CESIUM COMPOUNDS:
Nuclear Power Plant Emissions
Artificial Pollution Sources :
The production and use of cesium compounds may result in their release to the
environment through various waste streams(SRC). However, there are relatively
few commercial uses for cesium compounds(1,2). Cesium iodide and cesium fluoride
are used in scintillation counters(1). Recently, cesium compounds have been
employed as catalysts in organic synthesis(2). Cesium hydroxide is used as a
catalyst in the polymerization of cyclic siloxanes, for electrolytes in storage
batteries, and in color photography(3). Cesium bromide is used in X-ray
fluorescent screens, spectrometer prisms, and absorption-cell windows(4). Cesium
carbonate is used as a catalyst in ethylene oxide polymerization; in coating for
spatter-free welding of steel in carbon dioxide; in oxide cathode(4). Cesium
nitrate is used in prisms for infrared spectroscopy; in x-ray fluorescent
screens, and in scintillation counters(4). Cesium nitrate is used in the
preparation of other cesium salts(4). Of much greater concern is the release of
radioactive forms of cesium (e.g., cesium-137 and cesium-134) to the
environment(5). These and other radioactive isotopes were released to the
environment as a result of atmospheric testing of nuclear weapons carried out
between 1945 to 1980 and accidents that occurred at nuclear power plants (e.g.,
Chernobyl nuclear power plant in 1986 and Windscale Nuclear Weapons Facility,
United Kingdom in 1957)(5). Small amounts of cesium-137 and cesium-134 are also
released in the airborne and liquid effluents during the normal operation of
nuclear power plants(5).
Environmental Fate/Exposure Summary :
Cesium is the rarest of the naturally occurring alkali metals. Its compounds are
correspondingly rare. Granites contain about 1 ppm cesium and sedimentary rocks
contain approximately 4 ppm cesium. The most common commercial source of cesium
is pollucite which contains between 5-32% cesium oxide. The production and use
of cesium compounds may result in their release to the environment through
various waste streams. However, there are relatively few commercial uses for
cesium compounds. Cesium iodide and cesium fluoride are used in scintillation
counters. Recently, cesium compounds have been employed as catalysts in organic
synthesis. Radioactive isotopes of cesium (cesium-134 and cesium-137) have been
released to the environment by human activities such as the atmospheric testing
of nuclear weapons (from 1945 to 1980) and accidents at nuclear power plants
(e.g., at Chernobyl, Ukraine in 1986). If released to air, cesium compounds are
deposited on land and water via wet and dry deposition; deposited cesium
compounds may be re-suspended into the atmosphere from soil and dust by the
wind. If released to soil, cesium compounds have low mobilities and do not
migrate below a depth of 40 cm. The majority of cesium(I) ions are retained in
the upper 20 cm of the soil surface. Clay and zeolite minerals strongly bind
cesium cations irreversibly. Soils rich in organic matter will also adsorb
cesium(I) ions. However in these soils, cesium compounds are readily
exchangeable and highly available for plant uptake. If released into water,
cesium compounds are very water soluble and exist primarily as cesium(I) cations.
Because most cesium compounds are ionic, they will not volatilize from water
surfaces. Most cesium compounds released to water adsorb to suspended solids in
the water column and ultimately are deposited in sediments. Cesium compounds
bioconcentrate and have been shown to bioaccumulate in both terrestrial and
aquatic food chains. For example, mean BCF values of 92, 58, 39, and 150 were
reported for cesium-137 in cod, haddock, plaice, and whiting, respectively.
Occupational exposure to cesium compounds occur primarily through inhalation and
dermal contact at workplaces where pollucite is mined or cesium compounds are
manufactured or used. General population exposure to cesium occurs by ingestion
of food and drinking water, by inhalation of ambient air, and dermal contact
with cesium compounds in soil. Current exposure of the general population of the
US to radioactive cesium-134 and cesium-137 is expected to be low since
atmospheric testing of nuclear weapons has been discontinued for many years and
Chernobyl-related fallout was low in the US. However, exposure is possible from
contaminated ground/surface waters at DOE sites, resulting from past defense
related efforts at these sites. (SRC)
Effluent Concentrations :
Cesium was detected at concns of 10.8 and 6.11 mg/cu m in the effluent of a
coal-burning power plant in the western United States(1) and has been identified
in the fly ash from municipal incinerators(2,3). Fly ash from five municipal
waste incinerators in the US contained cesium at concns of 2,100 to 12,000
ppm(4).
Analytic Laboratory Methods :
Analyte: cesium; matrix: ambient particulate matter; procedure: proton induced
x-ray emission (PIXE) spectroscopy; detection limit: 25.3 ng/cu m. /Cesium/
Soil Adsorption/Mobility :
In soil, cesium has low mobility and usually does not migrate below a depth of
40 cm. The majority of cesium ions are retained in the upper 20 cm of the soil
surface(1-3). For example, vertical migration patterns of cesium-137 in four
agricultural soils from southern Chile indicated that approx 90% of the applied
cesium was retained in the top 40 cm of soil(4). In one soil, essentially 100%
was bound in the upper 10 cm(4). Migration rates of radiocesium were derived
from depth distribution profiles and were in the range of 0.11 to 0.29 cm/yr(4).
No correlations were observed for other soil properties such as pH, water
content, cation exchange capacity, and exchangeable calcium. Other studies
report that clay and zeolite minerals strongly bind cesium cations and therefore
reduce the bioavailability of cesium and the uptake in plants by irreversibly
binding cesium in interlayer positions of the clay particles(5). Experiments
conducted by growing plants in a peat soil showed that the introduction of
zeolites into the soil-plant system decreased the uptake of cesium-134 in plants
by a factor of eight(6). The low hydration energy of cesium cations is primarily
responsible for their selective sorption and fixation by clays and zeolites(7).
