Erionite
Encyclopedia
Erionite is a naturally occurring fibrous mineral that belongs to a group of minerals called zeolites. It usually is found in volcanic ash that has been altered by weathering and ground water. Erionite forms brittle, wool-like fibrous masses in the hollows of rock formations and has an internal molecular structure similar to chabazite
. Some properties of erionite are similar to the properties of asbestos
; however, erionite is not currently regulated by the U.S. Environmental Protection Agency as one of the six asbestos fibers. Erionite was first described by A.S. Eakle in 1898, as white woolly fibrous masses in cavities in rhyolite
lava near Durkee
, Oregon
. It was originally thought to be another relatively rare zeolite named offretite, which is very similar to erionite in appearance and chemical composition.
capacity.
as a Group 1 Carcinogen. The prevalence of malignant pleural and peritoneal mesothelioma
due to erionite exposure in the Central Anatolia Region
is very high. Descriptive studies have reported an excess of mortality from mesothelioma in individuals living in three Turkish villages where there was chronic exposure to erionite; only two cases of mesothelioma occurred in the control village, both in women born elsewhere. An excess of lung cancer also was reported in two of the three villages contaminated with erionite. Respirable erionite fibers were detected in air samples collected from the affected villages, and lung tissue samples collected from mesothelioma cases contained erionite fibers. A higher proportion of ferruginous (iron-containing) bodies with a zeolite core were found in inhabitants of the contaminated villages than of those from the two control villages. Erionite is reportedly present in the local volcanic
tuff
. There is sufficient evidence of carcinogenicity of erionite in experimental animals. Rats exposed to erionite by inhalation or injection (intrapleural or intraperitoneal) and mice exposed by intraperitoneal injection had high incidences of mesotheliomas.
began a study of possible erionite exposure among residents. Erionite has also been identified in samples from the Tertiary Arikaree Formation in southeast Montana and northwest South Dakota.
Potential occupational exposure to erionite occurs during the production and mining of other zeolites. In the past, occupational exposure occurred from erionite mining and production operation.
Erionite also was reported to be a minor component in some commercial zeolites. Therefore, the use of other zeolites may result in potential exposure to erionite for the workers and the general population who use the zeolites in a variety of processes and products. Total dust exposures for miners in an open-pit zeolite mine that contained some erionite in Arizona ranged from 0.01 to 13.7 mg/m3; respirable dust in the mining area was 0.01 to 1.4 mg/m3.
Erionite is held responsible for the high incidence of lung cancer
, asbestosis
, pleural mesothelioma and other lung problems in the Turkish village of Tuzkoy near Nevsehir in the popular tourist region of Cappadoccia
Chabazite
Chabazite is a tectosilicate mineral of the zeolite group, closely related to gmelinite, with formula Al2Si4O12·6H2O. Recognized varieties include Chabazite-Ca, Chabazite-K, Chabazite-Na, and Chabazite-Sr, depending on the prominence of the indicated cation.Chabazite crystallizes in the triclinic...
. Some properties of erionite are similar to the properties of asbestos
Asbestos
Asbestos is a set of six naturally occurring silicate minerals used commercially for their desirable physical properties. They all have in common their eponymous, asbestiform habit: long, thin fibrous crystals...
; however, erionite is not currently regulated by the U.S. Environmental Protection Agency as one of the six asbestos fibers. Erionite was first described by A.S. Eakle in 1898, as white woolly fibrous masses in cavities in rhyolite
Rhyolite
This page is about a volcanic rock. For the ghost town see Rhyolite, Nevada, and for the satellite system, see Rhyolite/Aquacade.Rhyolite is an igneous, volcanic rock, of felsic composition . It may have any texture from glassy to aphanitic to porphyritic...
lava near Durkee
Durkee, Oregon
Durkee is an unincorporated community in Baker County, Oregon, United States. Although it is unincorporated, it has a post office with the ZIP code of 97905. Durkee lies at the Vandercar Road exit of Interstate 84....
, Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
. It was originally thought to be another relatively rare zeolite named offretite, which is very similar to erionite in appearance and chemical composition.
Properties
The chemical composition of erionite is approximately represented by the formula (Na2,K2,Ca)2Al4Si14O36·15H2O. It can be differentiated into Erionite-Na, Erionite-K, and Erionite-Ca forms based on the most dominate component. Erionite has a hexagonal, cage-like structure composed of a framework of linked tetrahedra. It consists of white prismatic crystals in radiating groups of crystal fiber. Erionite absorbs up to 20% of its weight in water, has a specific gravity of 2.02 to 2.13, and has gas absorption, ion exchange, and catalytic properties that are highly selective and depend on the molecular size of the absorbed compounds. Zeolites, in general, have good thermal stability, rehydration kinetics, and water vapor adsorptionAdsorption
Adsorption is the adhesion of atoms, ions, biomolecules or molecules of gas, liquid, or dissolved solids to a surface. This process creates a film of the adsorbate on the surface of the adsorbent. It differs from absorption, in which a fluid permeates or is dissolved by a liquid or solid...
capacity.
