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DESIGNATIONS
CAS No.: 1332-21-4
Registry name: Asbestos
Chemical name: Asbestos
Synonyms, Trade names: Serpentine asbestos, amphibole asbestos, fibre asbestos, blue asbestos
Chemical name (German): Asbest
Chemical name (French): Amiante
Appearance: fibrous, impure minerals whose colour varies between pure white and green, brown or grey depending on the iron-oxide content; crocidolite is blue (blue asbestos); the fibres are between 20 and 25 nm long; asbestos fibres are smooth and greasy to the touch.
BASIC CHEMICAL AND PHYSICAL DATA
Asbestos is not a chemical element, but rather an umbrella term for two groups of minerals (serpentine and amphibole asbestos)
| Serpentine | Amphibole |
|||||
| Chrysotile | Crocidolite | Amosite | Anthophyllite | Tremolite | Actinolite | |
| Empirical formula: | Mg3 Si205(OH)4 | Na2Fe2(Fe,Mg)3 Si8O22 (OH)2 | (Fe,Mg)7 Si8O22(OH)2 | Mg7 Si8O22(OH)2 | Ca2Mg5 Si8O22(OH)2 | Ca2(Mg,Fe)5 Si8O22(OH)2 |
| Rel. molecul. mass: | 277.13 g | 1,008.82 g | 1,171.83 g | 780.88 g | 812.42 g | 1,091.67 g |
| Density: | 2.2-2.6 g/cm3 | 2.8-3.6 g/cm3 | 2.9-3.3 g/cm3 | 2.8-3.2 g/cm3 | 2.9-3.2 g/cm3 | 3.0-3.21 g/cm3 |
| Melting point: | 1,500°C | 1,200°C | 1,400°C | 1,450°C | 1,315°C | 1,400°C |
Flash point: asbestos is non-combustible, resistant to heat and features a low conductivity in water: insoluble
ORIGIN AND USE
Usage:
Because of its heat-resistance and suppleness and its
capacity for being incorporated into inorganic and organic
binders, asbestos is used in industry for thermal insulation,
fireproofing and sealing in addition to acting as a filler in the
production of countless composites (more than 3000). Economic
exploitation is centred on chrysotile asbestos from the
serpentine group (95 %). 5 % of amphibole asbestos is
used for asbestos-fibre production.
Spun asbestos is used for fireproof, chemical-resistant clothing. When mixed with cement, asbestos is cast to form panels and pipes (70 - 90 % of the world production is used in the construction industry in Western Europe; acc. WHO, 1987). Asbestos has also been used as a filter material in the drinks and pharmaceutical industry and for the manufacture of brake and clutch linings for motor vehicles.
Origin/derivation:
Asbestos is extremely widespread in nature. The most
important deposits are to be found in the former Soviet Union,
Canada and South Africa. Natural emissions are produced for
example by the weathering of serpentine rocks.
Production figures:
Worldwide production in 1983 was in excess of 4 million tons
(WHO, 1987). The main producers are as follows (WHO, 1986):
| USSR | 1983: | 2,250,000 t/a |
| Canada | 1983: | 820,000 t/a |
| South Africa | 1983: | 221,111 t/a |
| Brazil | 1983: | 158,855 t/a |
| Zimbabwe | 1983: | 153,221 t/a |
| Italy | 1983: | 139,054 t/a |
| China | 1983: | 110,000 t/a |
Toxicity
| Humans: | TCLo 2.8 fibres/cm3/5 years | acc. UBA, 1986 |
| TCLo 1.2 fibres/cm3/19 years without interruption | acc. UBA, 1986 | |
| Mammals: | ||
| Rat | TDLo 100 mg/kg, intrapleural | acc. UBA, 1986 |
As yet there are no known characteristic toxicology data (DVGW, 1988).
