Asbestos mineral identification

Asbestos MineralsAmphiboles: tremolite Ca2Mg5Si8O22OH2anthophyllite [] [Mg2Mg5]... Asbestos MineralsAmphiboles: tremolite Ca2Mg5Si8O22OH2anthophyllite [] [Mg2Mg5] riebeckite = ‘crocido

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

Uses of Asbestos

Uses:

FireproofingRe-enforcing concrete, tilesBrake linings

Pot holders and ironing board padsRoofing materials

Artificial fireplaces and materialsPatching and spackling compoundsWall and ceiling panels

Pipe and duct insulationBuilding insulation

Asbestos Minerals

Amphiboles:

tremolite Ca2Mg5Si8O22(OH)2anthophyllite [] [Mg2Mg5]

Asbestos Minerals

Amphiboles:

tremolite Ca2Mg5Si8O22(OH)2anthophyllite [] [Mg2Mg5]

riebeckite = ‘crocidolite’ Na2[(Fe,Mg)3Fe3+

Asbestos Minerals

Amphiboles:

tremolite Ca2Mg5Si8O22(OH)2anthophyllite [] [Mg2Mg5] “

riebeckite = ‘crocidolite’ Na2[(Fe,Mg)3Fe3+

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)

Home accidents (1-14 yr olds) 60

Motor vehicle accident, pedestrian 32

Drowning (5-14 yr olds) 27

Whooping cough vaccination 6

Asbestos exposure in schools 0.05-0.09

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 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

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