Actinides in the environment
Encyclopedia
Actinides in the environment refer to the sources, environmental behaviour and effects of actinide
s in Earth's environment
. Environmental radioactivity
is not limited solely to actinides; non-actinides such as radon and radium are of note.
insoluble actinide compounds such as high-fired uranium dioxide
and mixed oxide (MOX) fuel
will pass through the digestive system with little effect if since they cannot dissolve and be absorbed by the body. Inhaled actinide compounds, however, will be more damaging as they remain in the lungs and irradiate the lung tissue.
Ingested Low-fired oxides and soluble salts such as nitrate
can be absorbed into the blood stream. If they are inhaled then it is possible for the solid to dissolve and leave the lungs. Hence the dose to the lungs will be lower for the soluble form.
and radium
are not actinides—they are both radioactive daughters from the decay of uranium. Aspects of their biology and environmental behaviour is discussed at radium in the environment
.
, a large amount of thorium
ore can be found in the form of monazite
in placer deposit
s of the Western and Eastern coastal dune
sand
s, particularly in the Tamil Nadu
coastal areas. The residents of this area are exposed to a naturally occurring radiation dose ten times higher than the worldwide average.
s, where it is about three times more abundant than uranium, and is about as common as lead
. Soil commonly contains an average of around 6 parts per million (ppm) of thorium. Thorium occurs in several mineral
s, the most common being the rare earth-thorium-phosphate mineral, monazite
, which contains up to about 12% thorium oxide. There are substantial deposits in several countries. 232Th decays very slowly (its half-life
is about three times the age of the earth) but other thorium isotope
s occur in the thorium and uranium decay chains. Most of these are short-lived and hence much more radioactive than 232Th, though on a mass basis they are negligible.
cancer
. In the past thoria (thorium dioxide
) was used as a contrast agent for medical X-ray radiography but its use has been discontinued. It was sold under the name Thorotrast
.
is a natural metal which is widely found. It is present in almost all soils and it is more plentiful than antimony
, beryllium
, cadmium
, gold
, mercury
, silver
, or tungsten
and is about as abundant as arsenic
or molybdenum
. Significant concentrations of uranium occur in some substances such as phosphate
rock deposits, and minerals such as lignite
, and monazite sands in uranium-rich ore
s (it is recovered commercially from these sources).
Seawater contains about 3.3 parts per billion of uranium by weight as uranium(VI) forms soluble carbonate
complexes. The extraction of uranium from seawater has been considered as a means of obtaining the element. Because of the very low specific activity of uranium the chemical effects of it upon living things can often outweigh the effects of its radioactivity. Additional uranium has been added to the environment in some locations as a result of the nuclear fuel cycle
and the use of depleted uranium
in munitions.
has a high affinity for soil. However, it is relatively mobile over the long term, and diffusion of neptunium-237 in groundwater is a major issue in designing a deep geological repository
for permanent storage of spent nuclear fuel
. 237Np has a halflife of 2.144 million years, so it is a long-term problem; but its halflife is still much shorter than those of uranium-238
, uranium-235
, or uranium-236
, and 237Np therefore has higher specific activity
than those nuclides.
in the environment has several sources. These include:
dioxide (plutonyl) core (PuO2). In the environment, this plutonyl core readily complexes with carbonate
as well as other oxygen moieties (OH-, NO2-, NO3-, and SO4−2) to form charged complexes which can be readily mobile with low affinities to soil.
PuO2 formed from neutralizing highly acidic nitric acid solutions tends to form polymeric PuO2 which is resistant to complexation. Plutonium also readily shifts valences between the +3, +4, +5 and +6 states. It is common for some fraction of plutonium in solution to exist in all of these states in equilibrium.
Plutonium is known to bind to soil particles very strongly, see above for a X-ray spectroscopic study of plutonium in soil and concrete
. While caesium
has very different chemistry to the actinides, it is well known that both caesium and many of the actinides bind strongly to the minerals in soil. Hence it has been possible to use 134Cs labeled soil to study the migration of Pu and Cs is soils. It has been shown that colloid
al transport processes control the migration of Cs (and will control the migration of Pu) in the soil at the Waste Isolation Pilot Plant
.
often enters landfills from discarded smoke detector
s. The rules associated with the disposal of smoke detectors are very relaxed in most municipalities. For instance in the UK it is permissible to dispose of an americium containing smoke detector by placing it in the dustbin with normal household rubbish, but each dustbin worth of rubbish is limited to only containing one smoke detector.