Characteristic effects:
Humans/mammals: Various asbestos-induced illnesses are known from the industrial-medicine sector in which the size of the fibres plays a crucial role. Generally speaking, fibres with a diameter of less than 2 m m and a length of more than 5 m m are considered to be hazardous to health (diameter : length = 1 : 3). Such a fibre size is capable of entering the lungs, gathering there and becoming encapsulated. Fibres have also been found to have a certain migration capability in the organism and the cell metabolism. Accumulation in the lungs causes sclerosis of the pulmonary alveoli and thus impairs the oxygen exchange.
The inhalation of large quantities of fibre can cause asbestosis which increases the risk of bronchial cancer. In particular, dusts < 200 m m are highly toxic and suspected of being a direct cause of tumours.
Exposure to asbestos irritates the eyes and the respiratory tract. Direct penetration into damaged skin produces excessive hornification. Fibres in the lungs bring about chronic bronchitis, irritation of the pleura and pleurisy. Distension of the lungs can result in lung cancer. Workplace exposure may produce periods of latency in the gastro-intestinal tract lasting up to 40 years.
ENVIRONMENTAL BEHAVIOUR
Water:
Asbestos fibres cause water to become turbid, but are not soluble
in water.
Air:
The dwell time in the atmosphere is dependent on the fibre size.
Asbestos fibres can be transported over hundreds of kilometres in
the atmosphere. Weathering produces short and thin asbestos
fibres from the coarse dust.
Soil:
If asbestos fibres get into the soil, they accumulate on the
surface and may be scattered again at any time. Particles in
excess of 2 m m are not washed
into the soil pores. In the soil itself and in sediments,
asbestos is considered to be harmless (DVGW, 1988). Asbestos
dusts in refuse or on dumps must be covered or moistened during
transportation to stop them ingressing into the air. Soils and
sediments in general are considered as accumulation sites.
Half-life:
The half-life of fibres on mucous membranes is a matter of
minutes - hours or days - years after penetration into the tissue
(HORN, 1989).
Food chain:
Asbestos fibres penetrate into organisms via drinking water. The
pollution of drinking water is caused by fibres in
asbestos-cement pipes. The impact is a function of the
calcium-carbonate saturation of the water and depends on the
number of iron-oxide deposits in the pipes. There is as yet no
proof of oral asbestos intake causing cancer.
ENVIRONMENTAL STANDARDS
| Medium/ acceptor | Sector | Country/ organ. | Status |
Value | Cat. | Remarks | Source |
| Air: | Workp | A | L |
250,000 f/m3 | chrysotile [1991] | acc. Albracht, 1991 | |
| Workp | B | L |
150,000 f/m3 | crocidolite [1987] | acc. Albracht, 1991 | ||
| Workp | B | L |
1,000,000 f/m3 | other asbestos [1987] | acc. Albracht, 1991 | ||
| Workp | CH | L |
1,000,000 f/m3 | dusts [1988] | acc. Albracht, 1991 | ||
| Workp | DK | L |
300,000 f/m3 | crocidolite, ceiling value (15min) [1988] | acc. Albracht, 1991 | ||
| Workp | DK | L |
300,000 f/m3 | other asbestos [1988] | acc. Albracht, 1991 | ||
| Workp | F | L |
500,000 f/m3 | crocidolite [1987] | acc. Albracht, 1991 | ||
| Workp | F | L |
1,000,000 f/m3 | other asbestos [1987] | acc. Albracht, 1991 | ||
| Workp | D | L |
250,000 f/m3 | TRK | chrysotile [1990] | acc. Albracht, 1991 | |
| Workp | D | G |
50,000 f/m3 | TRK | crocidolite, remediation [1990] | acc. Albracht, 1991 | |
| Workp | GB | L |
200,000 f/m3 | crocidolite, 4h [1984] | acc. Albracht, 1991 | ||