Carcinogenicity
Erionite is known to be a human carcinogen and is listed by the International Agency for Research on CancerInternational Agency for Research on Cancer
The International Agency for Research on Cancer is an intergovernmental agency forming part of the World Health Organisation of the United Nations....
as a Group 1 Carcinogen. The prevalence of malignant pleural and peritoneal mesothelioma
Peritoneal mesothelioma
Peritoneal mesothelioma is the name given to the cancer that attacks the lining of the abdomen. This type of cancer affects the lining that protects the contents of the abdomen and which also provides a lubricating fluid to enable the organs to move and work properly.The peritoneum is made of two...
due to erionite exposure in the Central Anatolia Region
Central Anatolia Region
The Central Anatolia Region is one of Turkey's seven census-defined geographical regions.- Provinces :Total population: 12,105,975* Aksaray Province* Ankara Province* Çankırı Province* Eskişehir Province* Karaman Province* Kayseri Province...
is very high. Descriptive studies have reported an excess of mortality from mesothelioma in individuals living in three Turkish villages where there was chronic exposure to erionite; only two cases of mesothelioma occurred in the control village, both in women born elsewhere. An excess of lung cancer also was reported in two of the three villages contaminated with erionite. Respirable erionite fibers were detected in air samples collected from the affected villages, and lung tissue samples collected from mesothelioma cases contained erionite fibers. A higher proportion of ferruginous (iron-containing) bodies with a zeolite core were found in inhabitants of the contaminated villages than of those from the two control villages. Erionite is reportedly present in the local volcanic
Volcanic ash
Volcanic ash consists of small tephra, which are bits of pulverized rock and glass created by volcanic eruptions, less than in diameter. There are three mechanisms of volcanic ash formation: gas release under decompression causing magmatic eruptions; thermal contraction from chilling on contact...
tuff
Tuff
Tuff is a type of rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption. Tuff is sometimes called tufa, particularly when used as construction material, although tufa also refers to a quite different rock. Rock that contains greater than 50% tuff is considered...
. There is sufficient evidence of carcinogenicity of erionite in experimental animals. Rats exposed to erionite by inhalation or injection (intrapleural or intraperitoneal) and mice exposed by intraperitoneal injection had high incidences of mesotheliomas.
Exposure
Deposits of fibrous erionite are located in Arizona, Nevada, Oregon, and Utah. These zeolite beds may be up to 15 feet thick and may lie in surface outcroppings. Erionite fibers have been detected in samples of road dust in Nevada and U.S. residents of the Intermountain West may be potentially exposed to fibrous erionite in ambient air. In the summer of 2009 North DakotaNorth Dakota
North Dakota is a state located in the Midwestern region of the United States of America, along the Canadian border. The state is bordered by Canada to the north, Minnesota to the east, South Dakota to the south and Montana to the west. North Dakota is the 19th-largest state by area in the U.S....
began a study of possible erionite exposure among residents. Erionite has also been identified in samples from the Tertiary Arikaree Formation in southeast Montana and northwest South Dakota.
Potential occupational exposure to erionite occurs during the production and mining of other zeolites. In the past, occupational exposure occurred from erionite mining and production operation.
Erionite also was reported to be a minor component in some commercial zeolites. Therefore, the use of other zeolites may result in potential exposure to erionite for the workers and the general population who use the zeolites in a variety of processes and products. Total dust exposures for miners in an open-pit zeolite mine that contained some erionite in Arizona ranged from 0.01 to 13.7 mg/m3; respirable dust in the mining area was 0.01 to 1.4 mg/m3.
Erionite is held responsible for the high incidence of lung cancer
Lung cancer
Lung cancer is a disease characterized by uncontrolled cell growth in tissues of the lung. If left untreated, this growth can spread beyond the lung in a process called metastasis into nearby tissue and, eventually, into other parts of the body. Most cancers that start in lung, known as primary...
, asbestosis
Asbestosis
Asbestosis is a chronic inflammatory and fibrotic medical condition affecting the parenchymal tissue of the lungs caused by the inhalation and retention of asbestos fibers...
, pleural mesothelioma and other lung problems in the Turkish village of Tuzkoy near Nevsehir in the popular tourist region of Cappadoccia