Asbestos mineral identification

Serpentine Family of Minerals
Mg6[Si4O10] (OH)8
Chrysotile orthorhombic
Antigorite monoclinic
Lizardite
monoclinic


Layer Structures
Layer Structure – but with a mismatch problem
Tridymite layer 5.0 × 8.7 Å
Brucite layer

5.4 × 9.3 Å


Chrysotile


Antigorite


Lizardite


Asbestos
Asbestos is a commercial term: Any fibrous mineral utilized in an
industrial process with a 3:1 length to width.
This is a legal and commercial definition, not a mineralogical one.

Uses of Asbestos
Uses:
Fireproofing
Re-enforcing concrete, tiles
Brake linings
Pot holders and ironing board pads
Roofing materials.
Artificial fireplaces and materials
Patching and spackling compounds
Wall and ceiling panels
Pipe and duct insulation
Building insulation


Asbestos Minerals
Amphiboles:
tremolite
anthophyllite

Ca2Mg5Si8O22(OH)2
[] [Mg2Mg5]


Asbestos Minerals
Amphiboles:
tremolite
anthophyllite
riebeckite = ‘crocidolite’
grunerite = ‘amosite’

Ca2Mg5Si8O22(OH)2
[] [Mg2Mg5]
Na2[(Fe,Mg)3Fe3+2]
[] [Fe2Fe2+5]

Asbestos Mines Of South-africa ITE


Asbestos Minerals
Amphiboles:
tremolite
anthophyllite
riebeckite = ‘crocidolite’
grunerite = ‘amosite’

Ca2Mg5Si8O22(OH)2
[] [Mg2Mg5] “
Na2[(Fe,Mg)3Fe3+2] “
[] [Fe2Fe2+5] “

Asbestos Mines Of South-africa ITE

Serpentine:
chrysotile

Mg6Si4O10(OH)8


Health concerns
Exposure from natural and technological sources

Fibers > 5 micrometers long remain in the lower respiratory tract.
Fibers < 3 micrometers can penetrate cell membranes
In time, Mg is lost from chrysotile to form silica structures
Fe is gained around amphiboles, Mg is lost.
Fibers become coated with hemosiderin, ferritin. => O2- radicals


Asbestos Diseases I
1) Asbestosis: Fibrosis of the lung tissue associated with heavy
and prolonged exposure to all types of asbestos. It leads to
breathing problems and heart failure.
Pleural plaques: localized fibrous scars lining the space
surrounding the lungs.


Asbestos Diseases II
2) Mesothelioma: rare, malignant tumors of the pleural, pericardial,
or peritoneal linings.
It has a strong association with crocidolite asbestos. Heavy exposure
to chrysotile does not increase the risk.
It becomes significant 20 years after the 1st exposure and continues to
climb in rate even after 45 years. It is usually fatal [50% of 280 such
deaths per year in US & Canada are linked to asbestos].
The problem is international. Stucco in Greece uses it.


Asbestos Diseases III
3) Bronchoginic carcinoma: lung cancer
Increased death rate appears after 10 to 14 years from 1st
exposure. Incidence peaks after 35 years. Strongly correlated

with smoking. Non-smokers probably are not at risk.
Associated with all types of asbestos.


Asbestos: Scientific Developments and
Implications for Public Policy
Mossman et al. (1990) Science 247, 294-301

Cause

Annual rate
(deaths per million)

Smoking
Home accidents (1-14 yr olds)
Motor vehicle accident, pedestrian
Drowning (5-14 yr olds)
High school football
Aircraft accidents
Whooping cough vaccination
Asbestos exposure in schools

1200
60
32
27
10
6
6
0.05-0.09

Comparative Risks with asbestos


Health Effects of Chrysotile I
Chrysotile:
If one breaths 1 fiber /cc for 8 hours a day, over the
course of 40 years (at 5 liters of air per breath) there
is no health effect over a lifetime.
At 20 fibers per cc, the effects are not statistically
significant.


Health Effects of Chrysotile II
Chrysotile:
At Asbestos, Canada, there were no problems
identified with ingestion of 109 fibers per liter of
drinking water.


Health Effects of Asbestos:
legal considerations
Chrysotile:
At the San Jose Dam, in California, the dump has
serpentinite. It was designated a toxic dump by the EPA.

Tremolite:
Likewise, termolite particles in play sand is considered
hazardous.

Libby, Montana
Zonolite Mountain near Libby, MT, contains deposits of vermiculite,
a widely used mineral material for insulation and soil conditioners.

Expanded
vermiculite

Vermiculite Mine


Tremolite in
Vermiculite
Scanning electron
micrograph of
asbestiform amphibole
from a former
vermiculite mining site
near Libby, Montana.
Source: U.S. Geological
Survey and U.S.
Environmental Protection
Agency, Region 8, Denver,
Colorado.


Libby, Montana
The EPA reported that 23 cases of mesothelioma, a rare type of
asbestos-related cancer, apparently have their origins in Libby. That’s
a rate of one case for every 1,000 residents, 100 times the national

average.


Libby, Montana
18% of those x-rayed in Libby had abnormalities in the
lining of their lungs (pleural abnormalities). The risk of
pleural abnormalities increased with increasing age and
increasing length of residence in the Libby area. The rate
of pleural abnormalities found in groups within the United
States that have no known asbestos exposures ranges
from 0.2% to 2.3%.


Libby, Montana
Asbestos in the vermiculite ore has been blamed for hundreds of
illnesses and at least 200 deaths. The EPA has been cleaning up the
mine site and other contaminated areas in the town since 1999, and
Libby was declared a Superfund site October, 2002.