| Workp | GB | L |
500,000 f/m3 | other asbestos, 4h, [1984] | acc. Albracht, 1991 | ||
| Workp | DDR | L |
1,000,000 f/m3 | dusts [1983] | acc. Albracht, 1991 | ||
| Workp | DDR | L |
2,000,000 f/m3 | short time value (30 min) [1983] | acc. Albracht, 1991 | ||
| Workp | GR | L |
500,000 f/m3 | crocidolite [1988] | acc. Albracht, 1991 | ||
| Workp | GR | L |
1,000,000 f/m3 | other asbestos [1988] | acc. Albracht, 1991 | ||
| Workp | IRL | L |
500,000 f/m3 | crocidolite [1989] | acc. Albracht, 1991 | ||
| Workp | IRL | L |
1,000,000 f/m3 | other asbestos [1989] | acc. Albracht, 1991 | ||
| Workp | NL | L |
200,000 f/m3 | crocidolite, ceiling value (10 min) [1989] | acc. Albracht, 1991 | ||
| Workp | NL | L |
2,000,000 f/m3 | Other asbestos, 4h [1989] | acc. Albracht, 1991 | ||
| Workp | S | L |
200,000 f/m3 | asbestos (except chrysotile) [1987] | acc. Albracht, 1991 | ||
| Workp | USA | L |
200,000 f/m3 | asbestos [1986] | acc. Albracht, 1991 | ||
| Workp | USA | G |
200,000 f/m3 | amosite | ACGIH, 1988 | ||
| Workp | USA | G |
500,000 f/m3 | crocidolite | ACGIH, 1988 | ||
| Workp | USA | G |
2,000,000 f/m3 | chrysotile, other asbestos | ACGIH, 1988 | ||
| Air | F | (L) |
0.1 mg/m3 | Emission (dust) | acc. MEEK et al, 1985 | ||
| Emiss. | D | L |
0.1 mg/m3 | TA-L | fine dust, mass flow ³ 0.5g/h | acc. TA Luft, 1986 | |
| DDR | L |
0.005 mg/m3 | MIKk | acc. HORN, 1989 | |||
| Foodstuffs: | Drinkw | USA | L |
7,100 fibres/lx103 | Average and long fibres | acc. DVGW, 1988 |
Note: There is virtually a complete ban in Denmark on materials containing asbestos for production, import and utilization. Norway, Sweden and Holland control the asbestos content of insulating materials and consumer goods in supplementary legislation.
Comparison/reference values
| Medium/origin | Country | Value | Source |
| Surface water: | |||
| Northern Lake Constance (1981) | D | < 5 fibres/l x 103 1) | acc. DVGW, 1988 |
| Southern Lake Constance (1981) | D | 10-20 fibres/l x 103 1) | acc. DVGW, 1988 |
| Franconian Forest (1981) | D | 10-50 fibres/l x 103 1) | acc. DVGW, 1988 |
| Bavarian Forest (1981) | D | < 5-30 fibres/l x 103 1) | acc. DVGW, 1988 |
| Groundwater: | |||
| Northern Germany (1981) | D | 4-100 fibres/l x 103 1) | acc. DVGW, 1988 |
| Franconian Forest (1981) | D | < 5-60 fibres/l x 103 1) | acc. DVGW, 1988 |
| Drinking water: | |||
| 10 utility companies (1981) | D | 5-1,000 fibres/l x 103 2) | acc. DVGW, 1988 |
| Montreal (1971) | CDN | 2,000-9,500 fibres/l x 103 | acc. DVGW, 1988 |
| Toronto (1974) | CDN | 700-4,100 fibres/l x 103 | acc. DVGW, 1988 |
| Duluth (1974) | USA | 20,000-75,000 fibres/l x 103 | acc. DVGW, 1988 |
| Chicago (1977) | USA | 80-2,300 fibres/l x 103 | acc. DVGW, 1988 |
Note:
1) Asbestos fibres more than 5 m m long
2) Utility companies with asbestos-cement pipes and a
negative saturation index > 0.2 at tapping point
Assessment/comments
Asbestos fibres are released into the environment by natural and anthropogenic processes. The liberation of asbestos during the manufacture and processing of materials containing asbestos must be significantly reduced especially in confined areas and at workplaces because of the great hazard to the respiratory organs and in particular the lungs. There is increasing speculation that the oral intake of asbestos can cause tumours. Therefore, there is no justification for the further use of asbestos cement in drinking water pipes. Numerous products containing substitute materials are now making it possible to dispense with the use of substances containing asbestos.