In France
a truck
transporting 900 smoke detectors had been reported to have caught fire, it is claimed that this led to a release of americium into the environment. In the U.S., the "Radioactive Boy Scout" David Hahn
was able to buy thousands of smoke detectors at remainder prices and concentrate the americium from them.
There have been cases of humans being contaminated with americium, the worst case being that of Harold McCluskey
. It is interesting to note that Harold McCluskey did not die of cancer but of heart disease
(which he had before the accident). It is likely that the medical care which he was given saved his life; because of the difference in the chemistry of americium (the +3 oxidation state
is very stable) to plutonium (where the +4 state can form in the human body) the americium has very different biochemistry to plutonium.
The most common isotope americium-241 decays (halflife 431 years) to neptunium-237 which has a much longer halflife, so in the long term, the issues discussed above for neptunium apply.
Actinide
The actinide or actinoid series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium.The actinide series derives its name from the group 3 element actinium...
s in Earth's environment
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
. Environmental radioactivity
Environmental radioactivity
Environmental radioactivity is produced by radioactive materials in the human environment. While some radioisotopes, such as strontium-90 and technetium-99 , are only found on Earth as a result of human activity, and some, like potassium-40 , are only present due to natural processes, a few...
is not limited solely to actinides; non-actinides such as radon and radium are of note.
Inhalation versus ingestion
Generally, ingestedIngestion
Ingestion is the consumption of a substance by an organism. In animals, it normally is accomplished by taking in the substance through the mouth into the gastrointestinal tract, such as through eating or drinking...
insoluble actinide compounds such as high-fired uranium dioxide
Uranium dioxide
Uranium dioxide or uranium oxide , also known as urania or uranous oxide, is an oxide of uranium, and is a black, radioactive, crystalline powder that naturally occurs in the mineral uraninite. It is used in nuclear fuel rods in nuclear reactors. A mixture of uranium and plutonium dioxides is used...
and mixed oxide (MOX) fuel
MOX fuel
Mixed oxide fuel, commonly referred to as MOX fuel, is nuclear fuel that contains more than one oxide of fissile material. MOX fuel contains plutonium blended with natural uranium, reprocessed uranium, or depleted uranium. MOX fuel is an alternative to the low-enriched uranium fuel used in the...
will pass through the digestive system with little effect if since they cannot dissolve and be absorbed by the body. Inhaled actinide compounds, however, will be more damaging as they remain in the lungs and irradiate the lung tissue.
Ingested Low-fired oxides and soluble salts such as nitrate
Nitrate
The nitrate ion is a polyatomic ion with the molecular formula NO and a molecular mass of 62.0049 g/mol. It is the conjugate base of nitric acid, consisting of one central nitrogen atom surrounded by three identically-bonded oxygen atoms in a trigonal planar arrangement. The nitrate ion carries a...
can be absorbed into the blood stream. If they are inhaled then it is possible for the solid to dissolve and leave the lungs. Hence the dose to the lungs will be lower for the soluble form.
Radon and radium in the environment
RadonRadon
Radon is a chemical element with symbol Rn and atomic number 86. It is a radioactive, colorless, odorless, tasteless noble gas, occurring naturally as the decay product of uranium or thorium. Its most stable isotope, 222Rn, has a half-life of 3.8 days...
and radium
Radium
Radium is a chemical element with atomic number 88, represented by the symbol Ra. Radium is an almost pure-white alkaline earth metal, but it readily oxidizes on exposure to air, becoming black in color. All isotopes of radium are highly radioactive, with the most stable isotope being radium-226,...
are not actinides—they are both radioactive daughters from the decay of uranium. Aspects of their biology and environmental behaviour is discussed at radium in the environment
Radium in the environment
- Radium in quack medicine :See the story of Eben Byers for details of one very nasty case which involved a product called Radithor which contained 1 uCi of 226Ra and 1 uCi of 228Ra per bottle...
.
Thorium in the environment
In IndiaIndia
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
, a large amount of thorium
Thorium
Thorium is a natural radioactive chemical element with the symbol Th and atomic number 90. It was discovered in 1828 and named after Thor, the Norse god of thunder....
ore can be found in the form of monazite
Monazite
Monazite is a reddish-brown phosphate mineral containing rare earth metals. It occurs usually in small isolated crystals. There are actually at least four different kinds of monazite, depending on relative elemental composition of the mineral:...
in placer deposit
Placer deposit
In geology, a placer deposit or placer is an accumulation of valuable minerals formed by gravity separation during sedimentary processes. The name is from the Spanish word placer, meaning "alluvial sand". Placer mining is an important source of gold, and was the main technique used in the early...
