta particles as well as gamma rays. The radiation emitted from a radium 226 atom is 96% alpha particles and 4% gamma rays. The
alpha particle is not the most dangerous particle associated with NORM, as an external hazard. Alpha particles are identical with helium-4 nuclei. Alpha particles travel short distances in air, of only 2–3 cm, and cannot penetrate through a dead layer of skin on the human body. However, some radium alpha particle emitters are "bone seekers" due to radium possessing a high affinity for chloride ions. In the case that radium atoms are not expelled from the body, they concentrate in areas where chloride ions are prevalent, such as bone tissue. The
half-life for radium 226 is approximately 1,620 years, and will remain in the body for the lifetime of the human — a significant length of time to cause damage.
Beta particle
A beta particle, also called beta ray or beta radiation (symbol β), is a high-energy, high-speed electron or positron emitted by the radioactive decay of an atomic nucleus during the process of beta decay. There are two forms of beta decay, β∠...
s are high energy electrons or positrons. They are in the middle of the scale in terms of ionizing potential and penetrating power, being stopped by a few millimeters of plastic. This radiation is a small portion of the total emitted during radium 226 decay. Radium 228 emits beta particles, and is also a concern for human health through inhalation and ingestion. Beta particles are
electrons or
positron
The positron or antielectron is the antiparticle or the antimatter counterpart of the electron. It has an electric charge of +1 '' e'', a spin of 1/2 (the same as the electron), and the same mass as an electron. When a positron collides ...
s and can travel farther than alpha particles in air.
The
gamma rays emitted from radium 226, accounting for 4% of the radiation, are harmful to humans with sufficient exposure. Gamma rays are highly penetrating and some can pass through metals, so
Geiger counter
A Geiger counter (also known as a Geiger–Müller counter) is an electronic instrument used for detecting and measuring ionizing radiation. It is widely used in applications such as radiation dosimetry, radiological protection, experimental ph ...
s or a
scintillation probe are used to measure gamma ray exposures when monitoring for NORM.
Alpha and beta particles are harmful once inside the body. Breathing NORM contaminates from dusts should be prevented by wearing respirators with particulate filters. In the case of properly trained occupational NORM workers, air monitoring and analysis may be necessary. These measurements, ALI and DAC, are calculated values based on the dose an average employee working 2,000 hours a year may be exposed to. The current legal limit exposure in the United States is 1 ALI, or 5 rems. A rem, or
roentgen equivalent man
The roentgen equivalent man (rem) is a CGS unit of equivalent dose, effective dose, and committed dose, which are dose measures used to estimate potential health effects of low levels of ionizing radiation on the human body.
Quantities measure ...
, is a measurement of absorption of radiation on parts of the body over an extended period of time. A DAC is a concentration of alpha and beta particles that an average working employee is exposed to for 2,000 hours of light work. If an employee is exposed to over 10% of an ALI, 500 mREM, then the employee's dose must be documented under instructions with federal and state regulations.
Regulation
United States
NORM is not federally regulated in the United States. The
Nuclear Regulatory Commission
The Nuclear Regulatory Commission (NRC) is an independent agency of the United States government tasked with protecting public health and safety related to nuclear energy. Established by the Energy Reorganization Act of 1974, the NRC began operat ...
(NRC) has jurisdiction over a relatively narrow spectrum of radiation, and the
Environmental Protection Agency
A biophysical environment is a biotic and abiotic surrounding of an organism or population, and consequently includes the factors that have an influence in their survival, development, and evolution. A biophysical environment can vary in scale f ...
(EPA) has jurisdiction over NORM. Since no federal entity has implemented NORM regulations, NORM is variably regulated by the states.
United Kingdom
In the UK regulation is via the Environmental Permitting (England and Wales) Regulations 2010.
This defines two types of NORM activity:
*Type 1 NORM industrial activity means:
(a) the production and use of thorium, or thorium compounds, and the production of products where thorium is deliberately added; or
(b) the production and use of uranium or uranium compounds, and the production of products where uranium is deliberately added
* Type 2 NORM industrial activity means:
(a) the extraction, production and use of rare earth elements and rare earth element alloys;
(b) the mining and processing of ores other than uranium ore;
(c) the production of oil and gas;
(d) the removal and management of radioactive scales and precipitates from equipment associated with industrial activities;
(e) any industrial activity utilising phosphate ore;
(f) the manufacture of titanium dioxide pigments;
(g) the extraction and refining of zircon and manufacture of zirconium compounds;
(h) the production of tin, copper, aluminium, zinc, lead and iron and steel;
(i) any activity related to coal mine de-watering plants;
(j) china clay extraction;
(k) water treatment associated with provision of drinking water;
or
(l) The remediation of contamination from any type 1 NORM industrial activity or any of the activities listed above.
An activity which involves the processing of radionuclides of natural terrestrial or cosmic origin for their radioactive, fissile or fertile properties is not a type 1 NORM industrial activity or a type 2 NORM industrial activity.
[Guidance to Environmental Permitting (England and Wales) Regulations (EPR) 2010]
See also
*
Background radiation, ionizing radiation constantly present in the natural environment of the Earth
*
Environmental radioactivity
References
External links
North Dakota Department of HealthNORM Technology Connection Interstate Oil and Gas Compact Commission
Radiation Quick Reference Guide Domestic Nuclear Detection Office
Naturally Occurring Radioactive Materialsfrom the
World Nuclear Association
World Nuclear Association is the international organization that promotes nuclear power and supports the companies that comprise the global nuclear industry. Its members come from all parts of the nuclear fuel cycle, including uranium mining, ur ...
UK guidance on Radioactive Substances Regulation For the Environmental Permitting (England and Wales) Regulations 2010:Defra
Radioactive waste
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