Soils rich in organic matter adsorb cesium(8). However, the cesium adsorbed in
the organic fraction is readily exchangeable and highly available for plant
uptake(8). Regions in Venezuela, Brazil, and Russia where the soils are peaty or
podzolic, the mobility of cesium is considerably greater than in other
soils(9,10).
Environmental Fate :
TERRESTRIAL FATE: In soil, cesium has low mobility and usually does not migrate
below a depth of 40 cm. The majority of cesium ions are retained in the upper 20
cm of the soil surface(1-3). For example, vertical migration patterns of
cesium-137 in four agricultural soils from southern Chile indicated that approx
90% of the applied cesium was retained in the top 40 cm of soil(4). In one soil,
essentially 100% was bound in the upper 10 cm(4). Other studies report that clay
and zeolite minerals strongly bind cesium cations and therefore reduce the
bioavailability of cesium and the uptake in plants by irreversibly binding
cesium in interlayer positions of the clay particles(5). The low hydration
energy of cesium cations is primarily responsible for their selective sorption
and fixation by clays and zeolites(6). Soils rich in organic matter adsorb
cesium(7). However, the cesium adsorbed in the organic fraction is readily
exchangeable and highly available for plant uptake(7).
Disposal Methods :
SRP: The most favorable course of action is to use an alternative chemical
product with less inherent propensity for occupational exposure or environmental
contamination. Recycle any unused portion of the material for its approved use
or return it to the manufacturer or supplier. Ultimate disposal of the chemical
must consider: the material's impact on air quality; potential migration in soil
or water; effects on animal, aquatic, and plant life; and conformance with
environmental and public health regulations.
Plant Concentrations :
The median concn of cesium in poplar leaves collected in Bulgaria was reported
as 75 ng/g, while concn in land plants ranged from 30 to 440 ng/g(1).
MORE ABOUT HEALTH EFFECTS
CESIUM
COMPOUNDS
CASRN: NO CAS RN
This record contains information on the general toxicity and environmental
fate of cesium ions and inorganic and organic cexium compounds, including
statements in the literature referenced to cesium compounds and cesium salts.
For compound-specific information, refer to the appropriate individual records
as listed in the RELATED HSDB RECORDS field; for information on the metal
itself, refer to the CESIUM, ELEMENTAL record, for information on the
radiological aspects of cobalt and its compounds, refer to the CESIUM,
RADIOACTIVE record. For general toxicological, safety and handling, and
environmental information on ionizing radiation emitted from chemical sources
including uranium, refer to the IONIZING
RADIATION RECORD
For other data, click on the Table of Contents
Human Toxicity Excerpts:
/SIGNS AND SYMPTOMS/ Potential symptoms of overexposure are irritation of eyes,
skin, upper respiratory tract; eye and skin burns. /Cesium hydroxide/
Skin, Eye and Respiratory Irritations:
/Cesium hydroxide/ is extremely hygroscopic and is an extraordinarily strong
base, extracting water from the moist, superficial surfaces of the body and,
hence, acting as a strong corrosive when in the solid form. /Cesium hydroxide/
Probable Routes of Human Exposure:
General population exposure to cesium occurs by ingestion of food and drinking
water, by inhalation of ambient air, and dermal contact with cesium in soil(1).
Occupational exposure to cesium occurs primarily through inhalation and dermal
contact at workplaces where pollucite is mined or cesium compounds are
manufactured or used(1). The National Occupation Exposure Survey (NOES)
conducted by the National Institute for Occupational Safety (NIOSH) from 1981 to
1983 has estimated that 16,461 workers (4,276 of these were female) were
potentially exposed to cesium and cesium compounds in the United States(2). The
median concn of cesium in the lungs of metal workers in northern Sweden was
0.016 ug/g and was lower than the median concn of 0.021 ug/g for a control group
that was not occupationally exposed(3). The range of cesium concns in lung
tissue of coal miners from the United Kingdom was 0.07-0.91 ug/g(3).
Body Burden:
The National Health and Nutritional Examination Survey (NHANES), conducted by
the Centers for Disease Control (CDC), reported that the geometric mean concn of
cesium in the urine of 1,006 US residents was 4.7 ug/L in 1999(1).
Probable Routes of Human Exposure:
General population exposure to cesium occurs by ingestion of food and drinking
water, by inhalation of ambient air, and dermal contact with cesium in soil(1).
Occupational exposure to cesium occurs primarily through inhalation and dermal
contact at workplaces where pollucite is mined or cesium compounds are
manufactured or used(1). The National Occupation Exposure Survey (NOES)
conducted by the National Institute for Occupational Safety (NIOSH) from 1981 to
1983 has estimated that 16,461 workers (4,276 of these were female) were
potentially exposed to cesium and cesium compounds in the United States(2). The
median concn of cesium in the lungs of metal workers in northern Sweden was
0.016 ug/g and was lower than the median concn of 0.021 ug/g for a control group
that was not occupationally exposed(3). The range of cesium concns in lung
tissue of coal miners from the United Kingdom was 0.07-0.91 ug/g(3).
Body Burden:
The National Health and Nutritional Examination Survey (NHANES), conducted by
the Centers for Disease Control (CDC), reported that the geometric mean concn of
cesium in the urine of 1,006 US residents was 4.7 ug/L in 1999(1).
Skin, Eye and Respiratory Irritations:
/Cesium hydroxide/ is extremely hygroscopic and is an extraordinarily strong
base, extracting water from the moist, superficial surfaces of the body and,
hence, acting as a strong corrosive when in the solid form. /Cesium hydroxide/
All of the above is
directly from http://toxnet.nlm.nih.gov/