s of the Western and Eastern coastal dune
Dune
In physical geography, a dune is a hill of sand built by wind. Dunes occur in different forms and sizes, formed by interaction with the wind. Most kinds of dunes are longer on the windward side where the sand is pushed up the dune and have a shorter "slip face" in the lee of the wind...
sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
s, particularly in the Tamil Nadu
Tamil Nadu
Tamil Nadu is one of the 28 states of India. Its capital and largest city is Chennai. Tamil Nadu lies in the southernmost part of the Indian Peninsula and is bordered by the union territory of Pondicherry, and the states of Kerala, Karnataka, and Andhra Pradesh...
coastal areas. The residents of this area are exposed to a naturally occurring radiation dose ten times higher than the worldwide average.
Occurrence
Thorium is found at low levels in most rocks and soilSoil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
s, where it is about three times more abundant than uranium, and is about as common as lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
. Soil commonly contains an average of around 6 parts per million (ppm) of thorium. Thorium occurs in several mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
s, the most common being the rare earth-thorium-phosphate mineral, monazite
Monazite
Monazite is a reddish-brown phosphate mineral containing rare earth metals. It occurs usually in small isolated crystals. There are actually at least four different kinds of monazite, depending on relative elemental composition of the mineral:...
, which contains up to about 12% thorium oxide. There are substantial deposits in several countries. 232Th decays very slowly (its half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...
is about three times the age of the earth) but other thorium isotope
Isotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...
s occur in the thorium and uranium decay chains. Most of these are short-lived and hence much more radioactive than 232Th, though on a mass basis they are negligible.
Effects in humans
Thorium has been linked to liverLiver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
. In the past thoria (thorium dioxide
Thorium dioxide
Thorium dioxide , also called thorium oxide is a white, crystalline powder. It was formerly known as thoria or thorina. It is produced mainly as a by-product of lanthanide and uranium production.[1]...
) was used as a contrast agent for medical X-ray radiography but its use has been discontinued. It was sold under the name Thorotrast
Thorotrast
Thorotrast is a suspension containing particles of the radioactive compound thorium dioxide, ThO2, used as a contrast medium in X-ray diagnostics in the 1930s and 40s ....
.
Uranium in the environment
UraniumUranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
is a natural metal which is widely found. It is present in almost all soils and it is more plentiful than antimony
Antimony
Antimony is a toxic chemical element with the symbol Sb and an atomic number of 51. A lustrous grey metalloid, it is found in nature mainly as the sulfide mineral stibnite...
, beryllium
Beryllium
Beryllium is the chemical element with the symbol Be and atomic number 4. It is a divalent element which occurs naturally only in combination with other elements in minerals. Notable gemstones which contain beryllium include beryl and chrysoberyl...
, cadmium
Cadmium
Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Similar to zinc, it prefers oxidation state +2 in most of its compounds and similar to mercury it shows a low...
, gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...
, mercury
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
, silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
, or tungsten
Tungsten
Tungsten , also known as wolfram , is a chemical element with the chemical symbol W and atomic number 74.A hard, rare metal under standard conditions when uncombined, tungsten is found naturally on Earth only in chemical compounds. It was identified as a new element in 1781, and first isolated as...
and is about as abundant as arsenic
Arsenic
Arsenic is a chemical element with the symbol As, atomic number 33 and relative atomic mass 74.92. Arsenic occurs in many minerals, usually in conjunction with sulfur and metals, and also as a pure elemental crystal. It was first documented by Albertus Magnus in 1250.Arsenic is a metalloid...
or molybdenum
Molybdenum
Molybdenum , is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin Molybdaenum, from Ancient Greek , meaning lead, itself proposed as a loanword from Anatolian Luvian and Lydian languages, since its ores were confused with lead ores...
. Significant concentrations of uranium occur in some substances such as phosphate
Phosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
rock deposits, and minerals such as lignite
Lignite
Lignite, often referred to as brown coal, or Rosebud coal by Northern Pacific Railroad,is a soft brown fuel with characteristics that put it somewhere between coal and peat...
, and monazite sands in uranium-rich ore
Ore
An ore is a type of rock that contains minerals with important elements including metals. The ores are extracted through mining; these are then refined to extract the valuable element....
s (it is recovered commercially from these sources).
Seawater contains about 3.3 parts per billion of uranium by weight as uranium(VI) forms soluble carbonate
Carbonate
In chemistry, a carbonate is a salt of carbonic acid, characterized by the presence of the carbonate ion, . The name may also mean an ester of carbonic acid, an organic compound containing the carbonate group C2....
complexes. The extraction of uranium from seawater has been considered as a means of obtaining the element. Because of the very low specific activity of uranium the chemical effects of it upon living things can often outweigh the effects of its radioactivity. Additional uranium has been added to the environment in some locations as a result of the nuclear fuel cycle
Nuclear fuel cycle
The nuclear fuel cycle, also called nuclear fuel chain, is the progression of nuclear fuel through a series of differing stages. It consists of steps in the front end, which are the preparation of the fuel, steps in the service period in which the fuel is used during reactor operation, and steps in...
and the use of depleted uranium
Depleted uranium
Depleted uranium is uranium with a lower content of the fissile isotope U-235 than natural uranium . Uses of DU take advantage of its very high density of 19.1 g/cm3...
in munitions.
Neptunium in the environment
Like plutonium, neptuniumNeptunium
Neptunium is a chemical element with the symbol Np and atomic number 93. A radioactive metal, neptunium is the first transuranic element and belongs to the actinide series. Its most stable isotope, 237Np, is a by-product of nuclear reactors and plutonium production and it can be used as a...
has a high affinity for soil. However, it is relatively mobile over the long term, and diffusion of neptunium-237 in groundwater is a major issue in designing a deep geological repository
Deep geological repository
A deep geological repository is a nuclear waste repository excavated deep within a stable geologic environment...
for permanent storage of spent nuclear fuel
Spent nuclear fuel
Spent nuclear fuel, occasionally called used nuclear fuel, is nuclear fuel that has been irradiated in a nuclear reactor...
. 237Np has a halflife of 2.144 million years, so it is a long-term problem; but its halflife is still much shorter than those of uranium-238
Uranium-238
Uranium-238 is the most common isotope of uranium found in nature. It is not fissile, but is a fertile material: it can capture a slow neutron and after two beta decays become fissile plutonium-239...
, uranium-235
Uranium-235
- References :* .* DOE Fundamentals handbook: Nuclear Physics and Reactor theory , .* A piece of U-235 the size of a grain of rice can produce energy equal to that contained in three tons of coal or fourteen barrels of oil. -External links:* * * one of the earliest articles on U-235 for the...
, or uranium-236
Uranium-236
- See also :* Depleted uranium* Uranium market* Nuclear reprocessing* United States Enrichment Corporation* Nuclear fuel cycle* Nuclear power-External links:* *...
, and 237Np therefore has higher specific activity
Specific activity
In nuclear sciences and technologies, "activity" is the SI quantity related to the phenomenon of natural and artificial radioactivity. The SI unit of "activity" is becquerel, Bq, while that of "specific activity" is Bq/kg. The old unit of "activity" was curie, Ci, while that of "specific activity"...
than those nuclides.
Sources
PlutoniumPlutonium
Plutonium is a transuranic radioactive chemical element with the chemical symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, forming a dull coating when oxidized. The element normally exhibits six allotropes and four oxidation...
in the environment has several sources. These include:
- Atomic batteries
- In space
- In pacemakers
- Bomb detonations
- Bomb safety trials
- Nuclear accidents (such as Chernobyl)
- Nuclear crime
- Nuclear fuel cycle
Environmental chemistry
Plutonium, like other actinides, readily forms a plutoniumPlutonium
Plutonium is a transuranic radioactive chemical element with the chemical symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, forming a dull coating when oxidized. The element normally exhibits six allotropes and four oxidation...
dioxide (plutonyl) core (PuO2). In the environment, this plutonyl core readily complexes with carbonate
Carbonate
In chemistry, a carbonate is a salt of carbonic acid, characterized by the presence of the carbonate ion, . The name may also mean an ester of carbonic acid, an organic compound containing the carbonate group C2....
as well as other oxygen moieties (OH-, NO2-, NO3-, and SO4−2) to form charged complexes which can be readily mobile with low affinities to soil.
- PuO2(CO3)1−2
- PuO2(CO3)2−4
- PuO2(CO3)3−6
PuO2 formed from neutralizing highly acidic nitric acid solutions tends to form polymeric PuO2 which is resistant to complexation. Plutonium also readily shifts valences between the +3, +4, +5 and +6 states. It is common for some fraction of plutonium in solution to exist in all of these states in equilibrium.
Plutonium is known to bind to soil particles very strongly, see above for a X-ray spectroscopic study of plutonium in soil and concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
. While caesium
Caesium
Caesium or cesium is the chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-gold alkali metal with a melting point of 28 °C , which makes it one of only five elemental metals that are liquid at room temperature...
has very different chemistry to the actinides, it is well known that both caesium and many of the actinides bind strongly to the minerals in soil. Hence it has been possible to use 134Cs labeled soil to study the migration of Pu and Cs is soils. It has been shown that colloid
Colloid
A colloid is a substance microscopically dispersed evenly throughout another substance.A colloidal system consists of two separate phases: a dispersed phase and a continuous phase . A colloidal system may be solid, liquid, or gaseous.Many familiar substances are colloids, as shown in the chart below...
al transport processes control the migration of Cs (and will control the migration of Pu) in the soil at the Waste Isolation Pilot Plant
Waste Isolation Pilot Plant
The Waste Isolation Pilot Plant, or WIPP, is the world's third deep geological repository licensed to permanently dispose of transuranic radioactive waste for 10,000 years that is left from the research and production of nuclear weapons...
.
Americium in the environment
AmericiumAmericium
Americium is a synthetic element that has the symbol Am and atomic number 95. This transuranic element of the actinide series is located in the periodic table below the lanthanide element europium, and thus by analogy was named after another continent, America.Americium was first produced in 1944...
often enters landfills from discarded smoke detector
Smoke detector
A smoke detector is a device that detects smoke, typically as an indicator of fire. Commercial, industrial, and mass residential devices issue a signal to a fire alarm system, while household detectors, known as smoke alarms, generally issue a local audible and/or visual alarm from the detector...
s. The rules associated with the disposal of smoke detectors are very relaxed in most municipalities. For instance in the UK it is permissible to dispose of an americium containing smoke detector by placing it in the dustbin with normal household rubbish, but each dustbin worth of rubbish is limited to only containing one smoke detector.
In France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
a truck
Truck
A truck or lorry is a motor vehicle designed to transport cargo. Trucks vary greatly in size, power, and configuration, with the smallest being mechanically similar to an automobile...
transporting 900 smoke detectors had been reported to have caught fire, it is claimed that this led to a release of americium into the environment. In the U.S., the "Radioactive Boy Scout" David Hahn
David Hahn
David Charles Hahn , also called the "Radioactive Boy Scout" or the "Nuclear Boy Scout", is an American who attempted to build a homemade breeder nuclear reactor in 1994, at age 17. A scout in the Boy Scouts of America, Hahn conducted his experiments in secret in a backyard shed at his mother's...
was able to buy thousands of smoke detectors at remainder prices and concentrate the americium from them.
There have been cases of humans being contaminated with americium, the worst case being that of Harold McCluskey
Harold McCluskey
Harold R. McCluskey was a chemical operations technician at the Hanford Plutonium Finishing Plant located in Washington state who is known for having survived, on April 24, 1976, exposure to the highest dose of americium radiation ever recorded...
. It is interesting to note that Harold McCluskey did not die of cancer but of heart disease
Heart disease
Heart disease, cardiac disease or cardiopathy is an umbrella term for a variety of diseases affecting the heart. , it is the leading cause of death in the United States, England, Canada and Wales, accounting for 25.4% of the total deaths in the United States.-Types:-Coronary heart disease:Coronary...
(which he had before the accident). It is likely that the medical care which he was given saved his life; because of the difference in the chemistry of americium (the +3 oxidation state
Oxidation state
In chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic. Oxidation states are typically represented by...
is very stable) to plutonium (where the +4 state can form in the human body) the americium has very different biochemistry to plutonium.
The most common isotope americium-241 decays (halflife 431 years) to neptunium-237 which has a much longer halflife, so in the long term, the issues discussed above for neptunium apply.
See also
- Uranium in the environmentUranium in the environmentUranium in the environment refers to the science of the sources, environmental behaviour, and effects of uranium on humans and other animals. Uranium is weakly radioactive and remains so because of its long physical half-life...
- Radium in the environmentRadium in the environment- Radium in quack medicine :See the story of Eben Byers for details of one very nasty case which involved a product called Radithor which contained 1 uCi of 226Ra and 1 uCi of 228Ra per bottle...
- Background radiationBackground radiationBackground radiation is the ionizing radiation constantly present in the natural environment of the Earth, which is emitted by natural and artificial sources.-Overview:Both Natural and human-made background radiation varies by location....
Further reading
- Hala, Jiri, and James D. Navratil. Radioactivity, Ionizing Radiation and Nuclear Energy. Konvoj: Brno, Czech Republic, 2003. ISBN 80-7302-053-X.
External links
- Royal Society for Chemistry - Why do mechanisms matter in radioactive waste management?
- Federation of American Scientists - Spectroscopies for Environmental Studies of Actinide Species